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.   The  default is unix:/var/run/openvswitch/db.sock.  The
       following forms are accepted:

       ssl:ip:port
              The specified SSL port on the host at the given ip,  which  must
              be  expressed  as an IP address (not a DNS name) in IPv4 or IPv6
              address format.  If ip is an IPv6 address,  then  wrap  ip  with
              square   brackets,  e.g.:  ssl:[::1]:6640.   The  --private-key,
              --certificate, and --ca-cert options  are  mandatory  when  this
              form is used.

       tcp:ip:port
              Connect  to  the  given  TCP port on ip, where ip can be IPv4 or
              IPv6 address. If ip is an IPv6 address, then wrap ip with square
              brackets, e.g.: tcp:[::1]:6640.

       unix:file
              On POSIX, connect to the Unix domain server socket named file.

              On Windows, connect to a local named pipe that is represented by
              a file created in the path file to mimic the behavior of a  Unix
              domain socket.

       pssl:port[:ip]
              Listen on the given SSL port for a connection.  By default, con‐
              nections are not bound to a particular local IP address  and  it
              listens only on IPv4 (but not IPv6) addresses, but specifying ip
              limits connections to those from the given ip,  either  IPv4  or
              IPv6  address.   If  ip  is  an  IPv6 address, then wrap ip with
              square  brackets,  e.g.:  pssl:6640:[::1].   The  --private-key,
              --certificate,  and  --ca-cert  options  are mandatory when this
              form is used.

       ptcp:port[:ip]
              Listen on the given TCP port for a connection.  By default, con‐
              nections  are  not bound to a particular local IP address and it
              listens only on IPv4 (but not IPv6) addresses,  but  ip  may  be
              specified to listen only for connections to the given ip, either
              IPv4 or IPv6 address.  If ip is an IPv6 address,  then  wrap  ip
              with square brackets, e.g.: ptcp:6640:[::1].

       punix:file
              On POSIX, listen on the Unix domain server socket named file for
              a connection.

              On Windows, listen on a local named pipe.  A file is created  in
              the path file to mimic the behavior of a Unix domain socket.

       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, external tools, such ovs-dpctl(8), are not needed
       for managing datapaths in conjunction with ovs-vswitchd, and their  use
       to modify datapaths when ovs-vswitchd is running can interfere with its
       operation.  (ovs-dpctl may still be 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
              another 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
              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 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 two additional capabilities,  namely  CAP_NET_ADMIN  and
              CAP_NET_RAW.  The  capability change will apply even if 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.

   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
              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 --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.  This is the default
                     behavior.  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
                     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  sock‐
                     ets, but do not apply to UNIX domain sockets.

   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
              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
       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   Causes ovs-vswitchd to gracefully terminate.

       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
              Detection  configured  on interface.  If interface is not speci‐
              fied, 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  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
              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.

   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.

       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
       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 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
              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.

   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).

       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 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
              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" 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.  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] [dp] [filter=filter]
              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)'.

       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.

       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
              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 DEBUGGING COMMANDS
       The  following  commands are primarily useful for debugging the connec‐
       tion tracking entries 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
              details  are included. With --statistics timeouts and timestamps
              are added to the output.

       dpctl/flush-conntrack [dp] [zone=zone]
              Flushes all the connection entries in the tracker  used  by  dp.
              If zone=zone is specified, only flushes the connections in zone.

   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.

       dpif-netdev/pmd-stats-show [dp]
              Shows performance statistics for each pmd thread of the datapath
              dp.  The special thread ``main'' sums up the statistics of every
              non pmd thread.  The sum of ``emc hits'',  ``masked  hits''  and
              ``miss''  is  the  number  of  packets received by the datapath.
              Cycles are counted using the TSC  or  similar  facilities  (when
              available  on  the platform).  To reset these counters use dpif-
              netdev/pmd-stats-clear. The duration of one cycle depends on the
              measuring infrastructure.

       dpif-netdev/pmd-stats-clear [dp]
              Resets  to  zero the per pmd thread performance numbers shown by
              the dpif-netdev/pmd-stats-show command.  It will NOT reset data‐
              path  or  bridge  statistics, only the values shown by the above
              command.

       dpif-netdev/pmd-rxq-show [dp]
              For each pmd thread of the datapath dp shows list  of  queue-ids
              with port names, which this thread polls.

   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 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
              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  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 [dpname] odp_flow [-generate | packet]
       ofproto/trace bridge br_flow [-generate | packet]
       ofproto/trace-packet-out  [-consistent]  [dpname] odp_flow [-generate |
       packet] actions
       ofproto/trace-packet-out  [-consistent]  bridge  br_flow  [-generate  |
       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  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.

              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 -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.

              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.

              ofproto-trace-packet-out   accepts   an  additional  -consistent
              option.  With this option specified, the command rejects actions
              that are inconsistent 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  incon‐
              sistencies  in later versions of OpenFlow.  The option is neces‐
              sary 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.

       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
              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 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_error_msg  with  OFPET_BUNDLE_FAILED type and OFPBFC_TIMEOUT
              code.  If the switch does not receive any new message in a  bun‐
              dle  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 idle bundle lifetime of 10 seconds.

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
              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  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                        2.7.90                     ovs-vswitchd(8)