StartExecPost calling the service itself

iAmoric

4/5/24, 3:44 PM

I have a service defined as bellow:

Unit]
Description=My Service
After=network.target

[Service]
ExecStart=/usr/local/bin/myservice
KillMode=process
Restart=on-failure
ExecStartPost=/usr/local/bin/script.sh

[Install]
WantedBy=multi-user.target

and script.sh contains commands like:

while ! $(systemctl is-active --quiet myservice) ; do echo "waiting.."; sleep 5; done

(and other calls to the service)

The problem is that it doesn't work. I think it's a chicken-and-egg issue. I'm waiting for the service to be up in the service start itself. This obviously can't work.

So my question is:

How can I run script.sh automatically when myservice is up?

Thanks

1 + 1

linux

service

systemd

systemctl

Ginnungagap

4/6/24, 9:12 PM

You're trying to use `ExecStartPost` with a service that doesn't play nice since it doesn't notify systemd when it has finished starting up, you're most likely stuck with trying whatever it is you need `ExecStartPost` until it works.

Score:0

Server

asktyagi

4/5/24, 4:21 PM

From manual

ExecStartPost= commands are only run after the commands specified in ExecStart= have been invoked successfully, as determined by Type= (i.e. the process has been started for Type=simple or Type=idle, the last ExecStart= process exited successfully for Type=oneshot, the initial process exited successfully for Type=forking, "READY=1" is sent for Type=notify/Type=notify-reload, or the BusName= has been taken for Type=dbus).

So ExecStartPost will executed only after ExecStart= have been invoked successfully.

Your script doesn't work may be due to wrong options choose in unit file.

+ 1

iAmoric

4/5/24, 8:12 PM

I investigated a bit more. Actually, having service in `running` state is not enough. The service needs to start a server and listen on port X. This can take a bit of time. Thus, ExecStartPost starts too quickly, before the server to be started. What I don't understand is that I tool this in account in my script.sh (wait for port to be open) but it's waiting forever

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: StartExecPost calling the service itself

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