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99 lines
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99 lines
3.5 KiB
Text
[#converting-sysvinit-services]
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= Converting SysVinit services to systemd
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Older versions of Fedora use SysVinit scripts to manage services. This section provides some guidelines on how to convert a SysVinit script to a _systemd_ equivalent.
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[discrete]
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== Prerequisites
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* You are logged in as a user with administrator-level permissions.
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* You have a custom SysVinit script to convert to a _systemd_ configuration.
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[discrete]
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== Procedure
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. Identify the runlevels in your SysVinit script. This is usually defined with `chkconfig` directive in the commented section at the beginning of the script. For example, the following indicates the service is using runlevels 3, 4, and 5:
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----
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# chkconfig: 235 20 80
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----
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systemd uses targets instead of runlevels. Use the table in <<#converting-sysvinit-services>> to map the runlevels to targets. In this example, runlevels 2, 3, and 5 are all multi-user runlevels, so the _systemd_ service can use the following:
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----
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[Install]
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WantedBy=multi-user.target
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----
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If you enable the custom _systemd_ service to start at boot (`systemctl enable foo.service`), _systemd_ loads the service when loading the `multi-user.target` at boot time.
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. Identify the dependent services and targets. For example, if the custom service requires network connectivity, specify the `network.target` as a dependency:
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----
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[Unit]
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Description=My custom service
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After=network.target
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----
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. Identify the command used to start the service in the SysVinit script and convert this to the _systemd_ equivalent. For example, the script might contain a `start` function in the following format:
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[source,bash]
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----
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start() {
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echo "Starting My Custom Service..."
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/usr/bin/myservice -D
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}
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----
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In this example, the `/usr/bin/myservice` command is the custom service command set to daemonize with the `-D` option. Set the `ExecStart` parameter to use this command:
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----
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[Service]
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ExecStart=/usr/bin/myservice -D
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----
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. Check the SysVinit script to see if the service uses a special command to restart the service. For example, the script might contain a `reboot` function that reloads the service:
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[source,bash]
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----
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reboot() {
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echo "Reloading My Custom Service..."
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/usr/bin/myservice reload
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}
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----
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In this example, the `/usr/bin/myservice` command is the custom service command and reloads the service using the `reload` subcommand. Set the `ExecReload` parameter to use this command:
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----
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[Service]
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ExecReload=/usr/bin/myservice reload
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----
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Alternatively, you can omit `ExecReload` and use the default behavior, which kills the service and starts it again.
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. Check the SysVinit script to see if the service uses a special command to stop the service. For example, the script might contain a `stop` function that reloads the service:
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[source,bash]
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----
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reboot() {
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echo "Stopping My Custom Service..."
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/usr/bin/myservice shutdown
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}
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----
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In this example, the `/usr/bin/myservice` command is the custom service command and stop the service gracefully using the `shutdown` subcommand. Set the `ExecStop` parameter to use this command:
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----
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[Service]
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ExecStop=/usr/bin/myservice shutdown
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----
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Alternatively, you can omit `ExecStop` and use the default behavior, which kills the service.
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. Review the SysVinit script and identify any additional parameters or functions. Use _systemd_ parameters to replicate any identified SysVinit functions that might be relevant to your service.
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[discrete]
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== Related Information
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* See link:#common-service-parameters[Common service parameters] for more information about the parameters used in this procedure.
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