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What happens when systemd stops and restarts a unit?
Configures dependencies similar to Requires=, but limited to stopping and restarting of units. When systemd stops or restarts the units listed here, the action is propagated to this unit. Note that this is a one-way dependency — changes to this unit do not affect the listed units.
Which is the command to start a systemd service?
To start a systemd service, executing instructions in the service’s unit file, use the start command. If you are running as a non-root user, you will have to use sudo since this will affect the state of the operating system: sudo systemctl start application .service.
How to check if a service is active in systemd?
For instance, to check to see if a unit is currently active (running), you can use the is-active command: systemctl is-active application.service This will return the current unit state, which is usually active or inactive. The exit code will be “0” if it is active, making the result simpler to parse in shell scripts.
How to start a systemd service as a non-root user?
To start a systemd service, executing instructions in the service’s unit file, use the start command. If you are running as a non-root user, you will have to use sudo since this will affect the state of the operating system:
Why are dependency failures a flaw in systemd?
In my opinion, not having a way to handle dependency failures is a flaw in systemd. It seems like the sort of thing that could be scripted and put into a cronjob pretty easily. The basic logic would go something like this check to see if both service a and b as well as dependencies are running/in a valid state.
When to jump to a new service in systemd?
Jump should only occur if you are confident in the restart of services and dependencies will have a high likelihood of working, otherwise there is the potential for a loop.
What happens when a service is stopped in Linux?
This not only means a unit bound to another unit that suddenly enters inactive state, but also one that is bound to another unit that gets skipped due to a failed condition check (such as ConditionPathExists=, ConditionPathIsSymbolicLink=, … — see below) will be stopped, should it be running.