Custom systemd Unit and Unit File: Difference between revisions
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= | =Internal= | ||
* [[Systemd_Operations#Custom_systemd_Unit|systemd Operations]] | |||
* [[Systemd_Concepts#Create_a_Custom_Unit_File_for_a_Service|systemd Concepts]] | |||
* [[Minecraft]] | |||
=Overview= | |||
This article describes the procedure to configure an arbitrary service <code>minecraft</code> to be managed by <code>systemd</code>. It includes the creation of corresponding [[Systemd_Concepts#Unit_Files|unit file]] and <code>systemd</code> configuration to start and stop the service automatically at boot, respectively shutdown. | |||
=Create the Unit File= | |||
Create the <code>/etc/systemd/system/minecraft.service</code> unit file. As root: | |||
<syntaxhighlight lang='bash'> | |||
touch /etc/systemd/system/minecraft.service | |||
chmod 644 /etc/systemd/system/minecraft.service | |||
</syntaxhighlight> | |||
For more details on the location of the unit files, see: {{Internal|Systemd_Concepts#Unit_File_Location|systemd Concepts | Unit File Location}} | |||
=Configure the Unit File= | |||
==Process Started and Stopped by Auxiliary Scripts== | |||
This is common for Java programs, <code>/home/minecraft/minecraft-server/minecraft</code> is a wrapper script that starts the JVM and puts in background like this: | |||
<syntaxhighlight lang='bash'> | |||
java -server -jar ... > $(dirname $0)/logs/stdout-and-sterr.log 2>&1 & | |||
</syntaxhighlight> | |||
The unit file configuration is similar to: | |||
<syntaxhighlight lang='bash'> | |||
[Unit] | |||
Description=Minecraft service | |||
After=network.target | |||
[Service] | |||
Type=oneshot | |||
ExecStart=/home/minecraft/minecraft-server/minecraft start | |||
ExecStop=/home/minecraft/minecraft-server/minecraft stop | |||
RemainAfterExit=yes | |||
[Install] | |||
WantedBy=multi-user.target | |||
</syntaxhighlight> | |||
Also see: {{Internal|Systemd_Concepts#Type.3Doneshot|systemd Concepts | <tt>oneshot</tt>}} | |||
==Daemon Process that Forks and Creates Its Own PID File== | |||
<syntaxhighlight lang='bash'> | |||
[Unit] | |||
Description=MyService | |||
After=network.target | |||
=Internal= | [Service] | ||
ExecStart=/opt/myservice/bin/myservice | |||
Type=forking | |||
PIDFile=/var/run/myservice.pid | |||
[Install] | |||
WantedBy=multi-user.target | |||
</syntaxhighlight> | |||
Also see: {{Internal|Systemd_Concepts#Type.3Dforking|Systemd Concepts | <tt>forking</tt>}} | |||
=Notify <tt>systemd</tt> of the Existence of the New Unit File= | |||
<syntaxhighlight lang='bash'> | |||
systemctl daemon-reload | |||
</syntaxhighlight> | |||
<font color=darkkhaki>Is this really necessary? Why exactly? At this point the file is completely unknown to the system, it as not enabled.</font> | |||
For more details on <code>daemon-reload</code> see: {{Internal|Systemd_Concepts#Daemon_Reload|systemd Concepts | Daemon Reload}} | |||
=Enable at Boot= | |||
<syntaxhighlight lang='bash'> | |||
systemctl enable minecraft.service | |||
</syntaxhighlight> | |||
<syntaxhighlight lang='bash'> | |||
Created symlink from /etc/systemd/system/multi-user.target.wants/minecraft.service to /etc/systemd/system/minecraft.service. | |||
</syntaxhighlight> | |||
= | =Exercise the Service= | ||
<syntaxhighlight lang='bash'> | |||
systemctl start minecraft | |||
systemctl status minecraft | |||
systemctl restart minecraft | |||
systemctl stop minecraft | |||
</syntaxhighlight> | |||
Latest revision as of 03:03, 3 October 2023
Internal
Overview
This article describes the procedure to configure an arbitrary service minecraft to be managed by systemd. It includes the creation of corresponding unit file and systemd configuration to start and stop the service automatically at boot, respectively shutdown.
Create the Unit File
Create the /etc/systemd/system/minecraft.service unit file. As root:
touch /etc/systemd/system/minecraft.service
chmod 644 /etc/systemd/system/minecraft.service
For more details on the location of the unit files, see:
Configure the Unit File
Process Started and Stopped by Auxiliary Scripts
This is common for Java programs, /home/minecraft/minecraft-server/minecraft is a wrapper script that starts the JVM and puts in background like this:
java -server -jar ... > $(dirname $0)/logs/stdout-and-sterr.log 2>&1 &
The unit file configuration is similar to:
[Unit]
Description=Minecraft service
After=network.target
[Service]
Type=oneshot
ExecStart=/home/minecraft/minecraft-server/minecraft start
ExecStop=/home/minecraft/minecraft-server/minecraft stop
RemainAfterExit=yes
[Install]
WantedBy=multi-user.target
Also see:
Daemon Process that Forks and Creates Its Own PID File
[Unit]
Description=MyService
After=network.target
[Service]
ExecStart=/opt/myservice/bin/myservice
Type=forking
PIDFile=/var/run/myservice.pid
[Install]
WantedBy=multi-user.target
Also see:
Notify systemd of the Existence of the New Unit File
systemctl daemon-reload
Is this really necessary? Why exactly? At this point the file is completely unknown to the system, it as not enabled.
For more details on daemon-reload see:
Enable at Boot
systemctl enable minecraft.service
Created symlink from /etc/systemd/system/multi-user.target.wants/minecraft.service to /etc/systemd/system/minecraft.service.
Exercise the Service
systemctl start minecraft
systemctl status minecraft
systemctl restart minecraft
systemctl stop minecraft