How to use Systemd to restart a service when down? [closed]

If you are using a systemd service file to start your service, then add the lines below to your service file from where you are starting your service:

[Service]Type=simpleExecStart=here will be your service executable nameRestart=alwaysRestartSec=0

• Restart=

  Configures whether the service shall be restarted when the service process exits, is killed, or a timeout is reached. Takes one of the following values: no, on-success, on-failure, on-abnormal, on-watchdog, on-abort or always. If set to no (the default).

• RestartSec=

  Configures the time to sleep before restarting a service (as configured with Restart=). Takes a unit-less value in seconds.

These two options have to be under the [Service] tag in a service file.

I have used monit monit for this. A post at askfedoraproject suggests to me that this is still a good way to monitor processes and automatically restart them.

It provides good granular configuration of the monitoring functions, how to decide if a process has failed, and actions to be taken to recover it.

Systemctl - System and Service manager for linux systems

Basics about systemd:Features:1.Parallel startup of system service at boot time2.On demand activation of daemons3.Dependecy based service control logic

* limited support at runlevel* panic is not support panic command(systemctl no custom commands)* systemctl can only communicate with services which are started by systemd* sysd stop only running services* system services don't inherit any context like HOME or PATH variable* All services subject to default timeout of 5 minutes can be configured.These prevents from system to freeze in case of some application stop to respond.

Systemd units: service , path, mount, snapshot, swap, timer, device etcUnit TypeFile ExtensionDescriptionService unit.serviceA system service.Target unit.targetA group of systemd units.Automount unit.automountA file system automount point.Device unit.deviceA device file recognized by the kernel.Mount unit.mountA file system mount point.Path unit.pathA file or directory in a file system.Scope unit.scopeAn externally created process.Slice unit.sliceA group of hierarchically organized units that manage system processes.Snapshot unit.snapshotA saved state of the systemd manager.Socket unit.socketAn inter-process communication socket.Swap unit.swapA swap device or a swap file.Timer unit.timerA systemd timer.

unit file's Filelocation: /etc/systemd/system

Conf file: /etc/systemd/system.conf

Systemd provides a lot of functionallity basically you can control all the resouces of linux system that gives you give a lot of functionality.We are focussing on managing system service in this article.

for more details: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/system_administrators_guide/chap-managing_services_with_systemd

MANAGING SYSTEM SERVICES:systemctlDescriptionsystemctl start name.serviceStarts a service.systemctl stop name.serviceStops a service.systemctl restart name.serviceRestarts a service.systemctl try-restart name.serviceRestarts a service only if it is running.systemctl reload name.serviceReloads configuration.systemctl status name.servicesystemctl is-active name.serviceChecks if a service is running.systemctl list-units --type service --allDisplays the status of all services.systemctlDescriptionsystemctl enable name.serviceEnables a service.systemctl disable name.serviceDisables a service.systemctl status name.servicesystemctl is-enabled name.serviceChecks if a service is enabled.systemctl list-unit-files --type serviceLists all services and checks if they are enabled.systemctl list-dependencies --afterLists services that are ordered to start before the specified unit.systemctl list-dependencies --beforeLists services that are ordered to start after the specified unit.