Provided by: openvswitch-common_3.3.4-0ubuntu0.24.04.1_amd64 
NAME
ovs-appctl - utility for configuring running Open vSwitch daemons
SYNOPSIS
ovs-appctl [--target=target | -t target] [--timeout=secs | -T secs] command [arg ...]
ovs-appctl --help
ovs-appctl --version
DESCRIPTION
Open vSwitch daemons accept certain commands at runtime to control their behavior and query their
settings. Every daemon accepts a common set of commands documented under Common Commands below. Some
daemons support additional commands documented in their own manpages. ovs-vswitchd in particular accepts
a number of additional commands documented in ovs-vswitchd(8).
The ovs-appctl program provides a simple way to invoke these commands. The command to be sent is
specified on ovs-appctl’s command line as non-option arguments. ovs-appctl sends the command and prints
the daemon’s response on standard output.
In normal use only a single option is accepted:
• -t target or --target=target
Tells ovs-appctl which daemon to contact.
If target begins with / it must name a Unix domain socket on which an Open vSwitch daemon is listening
for control channel connections. By default, each daemon listens on a Unix domain socket in the rundir
(e.g. /run) named <program>.<pid>.ctl, where <program> is the program’s name and <pid> is its process
ID. For example, if ovs-vswitchd has PID 123, it would listen on ovs-vswitchd.123.ctl.
Otherwise, ovs-appctl looks in the rundir for a pidfile, that is, a file whose contents are the process
ID of a running process as a decimal number, named target.pid. (The --pidfile option makes an Open
vSwitch daemon create a pidfile.) ovs-appctl reads the pidfile, then looks in the rundir for a Unix
socket named target.<pid>.ctl, where <pid> is replaced by the process ID read from the pidfile, and
uses that file as if it had been specified directly as the target.
On Windows, target can be an absolute path to a file that contains a localhost TCP port on which an
Open vSwitch daemon is listening for control channel connections. By default, each daemon writes the
TCP port on which it is listening for control connection into the file <program>.ctl located inside the
rundir. If target is not an absolute path, ovs-appctl looks in the rundir for a file named target.ctl.
The default target is ovs-vswitchd.
• -T secs or --timeout=secs
By default, or with a secs of 0, ovs-appctl waits forever to connect to the daemon and receive a
response. This option limits runtime to approximately secs seconds. If the timeout expires,
ovs-appctl exits with a SIGALRM signal.
COMMON COMMANDS
Every Open vSwitch daemon supports a common set of commands, which are documented in this section.
General Commands
These commands display daemon-specific commands and the running version. Note that these commands are
different from the --help and --version options that return information about the ovs-appctl utility
itself.
• list-commands
Lists the commands supported by the target.
• version
Displays the version and compilation date of the target.
Logging Commands
Open vSwitch has several log levels. The highest-severity log level is:
• off
No message is ever logged at this level, so setting a logging destination’s log level to off disables
logging to that destination.
The following log levels, in order of descending severity, are available:
• emer
A major failure forced a process to abort.
• err
A high-level operation or a subsystem failed. Attention is warranted.
• warn
A low-level operation failed, but higher-level subsystems may be able to recover.
• info
Information that may be useful in retrospect when investigating a problem.
• dbg
Information useful only to someone with intricate knowledge of the system, or that would commonly cause
too-voluminous log output. Log messages at this level are not logged by default.
Every Open vSwitch daemon supports the following commands for examining and adjusting log levels:
• vlog/list
Lists the known logging modules and their current levels.
• vlog/list-pattern
Lists logging pattern used for each destination.
• 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 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.
On Windows platform, syslog is only useful if target was started with the --syslog-target option (it
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.
Case is not significant within spec.
Regardless of the log levels set for file, logging to a file will not take place unless the target
application was invoked with the --log-file option.
For compatibility with older versions of OVS, any is accepted within spec but it has no effect.
• vlog/set PATTERN:destination:pattern
Sets the log pattern for destination to pattern. Each time a message is logged to destination, pattern
determines the message’s formatting. Most characters in pattern are copied literally to the log, but
special escapes beginning with % are expanded as follows:
• %A
The name of the application logging the message, e.g. ovs-vswitchd.
• %B
The RFC5424 syslog PRI of the message.
• %c
The name of the module (as shown by ovs-appctl --list) logging the message.
• %d
The current date and time in ISO 8601 format (YYYY-MM-DD HH:MM:SS).
• %d{format}
The current date and time in the specified format, which takes the same format as the template
argument to strftime(3). As an extension, any # characters in format will be replaced by fractional
seconds, e.g. use %H:%M:%S.### for the time to the nearest millisecond. Sub-second times are only
approximate and currently decimal places after the third will always be reported as zero.
• %D
The current UTC date and time in ISO 8601 format (YYYY-MM-DD HH:MM:SS).
• %D{format}
The current UTC date and time in the specified format, which takes the same format as the template
argument to strftime(3). Supports the same extension for sub-second resolution as %d{...}.
• %E
The hostname of the node running the application.
• %m
The message being logged.
• %N
A serial number for this message within this run of the program, as a decimal number. The first
message a program logs has serial number 1, the second one has serial number 2, and so on.
• %n
A new-line.
• %p
The level at which the message is logged, e.g. DBG.
• %P
The program’s process ID (pid), as a decimal number.
• %r
The number of milliseconds elapsed from the start of the application to the time the message was
logged.
• %t
The subprogram name, that is, an identifying name for the process or thread that emitted the log
message, such as monitor for the process used for --monitor or main for the primary process or thread
in a program.
• %T
The subprogram name enclosed in parentheses, e.g. (monitor), or the empty string for the primary
process or thread in a program.
• %%
A literal %.
A few options may appear between the % and the format specifier character, in this order:
• -
Left justify the escape’s expansion within its field width. Right justification is the default.
• 0
Pad the field to the field width with 0 characters. Padding with spaces is the default.
• width
A number specifies the minimum field width. If the escape expands to fewer characters than width
then it is padded to fill the field width. (A field wider than width is not truncated to fit.)
The default pattern for console and file output is %D{%Y-%m-%dT %H:%M:%SZ}|%05N|%c|%p|%m; for syslog
output, %05N|%c|%p|%m.
Daemons written in Python (e.g. ovs-monitor-ipsec) do not allow control over the log pattern.
• vlog/set 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.
• vlog/close
Causes the daemon to close its log file, if it is open. (Use vlog/reopen to reopen it later.)
• vlog/reopen
Causes the daemon 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 if the target application was not invoked with the --log-file option.
OPTIONS
-h, --help
Prints a brief help message to the console.
-V, --version
Prints version information to the console.
SEE ALSO
ovs-appctl can control all Open vSwitch daemons, including ovs-vswitchd(8) and ovsdb-server(1).
AUTHOR
The Open vSwitch Development Community
COPYRIGHT
2016-2025, The Open vSwitch Development Community
3.3 May 02, 2025 OVS-APPCTL(8)