systemd-notify

Name

systemd-notify — Notify service manager about start-up completion and other daemon status changes

Synopsis

systemd-notify [OPTIONS...] [VARIABLE=VALUE...]

Description¶

systemd-notify may be called by daemon scripts to notify the init system about status changes. It can be used to send arbitrary information, encoded in an environment-block-like list of strings. Most importantly it can be used for start-up completion notification.

This is mostly just a wrapper around sd_notify() and makes this functionality available to shell scripts. For details see sd_notify(3).

The command line may carry a list of environment variables to send as part of the status update.

Note that systemd will refuse reception of status updates from this command unless NotifyAccess=all is set for the service unit this command is called from.

Options¶

The following options are understood:

--ready¶: Inform the init system about service start-up completion. This is equivalent to systemd-notify READY=1. For details about the semantics of this option see sd_notify(3).
--pid=¶: Inform the init system about the main PID of the daemon. Takes a PID as argument. If the argument is omitted, the PID of the process that invoked systemd-notify is used. This is equivalent to systemd-notify MAINPID=$PID. For details about the semantics of this option see sd_notify(3).
--status=¶: Send a free-form status string for the daemon to the init systemd. This option takes the status string as argument. This is equivalent to systemd-notify STATUS=.... For details about the semantics of this option see sd_notify(3).
--booted¶: Returns 0 if the system was booted up with systemd, non-zero otherwise. If this option is passed, no message is sent. This option is hence unrelated to the other options. For details about the semantics of this option, see sd_booted(3).
--readahead=¶: Controls disk read-ahead operations. The argument must be a string, and either "cancel", "done" or "noreplay". For details about the semantics of this option see sd_readahead(3).
-h, --help¶: Print a short help text and exit.
--version¶: Print a short version string and exit.

Exit status¶

On success, 0 is returned, a non-zero failure code otherwise.

Example¶

Example 1. Start-up Notification and Status Updates

A simple shell daemon that sends start-up notifications after having set up its communication channel. During runtime it sends further status updates to the init system:

#!/bin/bash

mkfifo /tmp/waldo
systemd-notify --ready --status="Waiting for data..."

while : ; do
        read a < /tmp/waldo
        systemd-notify --status="Processing $a"

        # Do something with $a ...

        systemd-notify --status="Waiting for data..."
done