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          ovs-vswitchd(8)               Open vSwitch Manual              ovs-vswitchd(8)
          
          
          
          NAME
                 ovs-vswitchd - Open vSwitch daemon
          
          SYNOPSIS
                 ovs-vswitchd [database]
          
          DESCRIPTION
                 A  daemon that manages and controls any number of Open vSwitch switches
                 on the local machine.
          
                 The  database  argument  specifies   how   ovs-vswitchd   connects   to
                 ovsdb-server.   database  may  be an OVSDB active or passive connection
                 method, as described in ovsdb(7).  The default  is  unix:/var/run/open
                 vswitch/db.sock.
          
                 ovs-vswitchd  retrieves its configuration from database at startup.  It
                 sets up Open vSwitch datapaths and then operates switching across  each
                 bridge  described in its configuration files.  As the database changes,
                 ovs-vswitchd automatically updates its configuration to match.
          
                 ovs-vswitchd switches may be configured with any of the following  fea‐
                 tures:
          
                 ?      L2 switching with MAC learning.
          
                 ?      NIC  bonding  with  automatic  fail-over and source MAC-based TX
                        load balancing ("SLB").
          
                 ?      802.1Q VLAN support.
          
                 ?      Port mirroring, with optional VLAN tagging.
          
                 ?      NetFlow v5 flow logging.
          
                 ?      sFlow(R) monitoring.
          
                 ?      Connectivity to an external OpenFlow controller, such as NOX.
          
                 Only a single instance of ovs-vswitchd is intended to run at a time.  A
                 single  ovs-vswitchd  can  manage any number of switch instances, up to
                 the maximum number of supported Open vSwitch datapaths.
          
                 ovs-vswitchd does all the necessary management of  Open  vSwitch  data‐
                 paths  itself.  Thus, ovs-dpctl(8) (and its userspace datapath counter‐
                 parts accessible via ovs-appctl  dpctl/command)  are  not  needed  with
                 ovs-vswitchd and should not be used because they can interfere with its
                 operation.  These tools are still useful for diagnostics.
          
                 An Open vSwitch datapath kernel module must be loaded for  ovs-vswitchd
                 to  be  useful.   Refer to the documentation for instructions on how to
                 build and load the Open vSwitch kernel module.
          
          OPTIONS
                 --mlockall
                        Causes ovs-vswitchd to call the mlockall() function, to  attempt
                        to  lock all of its process memory into physical RAM, preventing
                        the kernel from paging any of its memory to disk.  This helps to
                        avoid networking interruptions due to system memory pressure.
          
                        Some systems do not support mlockall() at all, and other systems
                        only allow privileged users, such as the superuser, to  use  it.
                        ovs-vswitchd emits a log message if mlockall() is unavailable or
                        unsuccessful.
          
             DPDK Options
                 For details on initializing the ovs-vswitchd DPDK  datapath,  refer  to
                 the documentation or ovs-vswitchd.conf.db(5) for details.
          
             Daemon Options
                 The following options are valid on POSIX based platforms.
          
                 --pidfile[=pidfile]
                        Causes a file (by default, ovs-vswitchd.pid) to be created indi‐
                        cating the PID of the running process.  If the pidfile  argument
                        is  not  specified,  or  if it does not begin with /, then it is
                        created in /var/run/openvswitch.
          
                        If --pidfile is not specified, no pidfile is created.
          
                 --overwrite-pidfile
                        By default, when --pidfile is specified and the  specified  pid‐
                        file  already  exists  and  is  locked  by  a  running  process,
                        ovs-vswitchd refuses to start.  Specify  --overwrite-pidfile  to
                        cause it to instead overwrite the pidfile.
          
                        When --pidfile is not specified, this option has no effect.
          
                 --detach
                        Runs  ovs-vswitchd  as a background process.  The process forks,
                        and in the child it starts a new session,  closes  the  standard
                        file descriptors (which has the side effect of disabling logging
                        to the console), and changes its current directory to  the  root
                        (unless --no-chdir is specified).  After the child completes its
                        initialization, the parent exits.   ovs-vswitchd  detaches  only
                        after  it  has  connected to the database, retrieved the initial
                        configuration, and set up that configuration.
          
                 --monitor
                        Creates an additional process to monitor the  ovs-vswitchd  dae‐
                        mon.   If  the daemon dies due to a signal that indicates a pro‐
                        gramming error (SIGABRT, SIGALRM, SIGBUS, SIGFPE,  SIGILL,  SIG
                        PIPE,  SIGSEGV,  SIGXCPU,  or  SIGXFSZ) then the monitor process
                        starts a new copy of it.  If the daemon dies or  exits  for  an‐
                        other reason, the monitor process exits.
          
                        This  option  is  normally used with --detach, but it also func‐
                        tions without it.
          
                 --no-chdir
                        By default, when --detach is specified, ovs-vswitchd changes its
                        current  working  directory  to  the root directory after it de‐
                        taches.  Otherwise, invoking ovs-vswitchd from a carelessly cho‐
                        sen  directory  would  prevent the administrator from unmounting
                        the file system that holds that directory.
          
                        Specifying  --no-chdir  suppresses  this  behavior,   preventing
                        ovs-vswitchd  from changing its current working directory.  This
                        may be useful for collecting core files, since it is common  be‐
                        havior  to  write  core dumps into the current working directory
                        and the root directory is not a good directory to use.
          
                        This option has no effect when --detach is not specified.
          
                 --no-self-confinement
                        By default daemon will try to self-confine itself to  work  with
                        files  under  well-know,  at build-time whitelisted directories.
                        It is better to stick with this default behavior and not to  use
                        this  flag  unless  some other Access Control is used to confine
                        daemon.  Note that in contrast to other access control implemen‐
                        tations  that are typically enforced from kernel-space (e.g. DAC
                        or MAC), self-confinement is imposed from the user-space  daemon
                        itself  and hence should not be considered as a full confinement
                        strategy, but instead should be viewed as an additional layer of
                        security.
          
                 --user Causes  ovs-vswitchd  to  run  as  a different user specified in
                        "user:group", thus dropping most of the root  privileges.  Short
                        forms "user" and ":group" are also allowed, with current user or
                        group are assumed respectively. Only daemons started by the root
                        user accepts this argument.
          
                        On   Linux,   daemons   will   be   granted   CAP_IPC_LOCK   and
                        CAP_NET_BIND_SERVICES before dropping root  privileges.  Daemons
                        that  interact  with  a  datapath, such as ovs-vswitchd, will be
                        granted three  additional  capabilities,  namely  CAP_NET_ADMIN,
                        CAP_NET_BROADCAST  and  CAP_NET_RAW.  The capability change will
                        apply even if the new user is root.
          
                        On Windows, this option is not currently supported. For security
                        reasons,  specifying  this  option will cause the daemon process
                        not to start.
          
             Service Options
                 The following options are valid only on Windows platform.
          
                 --service
                        Causes ovs-vswitchd to run as a service in the  background.  The
                        service  should already have been created through external tools
                        like SC.exe.
          
                 --service-monitor
                        Causes the ovs-vswitchd service to be automatically restarted by
                        the  Windows  services  manager if the service dies or exits for
                        unexpected reasons.
          
                        When --service is not specified, this option has no effect.
          
             Public Key Infrastructure Options
                 -p privkey.pem
                 --private-key=privkey.pem
                        Specifies  a  PEM  file  containing  the  private  key  used  as
                        ovs-vswitchd's identity for outgoing SSL connections.
          
                 -c cert.pem
                 --certificate=cert.pem
                        Specifies a PEM file containing a certificate that certifies the
                        private key specified on -p or --private-key to be  trustworthy.
                        The certificate must be signed by the certificate authority (CA)
                        that the peer in SSL connections will use to verify it.
          
                 -C cacert.pem
                 --ca-cert=cacert.pem
                        Specifies  a  PEM  file  containing  the  CA  certificate   that
                        ovs-vswitchd  should  use to verify certificates presented to it
                        by SSL peers.  (This may be the same certificate that SSL  peers
                        use  to verify the certificate specified on -c or --certificate,
                        or it may be a different one, depending on  the  PKI  design  in
                        use.)
          
                 -C none
                 --ca-cert=none
                        Disables  verification  of  certificates presented by SSL peers.
                        This introduces a security risk, because it means that  certifi‐
                        cates cannot be verified to be those of known trusted hosts.
          
                 --bootstrap-ca-cert=cacert.pem
                        When cacert.pem exists, this option has the same effect as -C or
                        --ca-cert.  If it does not exist, then ovs-vswitchd will attempt
                        to  obtain the CA certificate from the SSL peer on its first SSL
                        connection and save it to the named PEM file.  If it is success‐
                        ful,  it will immediately drop the connection and reconnect, and
                        from then on all SSL connections must be authenticated by a cer‐
                        tificate signed by the CA certificate thus obtained.
          
                        This  option  exposes  the SSL connection to a man-in-the-middle
                        attack obtaining the initial CA certificate, but it may be  use‐
                        ful for bootstrapping.
          
                        This option is only useful if the SSL peer sends its CA certifi‐
                        cate as part of the SSL certificate  chain.   The  SSL  protocol
                        does not require the server to send the CA certificate.
          
                        This option is mutually exclusive with -C and --ca-cert.
          
                 --peer-ca-cert=peer-cacert.pem
                        Specifies  a  PEM file that contains one or more additional cer‐
                        tificates to send to SSL peers.  peer-cacert.pem should  be  the
                        CA certificate used to sign ovs-vswitchd's own certificate, that
                        is, the  certificate  specified  on  -c  or  --certificate.   If
                        ovs-vswitchd's  certificate  is  self-signed, then --certificate
                        and --peer-ca-cert should specify the same file.
          
                        This option is not useful in normal operation, because  the  SSL
                        peer  must  already have the CA certificate for the peer to have
                        any confidence in ovs-vswitchd's identity.  However, this offers
                        a  way for a new installation to bootstrap the CA certificate on
                        its first SSL connection.
          
             Logging Options
                 -v[spec]
                 --verbose=[spec]
                        Sets logging levels.  Without any spec, sets the log  level  for
                        every  module and destination to dbg.  Otherwise, spec is a list
                        of words separated by spaces or commas or colons, up to one from
                        each category below:
          
                        ?      A  valid  module name, as displayed by the vlog/list com‐
                               mand on ovs-appctl(8), limits the log level change to the
                               specified module.
          
                        ?      syslog,  console,  or file, to limit the log level change
                               to only to the system log, to the console, or to a  file,
                               respectively.   (If  --detach  is specified, ovs-vswitchd
                               closes its standard file descriptors, so logging  to  the
                               console will have no effect.)
          
                               On  Windows platform, syslog is accepted as a word and is
                               only useful along with the  --syslog-target  option  (the
                               word has no effect otherwise).
          
                        ?      off,  emer,  err,  warn, info, or dbg, to control the log
                               level.  Messages of the given severity or higher will  be
                               logged,  and  messages of lower severity will be filtered
                               out.  off filters out all  messages.   See  ovs-appctl(8)
                               for a definition of each log level.
          
                        Case is not significant within spec.
          
                        Regardless  of  the  log  levels set for file, logging to a file
                        will not take place unless --log-file is also specified (see be‐
                        low).
          
                        For compatibility with older versions of OVS, any is accepted as
                        a word but has no effect.
          
                 -v
                 --verbose
                        Sets the maximum logging verbosity level, equivalent  to  --ver
                        bose=dbg.
          
                 -vPATTERN:destination:pattern
                 --verbose=PATTERN:destination:pattern
                        Sets  the  log  pattern  for  destination  to pattern.  Refer to
                        ovs-appctl(8) for a description of the valid syntax for pattern.
          
                 -vFACILITY:facility
                 --verbose=FACILITY:facility
                        Sets the RFC5424 facility of the log message.  facility  can  be
                        one  of kern, user, mail, daemon, auth, syslog, lpr, news, uucp,
                        clock, ftp, ntp, audit, alert, clock2, local0,  local1,  local2,
                        local3,  local4, local5, local6 or local7. If this option is not
                        specified, daemon is used as the default for  the  local  system
                        syslog  and local0 is used while sending a message to the target
                        provided via the --syslog-target option.
          
                 --log-file[=file]
                        Enables logging to a file.  If file is  specified,  then  it  is
                        used  as  the exact name for the log file.  The default log file
                        name   used   if   file    is    omitted    is    /var/log/open
                        vswitch/ovs-vswitchd.log.
          
                 --syslog-target=host:port
                        Send  syslog  messages  to  UDP port on host, in addition to the
                        system syslog.  The host must be a numerical IP address,  not  a
                        hostname.
          
                 --syslog-method=method
                        Specify method how syslog messages should be sent to syslog dae‐
                        mon.  Following forms are supported:
          
                        ?      libc, use libc syslog() function.  Downside of using this
                               options  is  that libc adds fixed prefix to every message
                               before it is actually sent  to  the  syslog  daemon  over
                               /dev/log UNIX domain socket.
          
                        ?      unix:file, use UNIX domain socket directly.  It is possi‐
                               ble to specify arbitrary message format with this option.
                               However,  rsyslogd  8.9 and older versions use hard coded
                               parser function anyway that  limits  UNIX  domain  socket
                               use.   If  you  want to use arbitrary message format with
                               older rsyslogd versions, then use UDP socket to localhost
                               IP address instead.
          
                        ?      udp:ip:port, use UDP socket.  With this method it is pos‐
                               sible to use arbitrary message  format  also  with  older
                               rsyslogd.   When  sending syslog messages over UDP socket
                               extra precaution needs to be taken into account, for  ex‐
                               ample,  syslog daemon needs to be configured to listen on
                               the specified UDP port, accidental iptables  rules  could
                               be  interfering  with  local syslog traffic and there are
                               some security considerations that apply to  UDP  sockets,
                               but do not apply to UNIX domain sockets.
          
                        ?      null, discards all messages logged to syslog.
          
                        The  default  is  taken  from  the OVS_SYSLOG_METHOD environment
                        variable; if it is unset, the default is libc.
          
             Other Options
                 --unixctl=socket
                        Sets the name of the control socket on which  ovs-vswitchd  lis‐
                        tens  for  runtime  management  commands (see RUNTIME MANAGEMENT
                        COMMANDS, below).  If socket does not begin with /, it is inter‐
                        preted as relative to /var/run/openvswitch.  If --unixctl is not
                        used   at   all,   the   default   socket   is    /var/run/open
                        vswitch/ovs-vswitchd.pid.ctl,   where   pid   is  ovs-vswitchd's
                        process ID.
          
                        On Windows a local named pipe is used to listen for runtime man‐
                        agement  commands.   A  file  is created in the absolute path as
                        pointed by socket or if --unixctl is not used at all, a file  is
                        created  as ovs-vswitchd.ctl in the configured OVS_RUNDIR direc‐
                        tory.  The file exists just to mimic the behavior of a Unix  do‐
                        main socket.
          
                        Specifying none for socket disables the control socket feature.
          
                 -h
                 --help Prints a brief help message to the console.
          
                 -V
                 --version
                        Prints version information to the console.
          
          RUNTIME MANAGEMENT COMMANDS
                 ovs-appctl(8) can send commands to a running ovs-vswitchd process.  The
                 currently supported commands are described below.  The command descrip‐
                 tions assume an understanding of how to configure Open vSwitch.
          
             GENERAL COMMANDS
                 exit --cleanup
                        Causes  ovs-vswitchd  to  gracefully  terminate. If --cleanup is
                        specified,   release   datapath    resources    configured    by
                        ovs-vswitchd.  Otherwise, datapath flows and other resources re‐
                        mains undeleted.
          
                 qos/show-types interface
                        Queries the interface for a list of  Quality  of  Service  types
                        that are configurable via Open vSwitch for the given interface.
          
                 qos/show interface
                        Queries the kernel for Quality of Service configuration and sta‐
                        tistics associated with the given interface.
          
                 bfd/show [interface]
                        Displays detailed information about Bidirectional Forwarding De‐
                        tection configured on interface.  If interface is not specified,
                        then displays detailed information about all interfaces with BFD
                        enabled.
          
                 bfd/set-forwarding [interface] status
                        Force  the  fault  status of the BFD module on interface (or all
                        interfaces if none is  given)  to  be  status.   status  can  be
                        "true",  "false",  or "normal" which reverts to the standard be‐
                        havior.
          
                 cfm/show [interface]
                        Displays detailed information about Connectivity  Fault  Manage‐
                        ment  configured  on  interface.  If interface is not specified,
                        then displays detailed information about all interfaces with CFM
                        enabled.
          
                 cfm/set-fault [interface] status
                        Force  the  fault  status of the CFM module on interface (or all
                        interfaces if none is  given)  to  be  status.   status  can  be
                        "true",  "false",  or "normal" which reverts to the standard be‐
                        havior.
          
                 stp/tcn [bridge]
                        Forces a topology change event on bridge if  it's  running  STP.
                        This  may  cause it to send Topology Change Notifications to its
                        peers and flush its MAC table.  If no bridge is given, forces  a
                        topology change event on all bridges.
          
                 stp/show [bridge]
                        Displays detailed information about spanning tree on the bridge.
                        If bridge is not specified, then displays  detailed  information
                        about all bridges with STP enabled.
          
                 rstp/tcn [bridge]
                        Forces  a  topology change event on bridge if it's running RSTP.
                        This may cause it to send Topology Change Notifications  to  its
                        peers  and flush its MAC table.  If no bridge is given, forces a
                        topology change event on all bridges.
          
                 rstp/show [bridge]
                        Displays detailed information about rapid spanning tree  on  the
                        bridge.   If bridge is not specified, then displays detailed in‐
                        formation about all bridges with RSTP enabled.
          
             BRIDGE COMMANDS
                 These commands manage bridges.
          
                 fdb/flush [bridge]
                        Flushes bridge MAC address learning table, or all  learning  ta‐
                        bles if no bridge is given.
          
                 fdb/show bridge
                        Lists  each  MAC  address/VLAN  pair  learned  by  the specified
                        bridge, along with the port on which it was learned and the  age
                        of the entry, in seconds.
          
                 fdb/stats-clear [bridge]
                        Clear  bridge MAC address learning table statistics, or all sta‐
                        tistics if no bridge is given.
          
                 fdb/stats-show bridge
                        Show MAC address learning table  statistics  for  the  specified
                        bridge.
          
                 mdb/flush [bridge]
                        Flushes  bridge multicast snooping table, or all snooping tables
                        if no bridge is given.
          
                 mdb/show bridge
                        Lists each multicast group/VLAN pair learned  by  the  specified
                        bridge,  along with the port on which it was learned and the age
                        of the entry, in seconds.
          
                 bridge/reconnect [bridge]
                        Makes bridge drop all of its OpenFlow controller connections and
                        reconnect.   If  bridge  is not specified, then all bridges drop
                        their controller connections and reconnect.
          
                        This command might be useful for debugging  OpenFlow  controller
                        issues.
          
                 bridge/dump-flows bridge
                        Lists  all  flows  in bridge, including those normally hidden to
                        commands such as ovs-ofctl dump-flows.  Flows set up  by  mecha‐
                        nisms  such as in-band control and fail-open are hidden from the
                        controller since it is not allowed to modify or override them.
          
             BOND COMMANDS
                 These commands manage bonded ports on an Open  vSwitch's  bridges.   To
                 understand  some of these commands, it is important to understand a de‐
                 tail of the bonding implementation  called  ``source  load  balancing''
                 (SLB).   Instead  of  directly  assigning  Ethernet source addresses to
                 slaves, the bonding implementation computes a  function  that  maps  an
                 48-bit  Ethernet  source  addresses into an 8-bit value (a ``MAC hash''
                 value).  All of the Ethernet addresses that map to a single 8-bit value
                 are then assigned to a single slave.
          
                 bond/list
                        Lists all of the bonds, and their slaves, on each bridge.
          
                 bond/show [port]
                        Lists  all of the bond-specific information (updelay, downdelay,
                        time until the next rebalance) about the given bonded  port,  or
                        all  bonded  ports  if no port is given.  Also lists information
                        about each slave: whether it is enabled or disabled, the time to
                        completion  of  an  updelay  or downdelay if one is in progress,
                        whether it is the active  slave,  the  hashes  assigned  to  the
                        slave.   Any  LACP information related to this bond may be found
                        using the lacp/show command.
          
                 bond/migrate port hash slave
                        Only valid for SLB bonds.  Assigns a given MAC  hash  to  a  new
                        slave.   port  specifies  the bond port, hash the MAC hash to be
                        migrated (as a decimal number between 0 and 255), and slave  the
                        new slave to be assigned.
          
                        The reassignment is not permanent: rebalancing or fail-over will
                        cause the MAC hash to be shifted to a new  slave  in  the  usual
                        manner.
          
                        A MAC hash cannot be migrated to a disabled slave.
          
                 bond/set-active-slave port slave
                        Sets slave as the active slave on port.  slave must currently be
                        enabled.
          
                        The setting is not permanent: a new active  slave  will  be  se‐
                        lected if slave becomes disabled.
          
                 bond/enable-slave port slave
                 bond/disable-slave port slave
                        Enables (or disables) slave on the given bond port, skipping any
                        updelay (or downdelay).
          
                        This setting is not permanent: it persists only until  the  car‐
                        rier status of slave changes.
          
                 bond/hash mac [vlan] [basis]
                        Returns the hash value which would be used for mac with vlan and
                        basis if specified.
          
                 lacp/show [port]
                        Lists all of the LACP related information about the given  port:
                        active or passive, aggregation key, system id, and system prior‐
                        ity.  Also lists information about each slave: whether it is en‐
                        abled  or  disabled, whether it is attached or detached, port id
                        and priority, actor information, and  partner  information.   If
                        port  is not specified, then displays detailed information about
                        all interfaces with CFM enabled.
          
                 lacp/stats-show [port]
                        Lists various stats about LACP PDUs (number of RX/TX  PDUs,  bad
                        PDUs received) and slave state (number of time slave's state ex‐
                        pired/defaulted and carrier status changed) for the given  port.
                        If  port is not specified, then displays stats of all interfaces
                        with LACP enabled.
          
             DPCTL DATAPATH DEBUGGING COMMANDS
                 The primary way to configure ovs-vswitchd is through the  Open  vSwitch
                 database,  e.g. using ovs-vsctl(8).  These commands provide a debugging
                 interface for managing datapaths.  They  implement  the  same  features
                 (and syntax) as ovs-dpctl(8).  Unlike ovs-dpctl(8), these commands work
                 with datapaths that are integrated into ovs-vswitchd (e.g.  the  netdev
                 datapath type).
          
                 Do   not  use  commands  to  add  or  remove  or  modify  datapaths  if
                 ovs-vswitchd is running because this interferes with ovs-vswitchd's own
                 datapath management.
          
                 dpctl/add-dp dp [netdev[,option]...]
                        Creates datapath dp, with a local port also named dp.  This will
                        fail if a network device dp already exists.
          
                        If netdevs are specified, ovs-vswitchd  adds  them  to  the  new
                        datapath, just as if add-if was specified.
          
                 dpctl/del-dp dp
                        Deletes  datapath  dp.  If dp is associated with any network de‐
                        vices, they are automatically removed.
          
                 dpctl/add-if dp netdev[,option]...
                        Adds each netdev to the set of network devices datapath dp moni‐
                        tors,  where  dp is the name of an existing datapath, and netdev
                        is the name of one of the host's  network  devices,  e.g.  eth0.
                        Once a network device has been added to a datapath, the datapath
                        has complete ownership of the network device's traffic  and  the
                        network device appears silent to the rest of the system.
          
                        A  netdev  may be followed by a comma-separated list of options.
                        The following options are currently supported:
          
                        type=type
                               Specifies the type of port to add.  The default  type  is
                               system.
          
                        port_no=port
                               Requests  a specific port number within the datapath.  If
                               this option is not specified then one will  be  automati‐
                               cally assigned.
          
                        key=value
                               Adds an arbitrary key-value option to the port's configu‐
                               ration.
          
                        ovs-vswitchd.conf.db(5) documents the available port  types  and
                        options.
          
                 dpctl/set-if dp port[,option]...
                        Reconfigures  each  port  in  dp as specified.  An option of the
                        form key=value adds the specified key-value option to  the  port
                        or  overrides  an  existing  key's value.  An option of the form
                        key=, that is, without a value, deletes the key-value named key.
                        The  type  and  port number of a port cannot be changed, so type
                        and port_no are only allowed if they match the existing configu‐
                        ration.
          
                 dpctl/del-if dp netdev...
                        Removes each netdev from the list of network devices datapath dp
                        monitors.
          
                 dpctl/dump-dps
                        Prints the name of each configured datapath on a separate line.
          
                 dpctl/show [-s | --statistics] [dp...]
                        Prints a summary of configured datapaths, including their  data‐
                        path  numbers  and  a  list of ports connected to each datapath.
                        (The local port is identified as port 0.)  If -s or --statistics
                        is specified, then packet and byte counters are also printed for
                        each port.
          
                        The datapath numbers consists of flow stats and mega  flow  mask
                        stats.
          
                        The  "lookups"  row  displays three stats related to flow lookup
                        triggered by processing incoming packets in the datapath.  "hit"
                        displays number of packets matches existing flows. "missed" dis‐
                        plays the number of packets not matching any existing  flow  and
                        require  user space processing.  "lost" displays number of pack‐
                        ets destined for user space process but subsequently dropped be‐
                        fore  reaching  userspace. The sum of "hit" and "miss" equals to
                        the total number of packets datapath processed.
          
                        The "flows" row displays the number of flows in datapath.
          
                        The "masks" row displays the mega flow mask stats. This  row  is
                        omitted  for datapath not implementing mega flow. "hit" displays
                        the total number of masks visited for matching incoming packets.
                        "total" displays number of masks in the datapath. "hit/pkt" dis‐
                        plays the average number of masks visited per packet; the  ratio
                        between "hit" and total number of packets processed by the data‐
                        path.
          
                        If one or more datapaths  are  specified,  information  on  only
                        those datapaths are displayed.  Otherwise, ovs-vswitchd displays
                        information about all configured datapaths.
          
             DATAPATH FLOW TABLE DEBUGGING COMMANDS
                 The following commands are primarily useful for debugging Open vSwitch.
                 The  flow  table entries (both matches and actions) that they work with
                 are not OpenFlow flow entries.  Instead, they are different and consid‐
                 erably  simpler flows maintained by the Open vSwitch kernel module.  Do
                 not use  commands  to  add  or  remove  or  modify  datapath  flows  if
                 ovs-vswitchd  is  running because it interferes with ovs-vswitchd's own
                 datapath flow management.  Use  ovs-ofctl(8),  instead,  to  work  with
                 OpenFlow flow entries.
          
                 The  dp argument to each of these commands is optional when exactly one
                 datapath exists, in which case that datapath is the default.  When mul‐
                 tiple datapaths exist, then a datapath name is required.
          
                 dpctl/dump-flows [-m | --more] [--names | --no-names] [dp] [filter=fil
                 ter] [type=type]
                        Prints to the console all flow entries in datapath dp's flow ta‐
                        ble.   Without  -m  or  --more, output omits match fields that a
                        flow wildcards entirely; with -m or --more, output includes  all
                        wildcarded fields.
          
                        If  filter=filter  is  specified,  only  displays the flows that
                        match the filter. filter is a flow in the form similiar to  that
                        accepted  by  ovs-ofctl(8)'s  add-flow  command. (This is not an
                        OpenFlow flow: besides  other  differences,  it  never  contains
                        wildcards.)   The  filter  is  also  useful  to match wildcarded
                        fields   in   the   datapath   flow.   As   an   example,   fil
                        ter='tcp,tp_src=100'  will  match  the  datapath flow containing
                        'tcp(src=80/0xff00,dst=8080/0xff)'.
          
                        If type=type is specified, only displays flows of the  specified
                        types.  type is a comma separated list, which can contain any of
                        the following:
                           ovs - displays flows handled in the ovs dp
                           tc - displays flows handled in the tc dp
                           offloaded - displays flows offloaded to the HW
                           non-offloaded - displays flows not offloaded to the HW
                           all - displays all the types of flows
          
                        By default all the types of flows are displayed.
          
                 dpctl/add-flow [dp] flow actions
          
                 dpctl/mod-flow [--clear] [--may-create] [-s | --statistics]  [dp]  flow
                 actions
                        Adds  or  modifies a flow in dp's flow table that, when a packet
                        matching flow arrives, causes actions to be executed.
          
                        The add-flow command succeeds only if flow does not already  ex‐
                        ist  in  dp.   Contrariwise,  mod-flow without --may-create only
                        modifies the actions for an existing flow.   With  --may-create,
                        mod-flow will add a new flow or modify an existing one.
          
                        If  -s  or  --statistics  is specified, then mod-flow prints the
                        modified flow's statistics.  A flow's statistics are the  number
                        of  packets  and  bytes  that  have passed through the flow, the
                        elapsed time since the flow last processed a packet  (if  ever),
                        and (for TCP flows) the union of the TCP flags processed through
                        the flow.
          
                        With --clear, mod-flow zeros out  the  flow's  statistics.   The
                        statistics  printed  if -s or --statistics is also specified are
                        those from just before clearing the statistics.
          
                        NOTE: flow and  actions  do  not  match  the  syntax  used  with
                        ovs-ofctl(8)'s add-flow command.
          
                        Usage Examples
          
                        Forward ARP between ports 1 and 2 on datapath myDP:
          
                               ovs-dpctl add-flow myDP \
                                 "in_port(1),eth(),eth_type(0x0806),arp()" 2
          
                               ovs-dpctl add-flow myDP \
                                 "in_port(2),eth(),eth_type(0x0806),arp()" 1
          
                        Forward all IPv4 traffic between two addresses on ports 1 and 2:
          
                               ovs-dpctl add-flow myDP \
                                 "in_port(1),eth(),eth_type(0x800),\
                                  ipv4(src=172.31.110.4,dst=172.31.110.5)" 2
          
                               ovs-dpctl add-flow myDP \
                                 "in_port(2),eth(),eth_type(0x800),\
                                  ipv4(src=172.31.110.5,dst=172.31.110.4)" 1
          
                 dpctl/del-flow [-s | --statistics] [dp] flow
                        Deletes  the flow from dp's flow table that matches flow.  If -s
                        or --statistics is specified, then del-flow prints  the  deleted
                        flow's statistics.
          
                 dpctl/get-flow [dp] ufid:ufid [-m | --more] [--names | --no-names]
                        Fetches  the  flow  from  dp's flow table with unique identifier
                        ufid.  ufid must be specified as  a  string  of  32  hexadecimal
                        characters.
          
                 dpctl/del-flows [dp]
                        Deletes all flow entries from datapath dp's flow table.
          
             CONNECTION TRACKING TABLE COMMANDS
                 The  following  commands  are  useful for debugging and configuring the
                 connection tracking table in the datapath.
          
                 The dp argument to each of these commands is optional when exactly  one
                 datapath exists, in which case that datapath is the default.  When mul‐
                 tiple datapaths exist, then a datapath name is required.
          
                 N.B.(Linux specific): the system datapaths (i.e. the Linux kernel  mod‐
                 ule  Open  vSwitch  datapaths) share a single connection tracking table
                 (which is also used by other kernel subsystems, such as iptables, nfta‐
                 bles and the regular host stack).  Therefore, the following commands do
                 not apply specifically to one datapath.
          
                 dpctl/dump-conntrack [-m | --more] [-s | --statistics] [dp] [zone=zone]
                        Prints to the console all the connection entries in the  tracker
                        used  by  dp.  If zone=zone is specified, only shows the connec‐
                        tions in zone.  With --more, some  implementation  specific  de‐
                        tails  are  included.  With --statistics timeouts and timestamps
                        are added to the output.
          
                 dpctl/flush-conntrack [dp] [zone=zone] [ct-tuple]
                        Flushes the connection entries in the tracker used by  dp  based
                        on  zone and connection tracking tuple ct-tuple.  If ct-tuple is
                        not provided, flushes all the connection entries.  If  zone=zone
                        is specified, only flushes the connections in zone.
          
                        If  ct-tuple is provided, flushes the connection entry specified
                        by ct-tuple in zone. The zone defaults to 0 if it  is  not  pro‐
                        vided.   The userspace connection tracker requires flushing with
                        the original pre-NATed tuple and a warning log will be otherwise
                        generated.  An example of an IPv4 ICMP ct-tuple:
          
                        "ct_nw_src=10.1.1.1,ct_nw_dst=10.1.1.2,ct_nw_proto=1,icmp_type=8,icmp_code=0,icmp_id=10"
          
                        An example of an IPv6 TCP ct-tuple:
          
                        "ct_ipv6_src=fc00::1,ct_ipv6_dst=fc00::2,ct_nw_proto=6,ct_tp_src=1,ct_tp_dst=2"
          
                 dpctl/ct-stats-show [dp] [zone=zone] [-m | --more]
                        Displays  the  number of connections grouped by protocol used by
                        dp.  If zone=zone is specified, numbers refer to the connections
                        in  zone.  With --more, groups by connection state for each pro‐
                        tocol.
          
                 dpctl/ct-bkts [dp] [gt=threshold]
                        For each conntrack bucket, displays the  number  of  connections
                        used  by  dp.   If gt=threshold is specified, bucket numbers are
                        displayed when the number of connections in a bucket is  greater
                        than threshold.
          
                 dpctl/ct-set-maxconns [dp] maxconns
                        Sets the maximum limit of connection tracker entries to maxconns
                        on dp.  This can be used to reduce the processing  load  on  the
                        system  due to connection tracking or simply limiting connection
                        tracking.  If the number of connections is already over the  new
                        maximum  limit  request  then  the new maximum limit will be en‐
                        forced when the number of connections decreases to  that  limit,
                        which normally happens due to connection expiry.  Only supported
                        for userspace datapath.
          
                 dpctl/ct-get-maxconns [dp]
                        Prints the maximum limit of connection tracker  entries  on  dp.
                        Only supported for userspace datapath.
          
                 dpctl/ct-get-nconns [dp]
                        Prints  the  current number of connection tracker entries on dp.
                        Only supported for userspace datapath.
          
                 dpctl/ct-set-limits            [dp]             [default=default_limit]
                 [zone=zone,limit=limit]...
                        Sets  the  maximum allowed number of connections in a connection
                        tracking zone.  A specific zone may be set to limit, and  multi‐
                        ple  zones  may  be specified with a comma-separated list.  If a
                        per-zone limit for a particular zone is  not  specified  in  the
                        datapath,  it defaults to the default per-zone limit.  A default
                        zone may be specified with the  default=default_limit  argument.
                        Initially,  the  default per-zone limit is unlimited.  An unlim‐
                        ited number of entries may be set with 0 limit.  Only  supported
                        for Linux kernel datapath.
          
                 dpctl/ct-del-limits [dp] zone=zone[,zone]...
                        Deletes  the connection tracking limit for zone.  Multiple zones
                        may be specified with a comma-separated  list.   Only  supported
                        for Linux kernel datapath.
          
                 dpctl/ct-get-limits [dp] [zone=zone[,zone]...]
                        Retrieves  the maximum allowed number of connections and current
                        counts per-zone.  If zone is given, only the  specified  zone(s)
                        are printed.  If no zones are specified, all the zone limits and
                        counts are provided.  The command always  displays  the  default
                        zone limit.  Only supported for Linux kernel datapath.
          
             DPIF-NETDEV COMMANDS
                 These  commands are used to expose internal information (mostly statis‐
                 tics) about the "dpif-netdev" userspace datapath. If there is only  one
                 datapath  (as  is often the case, unless dpctl/ commands are used), the
                 dp argument can be omitted. By default the commands  present  data  for
                 all  pmd  threads in the datapath. By specifying the "-pmd Core" option
                 one can filter the output for a single pmd in the datapath.
          
                 dpif-netdev/pmd-stats-show [-pmd core] [dp]
                        Shows performance statistics for one or all pmd threads  of  the
                        datapath dp. The special thread "main" sums up the statistics of
                        every non pmd thread.
          
                        The sum of "emc hits", "smc hits", "megaflow hits" and "miss" is
                        the  number  of packet lookups performed by the datapath. Beware
                        that a recirculated packet experiences one additional lookup per
                        recirculation, so there may be more lookups than forwarded pack‐
                        ets in the datapath.
          
                        Cycles are counted using the TSC  or  similar  facilities  (when
                        available on the platform). The duration of one cycle depends on
                        the processing platform.
          
                        "idle cycles" refers to cycles spent in PMD iterations not  for‐
                        warding  any  any  packets. "processing cycles" refers to cycles
                        spent in PMD iterations forwarding at least one packet,  includ‐
                        ing the cost for polling, processing and transmitting said pack‐
                        ets.
          
                        To reset these counters use dpif-netdev/pmd-stats-clear.
          
                 dpif-netdev/pmd-stats-clear [dp]
                        Resets to zero the per pmd thread performance numbers  shown  by
                        the   dpif-netdev/pmd-stats-show  and  dpif-netdev/pmd-perf-show
                        commands.  It will NOT reset datapath or bridge statistics, only
                        the values shown by the above commands.
          
                 dpif-netdev/pmd-perf-show [-nh] [-it iter_len] [-ms ms_len] [-pmd core]
                 [dp]
                        Shows detailed performance metrics for one or all  pmds  threads
                        of the user space datapath.
          
                        The collection of detailed statistics can be controlled by a new
                        configuration parameter "other_config:pmd-perf-metrics". By  de‐
                        fault it is disabled. The run-time overhead, when enabled, is in
                        the order of 1%.
          
          
                        —      used cycles
                        —      forwared packets
                        —      number of rx batches
                        —      packets/rx batch
                        —      max. vhostuser queue fill level
                        —      number of upcalls
                        —      cycles spent in upcalls
          
                        This raw recorded data is used threefold:
          
          
                        1.     In histograms for each of the following metrics:
                               —      cycles/iteration (logarithmic)
                               —      packets/iteration (logarithmic)
                               —      cycles/packet
                               —      packets/batch
                               —      max. vhostuser qlen (logarithmic)
                               —      upcalls
                               —      cycles/upcall (logarithmic)  The  histograms  bins
                                      are divided linear or logarithmic.
                        2.     A cyclic history of the above metrics for 1024 iterations
                        3.     A  cyclic  history  of the cummulative/average values per
                               millisecond wall clock for the last 1024 milliseconds:
                               —      number of iterations
                               —      avg. cycles/iteration
                               —      packets (Kpps)
                               —      avg. packets/batch
                               —      avg. max vhost qlen
                               —      upcalls
                               —      avg. cycles/upcall
          
                        The command options are:
          
                        -nh    Suppress the histograms
          
                        -it iter_len
                               Display the last iter_len iteration stats
          
                        -ms ms_len
                               Display the last ms_len millisecond stats
          
                        The output always contains the following global PMD statistics:
          
                               Time: 15:24:55.270
                               Measurement duration: 1.008 s
          
                               pmd thread numa_id 0 core_id 1:
          
                                 Iterations:              572817  (1.76 us/it)
                                 - Used TSC cycles:   2419034712  ( 99.9 % of total cycles)
                                 - idle iterations:       486808  ( 15.9 % of used cycles)
                                 - busy iterations:        86009  ( 84.1 % of used cycles)
                                 Rx packets:             2399607  (2381 Kpps, 848 cycles/pkt)
                                 Datapath passes:        3599415  (1.50 passes/pkt)
                                 - EMC hits:              336472  (  9.3 %)
                                 - SMC hits:                   0  ( 0.0 %)
                                 - Megaflow hits:        3262943  ( 90.7 %, 1.00 subtbl lookups/hit)
                                 - Upcalls:                    0  (  0.0 %, 0.0 us/upcall)
                                 - Lost upcalls:               0  (  0.0 %)
                                 Tx packets:             2399607  (2381 Kpps)
                                 Tx batches:              171400  (14.00 pkts/batch)
          
                        Here "Rx packets" actually reflects the number of  packets  for‐
                        warded  by the datapath. "Datapath passes" matches the number of
                        packet lookups as  reported  by  the  dpif-netdev/pmd-stats-show
                        command.
          
                        To  reset the counters and start a new measurement use dpif-net
                        dev/pmd-stats-clear.
          
                 dpif-netdev/pmd-perf-log-set on|off [-b  before]  [-a  after]  [-e|-ne]
                 [-us usec] [-q qlen]
                        The  userspace  "netdev"  datapath  is able to supervise the PMD
                        performance metrics and detect iterations with  suspicious  sta‐
                        tistics according to the following criteria:
          
                        —      The  iteration  lasts  longer than usec microseconds (de‐
                               fault 250).  This can be used to capture events  where  a
                               PMD  is  blocked or interrupted for such a period of time
                               that there is a risk for dropped packets on any of its Rx
                               queues.
          
                        —      The  max  vhost  qlen  exceeds  a threshold qlen (default
                               128). This can be used to infer virtio queue overruns and
                               dropped packets inside a VM, which are not visible in OVS
                               otherwise.
          
                        Such suspicious iterations can be logged together with their it‐
                        eration  statistics in the ovs-vswitchd.log to be able to corre‐
                        late them to packet drop or other events outside OVS.
          
                        The above command enables (on) or disables (off) supervision and
                        logging  at run-time and can be used to adjust the above thresh‐
                        olds for detecting suspicious iterations. By default supervision
                        and logging is disabled.
          
                        The command options are:
          
                        -b before
                               The  number of iterations before the suspicious iteration
                               to be logged (default 5).
          
                        -a after
                               The number of iterations after the  suspicious  iteration
                               to be logged (default 5).
          
                        -e     Extend  logging  interval if another suspicious iteration
                               is detected before logging occurs.
          
                        -ne    Do not extend logging interval if another suspicious  it‐
                               eration is detected before logging occurs (default).
          
                        -q qlen
                               Suspicious  vhost  queue  fill  level threshold. Increase
                               this to 512 if the Qemu supports 1024 virtio queue length
                               (default 128).
          
                        -us usec
                               Change  the duration threshold for a suspicious iteration
                               (default 250 us).
          
                 Note: Logging of suspicious iterations itself consumes  a  considerable
                 amount of processing cycles of a PMD which may be visible in the itera‐
                 tion history.  In the worst case this can lead OVS  to  detect  another
                 suspicious iteration caused by logging.
          
                 If  more  than  100  iterations around a suspicious iteration have been
                 logged once, OVS falls back to the safe default values (-b 5 -a 5  -ne)
                 to  avoid  that  logging  itself continuously causes logging of further
                 suspicious iterations.
          
                 dpif-netdev/pmd-rxq-show [-pmd core] [dp]
                        For one or all pmd threads of the datapath dp show the  list  of
                        queue-ids with port names, which this thread polls.
          
                 dpif-netdev/pmd-rxq-rebalance [dp]
                        Reassigns rxqs to pmds in the datapath dp based on their current
                        usage.
          
             NETDEV-DPDK COMMANDS
                 These commands manage DPDK related ports (type=dpdk*).
          
                 netdev-dpdk/set-admin-state [interface] up | down
                        Change the admin state for DPDK interface to up or down.  If in
                        terface is not specified, then it applies to all DPDK ports.
          
                 netdev-dpdk/detach pci-address
                        Detaches  device with corresponding pci-address from DPDK.  This
                        command can be used to detach device if it wasn't detached auto‐
                        matically  after  port  deletion. Refer to the documentation for
                        details and instructions.
          
                 netdev-dpdk/get-mempool-info [interface]
                        Prints the debug information about memory pool used by DPDK  in
                        terface.   If  called  without arguments, information of all the
                        available mempools will be printed. For additional mempool  sta‐
                        tistics  enable  CONFIG_RTE_LIBRTE_MEMPOOL_DEBUG  while building
                        DPDK.
          
             DATAPATH DEBUGGING COMMANDS
                 These commands query and modify datapaths.  They  are  are  similar  to
                 ovs-dpctl(8) commands.  dpif/show has the additional functionality, be‐
                 yond dpctl/show of printing OpenFlow port numbers.  The other  commands
                 are redundant and will be removed in a future release.
          
                 dpif/dump-dps
                        Prints the name of each configured datapath on a separate line.
          
                 dpif/show
                        Prints  a  summary of configured datapaths, including statistics
                        and a list of connected ports.  The  port  information  includes
                        the  OpenFlow  port  number, datapath port number, and the type.
                        (The local port is identified as OpenFlow port 65534.)
          
                 dpif/dump-flows [-m] dp
                        Prints to the console all flow entries in datapath dp's flow ta‐
                        ble. Without -m, output omits match fields that a flow wildcards
                        entirely; with -m output includes all wildcarded fields.
          
                        This command is primarily useful  for  debugging  Open  vSwitch.
                        The  flow  table  entries that it displays are not OpenFlow flow
                        entries.  Instead, they are different and  considerably  simpler
                        flows maintained by the datapath module.  If you wish to see the
                        OpenFlow flow entries, use ovs-ofctl dump-flows.
          
                 dpif/del-flows dp
                        Deletes all flow entries from datapath dp's flow table  and  un‐
                        derlying datapath implementation (e.g., kernel datapath module).
          
                        This command is primarily useful for debugging Open vSwitch.  As
                        discussed in dpif/dump-flows, these  entries  are  not  OpenFlow
                        flow entries.
          
             OFPROTO COMMANDS
                 These  commands  manage the core OpenFlow switch implementation (called
                 ofproto).
          
                 ofproto/list
                        Lists the names of the running ofproto instances.  These are the
                        names that may be used on ofproto/trace.
          
                 ofproto/trace [options] [dpname] odp_flow [packet]
                 ofproto/trace [options] bridge br_flow [packet]]
                 ofproto/trace-packet-out [options] [dpname] odp_flow [packet] actions
                 ofproto/trace-packet-out [options bridge br_flow  [packet] actions
                        Traces  the  path  of an imaginary packet through switch and re‐
                        ports the path that it  took.   The  initial  treatment  of  the
                        packet varies based on the command:
          
                        ?      ofproto/trace  looks  the  packet up in the OpenFlow flow
                               table, as if the packet had arrived on an OpenFlow port.
          
                        ?      ofproto/trace-packet-out applies the  specified  OpenFlow
                               actions,  as  if  the  packet, flow, and actions had been
                               specified in an OpenFlow ``packet-out'' request.
          
                        The packet's headers (e.g. source and destination) and  metadata
                        (e.g. input port), together called its ``flow,'' are usually all
                        that matter for the purpose of tracing a packet.  You can  spec‐
                        ify the flow in the following ways:
          
                        dpname odp_flow
                               odp_flow  is a flow in the form printed by ovs-dpctl(8)'s
                               dump-flows command.  If all of your bridges have the same
                               type, which is the common case, then you can omit dpname,
                               but if you have bridges of  different  types  (say,  both
                               ovs-netdev  and  ovs-system),  then you need to specify a
                               dpname to disambiguate.
          
                        bridge br_flow
                               br_flow is a flow in the form similar to that accepted by
                               ovs-ofctl(8)'s  add-flow  command.  (This is not an Open‐
                               Flow flow: besides other differences, it  never  contains
                               wildcards.)   bridge  names  of  the bridge through which
                               br_flow should be traced.
          
                        These commands support the following options:
          
                        --generate
                               Generate a packet from the flow (see below for  more  in‐
                               formation).
          
                        --l7 payload
                        --l7-len length
                               Accepted  only with --generate (see below for more infor‐
                               mation).
          
                        --consistent
                               Accepted by ofproto-trace-packet-out only.  With this op‐
                               tion,  the  command rejects actions that are inconsistent
                               with the specified packet.  (An example of  an  inconsis‐
                               tency  is  attempting to strip the VLAN tag from a packet
                               that does not have a VLAN  tag.)   Open  vSwitch  ignores
                               most  forms  of inconsistency in OpenFlow 1.0 and rejects
                               inconsistencies in later versions of OpenFlow.   The  op‐
                               tion is necessary because the command does not ordinarily
                               imply a particular OpenFlow version.   One  exception  is
                               that,  when actions includes an action that only OpenFlow
                               1.1 and later supports (such as push_vlan),  --consistent
                               is automatically enabled.
          
                        --ct-next flags
                               When  the  traced  flow  triggers  conntrack actions, of
                               proto/trace will automatically trace  the  forked  packet
                               processing  pipeline  with user specified ct_state.  This
                               option sets the ct_state flags that the conntrack  module
                               will  report.  The  flags must be a comma- or space-sepa‐
                               rated list of the following connection tracking flags:
          
                               ?      trk: Include to indicate connection  tracking  has
                                      taken place.
          
                               ?      new: Include to indicate a new flow.
          
                               ?      est: Include to indicate an established flow.
          
                               ?      rel: Include to indicate a related flow.
          
                               ?      rpl: Include to indicate a reply flow.
          
                               ?      inv:  Include  to indicate a connection entry in a
                                      bad state.
          
                               ?      dnat: Include to indicate a packet whose  destina‐
                                      tion IP address has been changed.
          
                               ?      snat: Include to indicate a packet whose source IP
                                      address has been changed.
          
                               When --ct-next is unspecified, or when  there  are  fewer
                               --ct-next  options  than ct actions, the flags default to
                               trk,new.
          
                        Most commonly, one specifies only a flow, using one of the forms
                        above,  but sometimes one might need to specify an actual packet
                        instead of just a flow:
          
                        Side effects.
                               Some actions have side effects.  For example, the  normal
                               action  can  update the MAC learning table, and the learn
                               action can change OpenFlow tables.   The  trace  commands
                               only perform side effects when a packet is specified.  If
                               you want side effects to take place, then you must supply
                               a packet.
          
                               (Output  actions  are obviously side effects too, but the
                               trace commands never execute them, even when  one  speci‐
                               fies a packet.)
          
                        Incomplete information.
                               Most  of the time, Open vSwitch can figure out everything
                               about the path of a packet using just the  flow,  but  in
                               some  special  circumstances it needs to look at parts of
                               the packet that are not included in the flow.  When  this
                               is the case, and you do not supply a packet, then a trace
                               command will tell you it needs a packet.
          
                        If you wish to include a packet as part of  a  trace  operation,
                        there are two ways to do it:
          
                        --generate
                               This  option,  added to one of the ways to specify a flow
                               already described, causes Open vSwitch to internally gen‐
                               erate  a  packet  with the flow described and then to use
                               that packet.  If your goal is to  execute  side  effects,
                               then --generate is the easiest way to do it, but --gener
                               ate is not a good way to fill in incomplete  information,
                               because  it  generates packets based on only the flow in‐
                               formation, which means that the  packets  really  do  not
                               have any more information than the flow.
          
                               By  default,  for  protocols that allow arbitrary L7 pay‐
                               loads, the generated packet has 64 bytes of payload.  Use
                               --l7-len to change the payload length, or --l7 to specify
                               the exact contents of the payload.
          
                        packet This form supplies an explicit packet as  a  sequence  of
                               hex digits.  An Ethernet frame is at least 14 bytes long,
                               so there must be at least 28 hex digits.   Obviously,  it
                               is inconvenient to type in the hex digits by hand, so the
                               ovs-pcap(1) and ovs-tcpundump(1) utilities provide easier
                               ways.
          
                               With  this  form,  packet  headers are extracted directly
                               from packet, so the odp_flow or  br_flow  should  specify
                               only metadata. The metadata can be:
          
                               skb_priority
                                      Packet QoS priority.
          
                               pkt_mark
                                      Mark of the packet.
          
                               ct_state
                                      Connection state of the packet.
          
                               ct_zone
                                      Connection tracking zone for packet.
          
                               ct_mark
                                      Connection mark of the packet.
          
                               ct_label
                                      Connection label of the packet.
          
                               tun_id The tunnel ID on which the packet arrived.
          
                               in_port
                                      The port on which the packet arrived.
          
                        The  in_port  value is kernel datapath port number for the first
                        format and OpenFlow port number for the second format. The  num‐
                        bering  of  these two types of port usually differs and there is
                        no relationship.
          
                 Usage examples:
          
                     Trace an unicast ICMP echo request on ingress port 1 to destination
                     MAC 00:00:5E:00:53:01
                         ofproto/trace br in_port=1,icmp,icmp_type=8,\
                         dl_dst=00:00:5E:00:53:01
          
                     Trace  an  unicast ICMP echo reply on ingress port 1 to destination
                     MAC 00:00:5E:00:53:01
                         ofproto/trace br in_port=1,icmp,icmp_type=0,\
                         dl_dst=00:00:5E:00:53:01
          
                     Trace an ARP request on ingress port 1
                         ofproto/trace br in_port=1,arp,arp_op=1
          
                     Trace an ARP reply on ingress port 1
                         ofproto/trace br in_port=1,arp,arp_op=2
          
             VLOG COMMANDS
                 These commands manage ovs-vswitchd's logging settings.
          
                 vlog/set [spec]
                        Sets logging levels.  Without any spec, sets the log  level  for
                        every  module and destination to dbg.  Otherwise, spec is a list
                        of words separated by spaces or commas or colons, up to one from
                        each category below:
          
                        ?      A  valid  module name, as displayed by the vlog/list com‐
                               mand on ovs-appctl(8), limits the log level change to the
                               specified module.
          
                        ?      syslog,  console,  or file, to limit the log level change
                               to only to the system log, to the console, or to a  file,
                               respectively.
          
                               On  Windows platform, syslog is accepted as a word and is
                               only useful along with the  --syslog-target  option  (the
                               word has no effect otherwise).
          
                        ?      off,  emer,  err,  warn, info, or dbg, to control the log
                               level.  Messages of the given severity or higher will  be
                               logged,  and  messages of lower severity will be filtered
                               out.  off filters out all  messages.   See  ovs-appctl(8)
                               for a definition of each log level.
          
                        Case is not significant within spec.
          
                        Regardless  of  the  log  levels set for file, logging to a file
                        will not take place unless ovs-vswitchd  was  invoked  with  the
                        --log-file option.
          
                        For compatibility with older versions of OVS, any is accepted as
                        a word but has no effect.
          
                 vlog/set PATTERN:destination:pattern
                        Sets the log pattern  for  destination  to  pattern.   Refer  to
                        ovs-appctl(8) for a description of the valid syntax for pattern.
          
                 vlog/list
                        Lists the supported logging modules and their current levels.
          
                 vlog/list-pattern
                        Lists logging patterns used for each destination.
          
                 vlog/close
                        Causes  ovs-vswitchd to close its log file, if it is open.  (Use
                        vlog/reopen to reopen it later.)
          
                 vlog/reopen
                        Causes ovs-vswitchd to close its log file, if it  is  open,  and
                        then  reopen  it.   (This is useful after rotating log files, to
                        cause a new log file to be used.)
          
                        This has no effect unless  ovs-vswitchd  was  invoked  with  the
                        --log-file option.
          
                 vlog/disable-rate-limit [module]...
                 vlog/enable-rate-limit [module]...
                        By  default,  ovs-vswitchd limits the rate at which certain mes‐
                        sages can be logged.  When a  message  would  appear  more  fre‐
                        quently  than  the  limit,  it  is  suppressed.  This saves disk
                        space, makes logs easier to read, and speeds up  execution,  but
                        occasionally  troubleshooting  requires more detail.  Therefore,
                        vlog/disable-rate-limit allows rate limits to be disabled at the
                        level  of  an individual log module.  Specify one or more module
                        names, as displayed by the vlog/list command.  Specifying either
                        no  module  names at all or the keyword any disables rate limits
                        for every log module.
          
                        The vlog/enable-rate-limit command, whose syntax is the same  as
                        vlog/disable-rate-limit,  can  be used to re-enable a rate limit
                        that was previously disabled.
          
             MEMORY COMMANDS
                 These commands report memory usage.
          
                 memory/show
                        Displays some basic statistics about ovs-vswitchd's  memory  us‐
                        age.  ovs-vswitchd also logs this information soon after startup
                        and periodically as its memory consumption grows.
          
             COVERAGE COMMANDS
                 These commands manage ovs-vswitchd's ``coverage counters,'' which count
                 the  number of times particular events occur during a daemon's runtime.
                 In addition to these commands, ovs-vswitchd automatically logs coverage
                 counter  values,  at INFO level, when it detects that the daemon's main
                 loop takes unusually long to run.
          
                 Coverage counters are useful mainly for performance analysis and debug‐
                 ging.
          
                 coverage/show
                        Displays the averaged per-second rates for the last few seconds,
                        the last minute and the last hour, and the total counts  of  all
                        of the coverage counters.
          
             OPENVSWITCH TUNNELING COMMANDS
                 These commands query and modify OVS tunnel components.
          
                 ovs/route/add ipv4_address/plen output_bridge [GW]
                        Adds  ipv4_address/plen  route  to  vswitchd routing table. out‐
                        put_bridge needs to be OVS bridge name.  This command is  useful
                        if OVS cached routes does not look right.
          
                 ovs/route/show
                        Print  all  routes  in  OVS  routing table, This includes routes
                        cached from system routing table and user configured routes.
          
                 ovs/route/del ipv4_address/plen
                        Delete ipv4_address/plen route from OVS routing table.
          
                 tnl/neigh/show
          
                 tnl/arp/show
                        OVS builds ARP cache by  snooping  are  messages.  This  command
                        shows ARP cache table.
          
                 tnl/neigh/set bridge ip mac
          
                 tnl/arp/set bridge ip mac
                        Adds  or  modifies  an  ARP cache entry in bridge, mapping ip to
                        mac.
          
                 tnl/neigh/flush
          
                 tnl/arp/flush
                        Flush ARP table.
          
                 tnl/egress_port_range [num1] [num2]
                        Set range for UDP source port used for UDP  based  Tunnels.  For
                        example  VxLAN.  If  case  of zero arguments this command prints
                        current range in use.
          
          OPENFLOW IMPLEMENTATION
                 This section documents aspects of OpenFlow for which the OpenFlow spec‐
                 ification requires documentation.
          
             Packet buffering.
                 The OpenFlow specification, version 1.2, says:
          
                        Switches  that  implement  buffering  are  expected  to  expose,
                        through documentation, both the amount of  available  buffering,
                        and the length of time before buffers may be reused.
          
                 Open vSwitch does not maintains any packet buffers.
          
             Bundle lifetime
                 The OpenFlow specification, version 1.4, says:
          
                        If  the  switch  does  not  receive  any  OFPT_BUNDLE_CONTROL or
                        OFPT_BUNDLE_ADD_MESSAGE message for an opened  bundle_id  for  a
                        switch  defined  time  greater  than  1s, it may send an ofp_er‐
                        ror_msg with OFPET_BUNDLE_FAILED type and  OFPBFC_TIMEOUT  code.
                        If the switch does not receive any new message in a bundle apart
                        from echo request and replies for a switch defined time  greater
                        than  1s,  it may send an ofp_error_msg with OFPET_BUNDLE_FAILED
                        type and OFPBFC_TIMEOUT code.
          
                 Open vSwitch implements default idle bundle  lifetime  of  10  seconds.
                 (This  is  configurable  via  other-config:bundle-idle-timeout  in  the
                 Open_vSwitch table. See ovs-vswitchd.conf.db(5) for details.)
          
          LIMITS
                 We believe these limits to be accurate as of this writing.  These  lim‐
                 its assume the use of the Linux kernel datapath.
          
                 ?      ovs-vswitchd  started  through  ovs-ctl(8)  provides  a limit of
                        65535 file descriptors.  The limits on the number of bridges and
                        ports  is decided by the availability of file descriptors.  With
                        the Linux kernel datapath, creation of a single bridge  consumes
                        three  file  descriptors  and adding a port consumes "n-handler-
                        threads" file descriptors per bridge port.  Performance will de‐
                        grade beyond 1,024 ports per bridge due to fixed hash table siz‐
                        ing.  Other platforms may have different limitations.
          
                 ?      2,048 MAC learning entries per bridge,  by  default.   (This  is
                        configurable  via  other-config:mac-table-size in the Bridge ta‐
                        ble.  See ovs-vswitchd.conf.db(5) for details.)
          
                 ?      Kernel flows are limited only by memory available to the kernel.
                        Performance  will  degrade  beyond  1,048,576  kernel  flows per
                        bridge with a 32-bit kernel, beyond 262,144 with a  64-bit  ker‐
                        nel.  (ovs-vswitchd should never install anywhere near that many
                        flows.)
          
                 ?      OpenFlow flows are limited only by  available  memory.   Perfor‐
                        mance is linear in the number of unique wildcard patterns.  That
                        is, an OpenFlow table that contains many flows that all match on
                        the  same fields in the same way has a constant-time lookup, but
                        a table that contains many flows that match on different  fields
                        requires lookup time linear in the number of flows.
          
                 ?      255  ports per bridge participating in 802.1D Spanning Tree Pro‐
                        tocol.
          
                 ?      32 mirrors per bridge.
          
                 ?      15 bytes for the name of a port.  (This is a Linux kernel  limi‐
                        tation.)
          
          SEE ALSO
                 ovs-appctl(8), ovsdb-server(1).
          
          
          
          Open vSwitch                        2.10.90                    ovs-vswitchd(8)
          
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