path: root/utilities/ovs-ctl.8

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.TH ovs\-ctl 8 "June 2011" "Open vSwitch" "Open vSwitch Manual"
.ds PN ovs\-ctl
.
.SH NAME
ovs\-ctl \- OVS startup helper script
.
.SH SYNOPSIS
\fBovs\-ctl\fR [\fB\-\-system\-id=random\fR | \fIuuid\fR]
[\fIoptions\fR] \fBstart
.br
\fBovs\-ctl stop
.br
\fBovs\-ctl status
.br
\fBovs\-ctl version
.br
\fBovs\-ctl force-reload-kmod
.br
\fBovs\-ctl help \fR| \fB\-h \fR| \fB\-\-help
.br
\fBovs\-ctl \-\-version
.
.SH DESCRIPTION
.
.PP
The \fBovs\-ctl\fR program starts, stops, and checks the status of
Open vSwitch daemons.  It is not meant to be invoked directly by
system administrators but to be called internally by system startup
scripts.
.
.PP
Each of \fBovs\-ctl\fR's commands is described separately below.
.
.SH "The ``start'' command"
.
.PP
The \fBstart\fR command starts Open vSwitch.  It performs the
following tasks:
.
.IP 1.
Loads the Open vSwitch kernel module.  If this fails, and the Linux
bridge module is loaded but no bridges exist, it tries to unload the
bridge module and tries loading the Open vSwitch kernel module again.
(This is because the Open vSwitch kernel module cannot coexist with
the Linux bridge module before 2.6.37.)
.
.PP
The \fBstart\fR command skips the following steps if
\fBovsdb\-server\fR is already running:
.IP 2.
If the Open vSwitch database file does not exist, it creates it.
If the database does exist, but it has an obsolete version, it
upgrades it to the latest schema.
.
.IP 3.
Starts \fBovsdb-server\fR.
.
.IP 4.
Initializes a few values inside the database.
.
.IP 5.
If the \fB\-\-delete\-bridges\fR option was used, deletes all of the
bridges from the database.
.
.PP
The \fBstart\fR command skips the following step if
\fBovs\-vswitchd\fR is already running:
.IP 6.
Starts \fBovs\-vswitchd\fR.
.
.SS "Options"
.PP
Several command-line options influence the \fBstart\fR command's
behavior.  Some form of the following option should ordinarily be
specified:
.
.IP "\fB\-\-system\-id=\fIuuid\fR"
.IQ "\fB\-\-system\-id=random\fR"
This specifies a unique system identifier to store into
\fBexternal-ids:system-id\fR in the database's \fBOpen_vSwitch\fR
table.  Remote managers that talk to the Open vSwitch database server
over network protocols use this value to identify and distinguish Open
vSwitch instances, so it should be unique (at least) within OVS
instances that will connect to a single controller.
.IP
When \fBrandom\fR is specified, \fBovs\-ctl\fR will generate a random
ID that persists from one run to another (stored in a file).  When
another string is specified \fBovs\-ctl\fR uses it literally.
.
.PP
On systems that have the \fBlsb_release\fR program, \fBovs\-ctl\fR
chooses reasonable defaults for the following options.  Other systems
should specify values:
.
.IP "\fB\-\-system\-type=\fItype\fR"
.IQ "\fB\-\-system\-version=\fIversion\fR"
Sets the value to store in the \fBsystem-type\fR and
\fBsystem-version\fR columns, respectively, in the database's
\fBOpen_vSwitch\fR table.  Remote managers may use these values to
determine the kind of system to which they are connected (primarily
for display to human administrators).
.
.PP
The following options are also likely to be useful:
.
.IP "\fB\-\-external\-id=\(dq\fIname\fB=\fIvalue\fB\(dq"
Sets \fBexternal-ids:\fIname\fR to \fIvalue\fR in the database's
\fBOpen_vSwitch\fR table.  Specifying this option multiple times adds
multiple key-value pairs.
.
.IP "\fB\-\-delete\-bridges\fR"
Ordinarily Open vSwitch bridges persist from one system boot to the
next, as long as the database is preserved.  Some environments instead
expect to re-create all of the bridges and other configuration state
on every boot.  This option supports that, by deleting all Open
vSwitch bridges after starting \fBovsdb\-server\fR but before starting
\fBovs\-vswitchd\fR.
.
.PP
The following options are less important:
.
.IP "\fB\-\-daemon-cwd=\fIdirectory\fR"
Specifies the current working directory that the OVS daemons should
run from.  The default is \fB/\fR (the root directory) if this option
is not specified.  (This option is useful because most systems create
core files in a process's current working directory and because a file
system that is in use as a process's current working directory cannot
be unmounted.)
.
.IP "\fB\-\-no\-force\-corefiles\fR"
By default, \fBovs\-ctl\fR enables core dumps for the OVS daemons.
This option disables that behavior.
.
.IP "\fB\-\-no\-mlockall\fR"
By default \fBovs\-ctl\fR passes \fB\-\-mlockall\fR to
\fBovs\-vswitchd\fR, requesting that it lock all of its virtual
memory, preventing it from being paged to disk.  This option
suppresses that behavior.
.
.IP "\fB\-\-ovsdb\-server\-priority=\fIniceness\fR"
.IQ "\fB\-\-ovs\-vswitchd\-priority=\fIniceness\fR"
Sets the \fBnice\fR(1) level used for \fBovsdb\-server\fR and
\fBovs\-vswitchd\fR, respectively.  Both default to \fB\-10\fR.
.
.PP
The following options control file locations.  They should only be
used if the default locations cannot be used.  See \fBFILES\fR, below,
for more information.
.
.IP "\fB\-\-db\-file=\fIfile\fR"
Overrides the file name for the OVS database.
.
.IP "\fB\-\-db\-sock=\fIsocket\fR"
Overrides the file name for the Unix domain socket used to connect to
\fBovsdb\-server\fR.
.
.IP "\fB\-\-db\-schema=\fIschema\fR"
Overrides the file name for the OVS database schema.
.
.SH "The ``stop'' command"
.
.PP
The \fBstart\fR command shuts down Open vSwitch.  If
\fBovs\-vswitchd\fR is running, kills it and waits for it to
terminate, then it does the same for \fBovsdb\-server\fR.
.
.PP
This command does nothing and finishes successfully if the OVS daemons
aren't running.
.
.SH "The ``status'' command"
.
.PP
The \fBstatus\fR command checks whether the OVS daemons are running
and prints messages with that information.  It exits with status 0 if
the daemons are running, 1 otherwise.
.
.SH "The ``version'' command"
.
.PP
The \fBversion\fR command runs \fBovsdb\-server \-\-version\fR and
\fBovs\-vswitchd \-\-version\fR.
.
.SH "The ``force\-reload\-kmod'' command"
.
.PP
The \fBforce\-reload\-kmod\fR command allows upgrading the Open
vSwitch kernel module without rebooting.  It performs the following
tasks:
.
.IP 1.
Gets a list of OVS ``internal'' interfaces, that is, network devices
implemented by Open vSwitch.  The most common examples of these are
bridge ``local ports''.
.
.IP 2.
Stops the Open vSwitch daemons, as if by a call to \fBovs\-ctl
stop\fR.
.
.IP 3.
Saves the kernel configuration state of the OVS internal interfaces
listed in step 1, including IP and IPv6 addresses and routing table
entries.
.
.IP 4.
Unloads the Open vSwitch kernel module.
.
.IP 5.
Starts OVS back up, as if by a call to \fBovs\-ctl start\fR.  This
reloads the kernel module and restarts the OVS daemons.
.
.IP 6.
Restores the kernel configuration state that was saved in step 3.
.
.PP
The steps above are often enough to hot-upgrade a new kernel module
with only a few seconds of downtime.  DHCP is a common problem: if the
ISC DHCP client is running on an OVS internal interface, then it will
have to be restarted after completing the above procedure.
.
.PP
Because \fBforce\-kmod\-reload\fR internally stops and starts OVS, it
accepts all of the options accepted by the \fBstart\fR command.
.
.SS "The ``help'' command"
.
Prints a usage message and exits successfully.
.
.SH "EXIT STATUS"
.
\fBovs\-ctl\fR exits with status 0 on success and nonzero on failure.
The \fBstart\fR command is considered to succeed if OVS is already
started; the \fBstop\fR command is considered to succeed if OVS is
already stopped.
.
.SH "ENVIRONMENT"
.
The following environment variables affect \fBovs\-ctl\fR:
.
.IP "\fBPATH\fR"
\fBovs\-ctl\fR does not hardcode the location of any of the programs
that it runs.  \fBovs\-ctl\fR will add the \fIsbindir\fR and
\fIbindir\fR that were specified at \fBconfigure\fR time to
\fBPATH\fR, if they are not already present.
.
.IP "\fBOVS_LOGDIR\fR"
.IQ "\fBOVS_RUNDIR\fR"
.IQ "\fBOVS_SYSCONFDIR\fR"
.IQ "\fBOVS_PKGDATADIR\fR"
.IQ "\fBOVS_BINDIR\fR"
.IQ "\fBOVS_SBINDIR\fR"
Setting one of these variables in the environment overrides the
respective \fBconfigure\fR option, both for \fBovs\-ctl\fR itself and
for the other Open vSwitch programs that it runs.
.
.SH "FILES"
.
\fBovs\-ctl\fR uses the following files:
.
.IP "\fBovs\-lib.sh"
Shell function library used internally by \fBovs\-ctl\fR.  It must be
installed in the same directory as \fBovs\-ctl\fR.
.
.IP "\fIlogdir\fB/\fIdaemon\fB.log\fR"
Per-daemon logfiles.
.
.IP "\fIrundir\fB/\fIdaemon\fB.pid\fR"
Per-daemon pidfiles to track whether a daemon is running and with what
process ID.
.
.IP "\fIpkgdatadir\fB/vswitch.ovsschema\fR"
The OVS database schema used to initialize the database (use
\fB\-\-db\-schema to override this location).
.
.IP "\fIsysconfdir\fB/openvswitch/conf.db\fR"
The OVS database (use \fB\-\-db\-file\fR to override this location).
.
.IP "\fIrundir\fB/openvswitch/db.sock\fR"
The Unix domain socket used for local communication with
\fBovsdb\-server\fR (use \fB\-\-db\-sock\fR to override this
location).
.
.IP "\fIsysconfdir\fB/openvswitch/system-id.conf\fR"
The persistent system UUID created and read by
\fB\-\-system\-id=random\fR.
.
.SH "EXAMPLE"
.
.PP
The files \fBdebian/openvswitch\-switch.init\fR and
\fBxenserver/etc_init.d_openvswitch\fR in the Open vSwitch source
distribution are good examples of how to use \fBovs\-ctl\fR.
.
.SH "SEE ALSO"
.
\fBREADME\fR, \fBINSTALL.LINUX\fR, \fBovsdb\-server\fR(8),
\fBovs\-vswitchd\fR(8).