Eu quero executar algum script quando um serviço falhar. A coisa mais próxima que vejo é a opção FailureAction= (sob [Service] section), mas ela oferece apenas comandos de reinicialização.
Há uma diretiva OnFailure= na seção [Unit] , documentada em systemd unidade (5) . É definido da seguinte forma:
A space-separated list of one or more units that are activated when this unit enters the "failed" state.
(Também existe uma diretiva OnFailureJobMode= na mesma seção que permite definir o modo de trabalho para ativar OnFailure = unidades.)
Você também pode usar ExecStopPost para executar um comando diretamente em vez de iniciar uma unidade.
Eu não estava feliz com a configuração OnFailure , então continuei procurando e encontrei ExecStopPost .
O exemplo real a seguir, se a tarefa principal falhar, o systemd executará um comando git .
[Unit]
Description=SRI Dispenser Server
ConditionPathExists=|/usr/bin/
After=sri-boot-dsp.service
[Service]
WorkingDirectory=/usr/share/sri/configurations/transmitter
User=root
# This is task to run when this service starts
ExecStart=/usr/bin/python -m sri.DispenserServer
# If any of the ExecStart tasks fail, then ExecStopPost will run
ExecStopPost=/bin/git checkout -- .
Restart=always
RestartSec=10
KillSignal=SIGKILL
[Install]
WantedBy=multi-user.target
ExecStopPost= Additional commands that are executed after the service is stopped. This includes cases where the commands configured in ExecStop= were used, where the service does not have any ExecStop= defined, or where the service exited unexpectedly. This argument takes multiple command lines, following the same scheme as described for ExecStart=. Use of these settings is optional. Specifier and environment variable substitution is supported. Note that – unlike ExecStop= – commands specified with this setting are invoked when a service failed to start up correctly and is shut down again.
It is recommended to use this setting for clean-up operations that shall be executed even when the service failed to start up correctly. Commands configured with this setting need to be able to operate even if the service failed starting up half-way and left incompletely initialized data around. As the service's processes have been terminated already when the commands specified with this setting are executed they should not attempt to communicate with them.
Note that all commands that are configured with this setting are invoked with the result code of the service, as well as the main process' exit code and status, set in the $SERVICE_RESULT, $EXIT_CODE and $EXIT_STATUS environment variables, see systemd.exec(5) for details.
Tags systemd