Deploying Spring Boot app as a Linux service

spring_app_as_linux_service.gist

This method uses the modern systemd way to run a Java JAR (i.e. a Spring Boot app) as a daemon as opposed to using the older method of using init.d (SystemV). Using the "&" symbol to run the process in the background isn't sufficient b/c the process will be shut down when the terminal closes (or when you exit your SSH session if remoting in to the machine). Using the "nohup" command is another option, but that is like the "poor man's way" of running a service: doesn't restart on machine reboot; program ignores interrupts, quit signals, and hangups. For more info see: https://stackoverflow.com/questions/958249/whats-the-difference-between-nohup-and-a-daemon .

Anyways, to create a Linux daemon the systemd way:

Create a service file in /etc/systemd/system. Let's call it javaservice.service. Let the contents be:

[Unit]
Description=My Java Service

[Service]
User=someuser
# The configuration file application.properties should be here:
WorkingDirectory=/home/myuser/my-apps 
ExecStart=/usr/bin/java -Xmx256m -jar application.jar --server.port=9900
SuccessExitStatus=143
TimeoutStopSec=10
Restart=on-failure
RestartSec=5

[Install]
WantedBy=multi-user.target


sudo systemctl daemon-reload	<== notifies systemd of the new service file
sudo systemctl enable javaservice.service		<== enable it so it runs on boot
// javaservice.service will be added to the dir /etc/systemd/system/multi-user.target.wants. This dir indicates what services to start on boot

sudo systemctl start javaservice
sudo systemctl status javaservice   <== check that the service is running fine