I have 2 services a.service and b.service. a.service is shown
[Unit] Description=My service [Service] Type=forking ExecStart=/bin/sh /home/admin/run.sh Restart=on-failure [Install] WantedBy=multi-user.target,
b.service
[Unit] Description=My service [Service] Type=forking ExecStart=/bin/sh $HOME/theFolder/run.sh Restart=on-failure [Install] WantedBy=multi-user.target
Now, when i start b.service, i’m sure a.service will be started. During runtime, suddenly someone messes with /home/admin/run.sh and systemd is unable to start a.service (also systemctl status a.service shows failed as status). Now is there a option so that b.service can know that a.service is failed and it should stop/exit?
Advertisement
Answer
You want to add either BindsTo= or Requires= to your [Unit] section, as documented in man systemd.unit:
Requires= Configures requirement dependencies on other units. If this unit gets activated, the units listed here will be activated as well. If one of the other units gets deactivated or its activation fails, this unit will be deactivated. This option may be specified more than once or multiple space-separated units may be specified in one option in which case requirement dependencies for all listed names will be created. Note that requirement dependencies do not influence the order in which services are started or stopped. This has to be configured independently with the After= or Before= options. If a unit foo.service requires a unit bar.service as configured with Requires= and no ordering is configured with After= or Before=, then both units will be started simultaneously and without any delay between them if foo.service is activated. Often, it is a better choice to use Wants= instead of Requires= in order to achieve a system that is more robust when dealing with failing services.
BindsTo= Configures requirement dependencies, very similar in style to Requires=, however in addition to this behavior, it also declares that this unit is stopped when any of the units listed suddenly disappears. Units can suddenly, unexpectedly disappear if a service terminates on its own choice, a device is unplugged or a mount point unmounted without involvement of systemd.