Manage Systemd Service

Create & Manage Systemd Service

Create a systemd service

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sudo vi /etc/systemd/system/<service-name>.service

Add the following content to the service file (.service)

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[Unit]
Description=<service-description>
After=network.target

[Service]
Type=simple
TimeoutStartSec=30
User=<user-name>
Group=<group-name>
WorkingDirectory=<working-directory>
ExecStart=<command-to-start-service>
Restart=always
RestartSec=30s

[Install]
WantedBy=multi-user.target

Cheatsheet

Name	Description	Value
Description	Description of the service
After	The service will be started after the network is up
Type	The type of service	simple, forking
TimeoutStartSec	The time to wait before starting the service
User	The user to run the service
Group	The group to run the service
WorkingDirectory	The working directory of the service	Eg. The source code directory.
ExecStart	The command to start the service
Restart	Restart the service if it crashes
RestartSec	The time to wait before restarting the service
WantedBy	The target to start the service

Eg. A sample service file for a Golang app

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[Unit]
Description=Hain
Documentation=https://hainguyen.dev/

[Service]
Type=forking
User=root
Group=root
TimeoutStartSec=0
Restart=on-failure
RestartSec=30s
#ExecStartPre=
Environment=GOPATH=/root/go
WorkingDirectory=/root/go/src/github.com/hain/src
ExecStart=/bin/bash script/run.sh
SyslogIdentifier=Diskutilization
#ExecStop=

[Install]
WantedBy=multi-user.target

Enable the service

1

sudo systemctl enable <service-name>.service

Start the service

1

sudo systemctl start <service-name>.service

Stop the service

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sudo systemctl stop <service-name>.service

Restart the service

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sudo systemctl restart <service-name>.service

Check the service status

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sudo systemctl status <service-name>.service

Delete the service

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sudo systemctl disable <service-name>.service
sudo rm /etc/systemd/system/<service-name>.service

Troubleshooting

Check the service logs

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sudo journalctl -u <service-name>.service

Retain the logs for a specific time

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sudo journalctl --vacuum-time=1d

Retain the logs for a specific size

1

sudo journalctl --vacuum-size=1G

Cheatsheet

Name	Description
journalctl	The command to check the logs
-u	The service name
-f	Follow the logs
-n	The number of logs to show
-o	The output format
-p	The priority of the logs
–vacuum-time	The time to keep the logs
–vacuum-size	The size to keep the logs