NAME | SYNOPSIS | DESCRIPTION | OPTIONS | RUNTIME MANAGEMENT COMMANDS | OPENFLOW IMPLEMENTATION | LIMITS | SEE ALSO | COLOPHON

ovs-vswitchd(8)              Open vSwitch Manual             ovs-vswitchd(8)

NAME         top

       ovs-vswitchd - Open vSwitch daemon

SYNOPSIS         top

       ovs-vswitchd [database]

DESCRIPTION         top

       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:/usr/local/var/run/openvswitch/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
       features:

       ·      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
       datapaths itself.  Thus, ovs-dpctl(8) (and its userspace datapath
       counterparts 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         top

       --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
              indicating 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 /usr/local/var/run/openvswitch.

              If --pidfile is not specified, no pidfile is created.

       --overwrite-pidfile
              By default, when --pidfile is specified and the specified
              pidfile 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
              daemon.  If the daemon dies due to a signal that indicates a
              programming error (SIGABRT, SIGALRM, SIGBUS, SIGFPE, SIGILL,
              SIGPIPE, SIGSEGV, SIGXCPU, or SIGXFSZ) then the monitor
              process starts a new copy of it.  If the daemon dies or exits
              for another reason, the monitor process exits.

              This option is normally used with --detach, but it also
              functions without it.

       --no-chdir
              By default, when --detach is specified, ovs-vswitchd changes
              its current working directory to the root directory after it
              detaches.  Otherwise, invoking ovs-vswitchd from a carelessly
              chosen 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 behavior 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
              implementations 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
              certificates 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 successful, it will immediately drop the connection and
              reconnect, and from then on all SSL connections must be
              authenticated by a certificate 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
              useful for bootstrapping.

              This option is only useful if the SSL peer sends its CA
              certificate 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
              certificates 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
                     command 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
              below).

              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
              --verbose=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
              /usr/local/var/log/openvswitch/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
              daemon.  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
                     possible 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
                     possible 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 example, 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
              listens for runtime management commands (see RUNTIME
              MANAGEMENT COMMANDS, below).  If socket does not begin with /,
              it is interpreted as relative to
              /usr/local/var/run/openvswitch.  If --unixctl is not used at
              all, the default socket is
              /usr/local/var/run/openvswitch/ovs-vswitchd.pid.ctl, where pid
              is ovs-vswitchd's process ID.

              On Windows a local named pipe is used to listen for runtime
              management 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 directory.  The file exists just to mimic the
              behavior of a Unix domain 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         top

       ovs-appctl(8) can send commands to a running ovs-vswitchd process.
       The currently supported commands are described below.  The command
       descriptions 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
              remains 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
              statistics associated with the given interface.

       bfd/show [interface]
              Displays detailed information about Bidirectional Forwarding
              Detection 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
              behavior.

       cfm/show [interface]
              Displays detailed information about Connectivity Fault
              Management 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
              behavior.

       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
              information about all bridges with RSTP enabled.

   BRIDGE COMMANDS
       These commands manage bridges.

       fdb/flush [bridge]
              Flushes bridge MAC address learning table, or all learning
              tables 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
              statistics 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
              mechanisms 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
       detail 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
              selected 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
              carrier 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 priority.  Also lists information about each slave:
              whether it is enabled 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
              expired/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
              devices, they are automatically removed.

       dpctl/add-if dp netdev[,option]...
              Adds each netdev to the set of network devices datapath dp
              monitors, 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
                     automatically assigned.

              key=value
                     Adds an arbitrary key-value option to the port's
                     configuration.

              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
              configuration.

       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
              datapath 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" displays the number of packets not matching any
              existing flow and require user space processing.  "lost"
              displays number of packets destined for user space process but
              subsequently dropped before 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" displays the average number of masks
              visited per packet; the ratio between "hit" and total number
              of packets processed by the datapath.

              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 considerably 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 multiple datapaths exist, then a datapath name is required.

       dpctl/dump-flows [-m | --more] [--names | --no-names] [dp]
       [filter=filter] [type=type]
              Prints to the console all flow entries in datapath dp's flow
              table.  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,
              filter='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
              exist 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 multiple datapaths exist, then a datapath name is required.

       N.B.(Linux specific): the system datapaths (i.e. the Linux kernel
       module Open vSwitch datapaths) share a single connection tracking
       table (which is also used by other kernel subsystems, such as
       iptables, nftables and the regular host stack).  Therefore, the
       following commands do not apply specifically to one datapath.

       dpctl/ipf-set-enabled [dp] v4|v6
       dpctl/ipf-set-disabled [dp] v4|v6
              Enables or disables IP fragmentation handling for the
              userspace connection tracker.  Either v4 or v6 must be
              specified.  Both IPv4 and IPv6 fragment reassembly are enabled
              by default.  Only supported for the userspace datapath.

       dpctl/ipf-set-min-frag [dp] v4|v6 minfrag
              Sets the minimum fragment size (L3 header and data) for non-
              final fragments to minfrag.  Either v4 or v6 must be
              specified.  For enhanced DOS security, higher minimum fragment
              sizes can usually be used.  The default IPv4 value is 1200 and
              the clamped minimum is 400.  The default IPv6 value is 1280,
              with a clamped minimum of 400, for testing flexibility.  The
              maximum fragment size is not clamped, however, setting this
              value too high might result in valid fragments being dropped.
              Only supported for userspace datapath.

       dpctl/ipf-set-max-nfrags [dp] maxfrags
              Sets the maximum number of fragments tracked by the userspace
              datapath connection tracker to maxfrags.  The default value is
              1000 and the clamped maximum is 5000.  Note that packet
              buffers can be held by the fragmentation module while
              fragments are incomplete, but will timeout after 15 seconds.
              Memory pool sizing should be set accordingly when
              fragmentation is enabled.  Only supported for userspace
              datapath.

       dpctl/ipf-get-status [dp] [-m | --more]
              Gets the configuration settings and fragment counters
              associated with the fragmentation handling of the userspace
              datapath connection tracker.  With -m or --more, also dumps
              the IP fragment lists.  Only supported for userspace 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
              connections in zone.  With --more, some implementation
              specific details 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 provided.  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 protocol.

       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 enforced 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
              multiple 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 unlimited 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
       statistics) 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 packets 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
              forwarding any any packets. "processing cycles" refers to
              cycles spent in PMD iterations forwarding at least one packet,
              including the cost for polling, processing and transmitting
              said packets.

              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 default 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-
              netdev/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
                     (default 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
              iteration statistics in the ovs-vswitchd.log to be able to
              correlate 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
              thresholds for detecting suspicious iterations. By default
              supervision and logging is disabled.

              The command options are:

              -b before
                     The number of iterations before the suspicious itera‐
                     tion 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
                     iteration 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 itera‐
                     tion (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
       iteration 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 fur‐
       ther 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 cur‐
              rent 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
              interface 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 automatically after port deletion. Refer to the docu‐
              mentation for details and instructions.

       netdev-dpdk/get-mempool-info [interface]
              Prints the debug information about memory pool used by DPDK
              interface.  If called without arguments, information of all
              the available mempools will be printed. For additional mempool
              statistics enable CONFIG_RTE_LIBRTE_MEMPOOL_DEBUG while build‐
              ing 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,
       beyond dpctl/show of printing OpenFlow port numbers.  The other com‐
       mands 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
              table. Without -m, output omits match fields that a flow wild‐
              cards 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
              underlying datapath implementation (e.g., kernel datapath mod‐
              ule).

              This command is primarily useful for debugging Open vSwitch.
              As discussed in dpif/dump-flows, these entries are not Open‐
              Flow 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
              reports 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 meta‐
              data (e.g. input port), together called its ``flow,'' are usu‐
              ally all that matter for the purpose of tracing a packet.  You
              can specify 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
                     OpenFlow flow: besides other differences, it never con‐
                     tains 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
                     information).

              --l7 payload
              --l7-len length
                     Accepted only with --generate (see below for more
                     information).

              --consistent
                     Accepted by ofproto-trace-packet-out only.  With this
                     option, the command rejects actions that are inconsis‐
                     tent with the specified packet.  (An example of an
                     inconsistency 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 option 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,
                     ofproto/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-separated list of the following connec‐
                     tion 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 desti‐
                            nation 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 nor‐
                     mal 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 every‐
                     thing 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
                     generate 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 --generate is not a good way to fill in incomplete
                     information, because it generates packets based on only
                     the flow information, 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.  Obvi‐
                     ously, 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
              numbering 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 destina‐
           tion 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 fil‐
                     tered 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 pat‐
              tern.

       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.  Specify‐
              ing 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
              usage.  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
       debugging.

       coverage/show
              Displays the averaged per-second rates for the last few sec‐
              onds, 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 use‐
              ful 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         top

       This section documents aspects of OpenFlow for which the OpenFlow
       specification 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_error_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         top

       We believe these limits to be accurate as of this writing.  These
       limits 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 degrade beyond 1,024 ports per bridge due to
              fixed hash table sizing.  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
              table.  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 kernel.  (ovs-vswitchd should never install anywhere
              near that many flows.)

       ·      OpenFlow flows are limited only by available memory.
              Performance 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
              Protocol.

       ·      32 mirrors per bridge.

       ·      15 bytes for the name of a port.  (This is a Linux kernel
              limitation.)

SEE ALSO         top

       ovs-appctl(8), ovsdb-server(1).

COLOPHON         top

       This page is part of the Open vSwitch (a distributed virtual
       multilayer switch) project.  Information about the project can be
       found at ⟨http://openvswitch.org/⟩.  If you have a bug report for
       this manual page, send it to bugs@openvswitch.org.  This page was
       obtained from the project's upstream Git repository
       ⟨https://github.com/openvswitch/ovs.git⟩ on 2019-05-09.  (At that
       time, the date of the most recent commit that was found in the repos‐
       itory was 2019-05-08.)  If you discover any rendering problems in
       this HTML version of the page, or you believe there is a better or
       more up-to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not part
       of the original manual page), send a mail to man-pages@man7.org

Open vSwitch                       2.11.90                   ovs-vswitchd(8)

Pages that refer to this page: ovs-pcap(1)ovs-tcpundump(1)ovn-architecture(7)ovn-controller(8)ovs-appctl(8)ovs-ctl(8)ovs-dpctl(8)ovs-l3ping(8)ovs-ofctl(8)ovs-tcpdump(8)ovs-vsctl(8)