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 follow-
ing 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). 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.
unix:file
Connect to the Unix domain server socket named file.
pssl:port[:ip]
Listen on the given SSL port for a connection. By default, ovs-vswitchd listens for connections to any local IP address, but speci-
fying ip limits connections to those from the given ip. 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, ovs-vswitchd listens for connections to any local IP address, but ip may
be specified to listen only for connections to the given ip.
punix:file
Listen on the Unix domain server socket named file for a connection.
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.
Upon receipt of a SIGHUP signal, ovs-vswitchd reopens its log file, if one was specified on the command line.
ovs-vswitchd switches may be configured with any of the following features:
o L2 switching with MAC learning.
o NIC bonding with automatic fail-over and source MAC-based TX load balancing ("SLB").
o 802.1Q VLAN support.
o Port mirroring, with optional VLAN tagging.
o NetFlow v5 flow logging.
o sFlow(R) monitoring.
o 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, 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. Please refer to the INSTALL.Linux file included in
the Open vSwitch distribution 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.
--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 /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
Causes ovs-vswitchd to detach itself from the foreground session and run as a background process. 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 (e.g. SIGSEGV, SIGABRT), then the monitor process starts a new copy of it. If the daemon die 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.
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 dif-
ferent 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, but ovs-controller(8) can be configured to do so with the --peer-ca-cert option.
This option is mutually exclusive with -C and --ca-cert.
-vmodule[:facility[:level]], --verbose=module[:facility[:level]]
Sets the logging level for module in facility to level:
o module may be any valid module name (as displayed by the --list action on ovs-appctl(8)), or the special name ANY to set the
logging levels for all modules.
o facility may be syslog, console, or file to set the levels for logging to the system log, the console, or a file respec-
tively, or ANY to set the logging levels for both facilities. If it is omitted, facility defaults to ANY.
Regardless of the log levels set for file, logging to a file will not take place unless --log-file is also specified (see
below).
o level must be one of off, emer, err, warn, info, or dbg, designating the minimum severity of a message for it to be logged.
If it is omitted, level defaults to dbg. See ovs-appctl(8) for a definition of each log level.
-v, --verbose
Sets the maximum logging verbosity level, equivalent to --verbose=ANY:ANY:dbg.
-vPATTERN:facility:pattern, --verbose=PATTERN:facility:pattern
Sets the log pattern for facility to pattern. Refer to ovs-appctl(8) for a description of the valid syntax for pattern.
--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/openvswitch/ovs-vswitchd.log.
-h, --help
Prints a brief help message to the console.
-V, --version
Prints version information to the console.
--check-leaks=file
Logs information about memory allocation and deallocation to file, to allow for debugging memory leaks in ovs-vswitchd. This option
slows down ovs-vswitchd considerably, so it should only be used when a memory leak is suspected. Use the ovs-parse-leaks script to
interpret the leak file.
--leak-limit=size
Limits size of the leak file as specified by --check-leaks to size bytes. Finding leaks sometimes requires allowing the leak file
to grow very large, up to 1GB. By default, files are limited to 10MB.
RUNTIME MANAGEMENT COMMANDS
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 Causes ovs-vswitchd to gracefully terminate.
coverage/log
Logs coverage counters at level warn.
qos/show interface
Queries the kernel for Quality of Service configuration and statistics associated with the given interface.
cfm/show [interface]
Displays detailed information about Connectivity Fault Management configured on interface. If interface is not specified, then dis-
plays detailed information about all interfaces with CFM 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.
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 about the given bonded port: updelay, downdelay, time until the next rebalance. 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 MAC hashes assigned to the slave, and the MAC learning table entries that hash to
each MAC. 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 man-
ner.
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 prior-
ity, actor information, and partner information. If port is not specified, then displays detailed information about all interfaces
with CFM enabled.
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 switch priority tun_id in_port packet
ofproto/trace switch odp_flow -generate
Traces the path of an imaginary packet through switch. Both forms require switch, the switch on which the packet arrived (one of
those listed by ofproto/list). The first form specifies a packet's contents explicitly:
priority
Packet QoS priority. Use 0 if QoS is not setup.
tun_id The tunnel ID on which the packet arrived. Use 0 if the packet did not arrive through a tunnel.
in_port
The OpenFlow port on which the packet arrived. Use 65534 if the packet arrived on OFPP_LOCAL, the local port.
packet A sequence of hex digits specifying the packet's contents. 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-tcpun-
dump(1) utilities provide easier ways.
The second form specifies the packet's contents implicitly:
odp_flow
A flow in the form printed by ovs-dpctl(8)'s dump-flows command. This is not an OpenFlow flow: besides other differences, it
never contains wildcards. ovs-vswitchd generates an arbitrary packet that has the specified odp_flow.
ovs-vswitchd will respond with extensive information on how the packet would be handled if it were to be received. The packet will
not actually be sent, but side effects such as MAC learning will occur.
ofproto/trace switch odp_flow
Traces the path of a packet in an imaginary flow through switch. The arguments are:
switch The switch on which the packet arrived (one of those listed by ofproto/list).
odp_flow
A flow in the form printed by ovs-dpctl(8)'s dump-flows command. This is not an OpenFlow flow: besides other differences, it
never contains wildcards.
ovs-vswitchd will respond with extensive information on how a packet in odp_flow would be handled if it were received by switch. No
packet will actually be sent. Some side effects may occur, but MAC learning in particular will not.
This form of ofproto/trace cannot determine the complete set of datapath actions in some corner cases. If the results say that this
is the case, rerun ofproto/trace supplying a packet in the flow to get complete results.
VLOG COMMANDS
These commands manage ovs-vswitchd's logging settings.
vlog/set module[:facility[:level]]
Sets the logging level for module in facility to level:
o module may be any valid module name (as displayed by the --list action on ovs-appctl(8)), or the special name ANY to set the
logging levels for all modules.
o facility may be syslog, console, or file to set the levels for logging to the system log, the console, or a file respec-
tively, or ANY to set the logging levels for both facilities. If it is omitted, facility defaults to ANY.
The log level for the file facility has no effect unless ovs-vswitchd was invoked with the --log-file option.
o level must be one of off, emer, err, warn, info, or dbg, designating the minimum severity of a message for it to be logged.
If it is omitted, level defaults to dbg.
vlog/set PATTERN:facility:pattern
Sets the log pattern for facility 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/reopen
Causes ovs-vswitchd to close and reopen its log file. (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.
STRESS OPTION COMMANDS
These command manage stress options, which allow developers testing Open vSwitch to trigger behavior that otherwise would occur only in
corner cases. Developers and testers can thereby more easily discover bugs that would otherwise manifest only rarely or nondeterministi-
cally. Stress options may cause surprising behavior even when they do not actually reveal bugs, so they should only be enabled as part of
testing Open vSwitch.
stress/enable
stress/disable
All stress options are disabled by default. Use stress/enable to enable stress options and stress/disable to disable them.
stress/list
Lists and describes the available stress options and their settings in tabular form. The columns in the table are:
NAME A single-word identifier for the option, used to identify stress options to stress/set.
DESCRIPTION
A description for a person unfamiliar with the detailed internals of the code what behavior the option affects.
PERIOD Currently configured trigger period. If the stress option is disabled, this is disabled. Otherwise this is a number giving
the number of occurrences of the event between activations of the stress option triggers.
MODE If the stress option is disabled, this is n/a. Otherwise it is periodic if the stress option triggers after exactly the
period, or random if it triggers randomly but on average after the number of occurrences specified by the period.
COUNTER
If the stress option is disabled, this is n/a. Otherwise it is the number of occurrences of the event before the next time
the stress option triggers.
HITS The number of times that this stress option has triggered since this program started.
RECOMMENDED
A suggested period for a person unfamiliar with the internals. It should put reasonable stress on the system without crip-
pling it.
MINIMUM
MAXIMUM
Minimum and maximum values allowed for the period.
DEFAULT
The default period, used when stress options have been enabled (with stress/enable) but this particular stress option has not
been specifically configured (with stress/set). It is disabled if the option is disabled by default. It is nonzero for
options that can be left on at low levels without noticeable impact to the end user.
stress/set option period [random|periodic]
Sets the period at which stress option triggers to period. A period of 0 disables option. Specify random to make the option trig-
ger randomly with an average period of period, or periodic to trigger exactly every period events; the latter is the default.
If stress options have not been enabled with stress/enable, this command has no effect.
SEE ALSO
ovs-appctl(8), ovs-brcompatd(8), ovsdb-server(1), INSTALL.Linux in the Open vSwitch distribution.
Open vSwitch June 2009 ovs-vswitchd(8)