ovn-appctl(8)

📦
version 26.09.0 · 16 versions
, in fedora 44

💖 ovn-appctl — the utility for configuring running OVN daemons 💖

okay bestie, listen. this is ovn-appctl, from the OVN Manual collection, and it's genuinely iconic. it's the little tool that lets you poke at OVN daemons while they're already running and ask them stuff. no restarting, no drama. let's get into it 🫶

✨ SYNOPSIS ✨

ovn-appctl [-target=target | -t target] [-T secs | -timeout=secs]
command [arg...]

ovn-appctl -help

ovn-appctl -version

🌸 DESCRIPTION 🌸

so here's the vibe: OVN daemons will accept certain commands at runtime to control their behavior and to query their settings. literally while they're running. every daemon accepts a common set of commands, and those are documented down in COMMON COMMANDS below. some daemons support extra commands on top of that, and those live in their own manpages. iykyk 💅

the ovn-appctl program is your simple little gateway to invoking those commands. the command you wanna send gets specified on ovn-appctl's command line as non-option arguments. then ovn-appctl sends the command and prints the daemon's response on standard output. that's it. that's the whole job. slay ✨

and for the record: ovn-appctl is the equivalent of the Open vSwitch ovs-appctl utility. same energy, different ecosystem 🦋

👑 COMMAND COMMANDS 👑

every OVN daemon supports a common set of commands, and they're all documented right here in this section. periodt.

🎀 General Commands

these commands display daemon-specific commands and the running version. note that these are different from the -help and -version options, which return information about the ovn-appctl utility itself. two different things, bestie, don't mix them up 🙈

  • list-commands — lists the commands supported by the target.
  • version — displays the version and compilation date of the target.

🧚 Logging Commands

OVN 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 hard stop. 💀
  • 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 OVN daemon supports the following commands for examining and adjusting log levels. go off 👑

  • 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, it 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 ovn-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.
    • 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.

  • 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. ovn-controller.
    • %B : the RFC5424 syslog PRI of the message.
    • %c : the name of the module (as shown by ovn-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.
  • - : pad the field to the field width with 0s. 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.

  • 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.

and that's the whole page, bestie 🎀 this one came from OVN 26.09.1, and yeah — ovn-appctl really is out here being its own whole manpage. go forth and query your daemons 💖✨🦋

📦 where this page comes from