Purpose:
You can create a failure script that is executed when syslog-ng OSE terminates abnormally, that is, when it exits with a non-zero exit code. For example, you can use this script to send an automatic email notification.
Prerequisites:
The failure script must be the following file: /opt/syslog-ng/sbin/syslog-ng-failure, and must be executable.
To create a sample failure script, complete the following steps.
Steps:
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Create a file named /opt/syslog-ng/sbin/syslog-ng-failure with the following content:
#!/usr/bin/env bash cat >>/tmp/test.txt <<EOF $(date) Name............$1 Chroot dir......$2 Pid file dir....$3 Pid file........$4 Cwd.............$5 Caps............$6 Reason..........$7 Argbuf..........$8 Restarting......$9 EOF
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Make the file executable: chmod +x /opt/syslog-ng/sbin/syslog-ng-failure
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Run the following command in the /opt/syslog-ng/sbin directory: ./syslog-ng --process-mode=safe-background; sleep 0.5; ps aux | grep './syslog-ng' | grep -v grep | awk '{print $2}' | xargs kill -KILL; sleep 0.5; cat /tmp/test.txt
The command starts syslog-ng OSE in safe-background mode (which is needed to use the failure script) and then kills it. You should see that the relevant information is written into the /tmp/test.txt file, for example:
Thu May 18 12:08:58 UTC 2017 Name............syslog-ng Chroot dir......NULL Pid file dir....NULL Pid file........NULL Cwd.............NULL Caps............NULL Reason..........signalled Argbuf..........9 Restarting......not-restarting
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You should also see messages similar to the following in system syslog. The exact message depends on the signal (or the reason why syslog-ng OSE stopped):
May 18 13:56:09 myhost supervise/syslog-ng[10820]: Daemon exited gracefully, not restarting; exitcode='0' May 18 13:57:01 myhost supervise/syslog-ng[10996]: Daemon exited due to a deadlock/signal/failure, restarting; exitcode='131' May 18 13:57:37 myhost supervise/syslog-ng[11480]: Daemon was killed, not restarting; exitcode='9'
The failure script should run on every non-zero exit event.