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gcb
Asked: 2024-08-01 11:06:29 +0800 CST

Can systemd execute a command *before* a restart?

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This is not about ExecStartPre

One use case when tweaking services is to test a config file before restarting the service.

for example.

$ vim /etc/nginx.conf
$ nginx -t && restart_nginx

the equivalent with systemd is to still having to remember the check before issuing a restart.

Is there something that prevents that very-likely human error? something like ExecRestartStopPre? That is, something it will execute before the stop step of a restart?

systemd

1 Answers

  1. Best Answer

    I wonder if you should be using ExecReload in this case? Add something like this to your service unit:

    ExecReload=bash -c 'nginx -t && nginx -s reload'

    This will only send the reload (HUP) signal to nginx if the configuration check passes. Unlike restart, this doesn't perform a stop or start on the service.

    Instead of running running systemctl restart nginx, you would run systemctl reload nginx.

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