Linux Classroom notes 29/July/2026

systemd Service:

1. java appliaction:
   • java install sudo apt-get install openjdk-17-jdk -y
   • verify version: java -version
   • maven sudo apt-get install maven -y
   • mvn --version

spring petclinic build

git clone https://github.com/spring-projects/spring-petclinic.git cd spring-petclinic sudo mvn clean package -Dmaven.test.skip=true

Now check target folder:

mkdir /home/ubuntu/spring

sudo cp -rf /home/ubuntu/spring-petclinic/target/spring-petclinic-4.0.0-SNAPSHOT.jar /home/ubuntu/spring

sudo chown ubuntu:ubuntu /home/ubuntu/spring/spring-petclinic-4.0.0-SNAPSHOT.jar

java -jar jarfile-path

Why service: run application as background

benfits:

• auto start
• auto start after reboot
• Easy managment
• logging with jornalctl

systemctl cmds:

• sudo systemctl start <service name> – start application
• sudo systemctl status <service name> – status application
• sudo systemctl restart <service name> – manually restart application
• sudo systemctl enable <service name> – enable to run service after reboot
• sudo systemctl daemon-reload – need to any modification service file (reload service files)

[Unit]
Description=Spring PetClinic Application
Documentation=https://github.com/spring-projects/spring-petclinic.git
After=network.target

[Service]
WorkingDirectory=/home/ubuntu/spring
Environment=SPRING_PROFILES_ACTIVE=prod
Environment=JAVA_HOME=/usr/lib/jvm/java-17-openjdk-amd64
ExecStart=/usr/bin/java -jar /home/ubuntu/spring/spring-petclinic-4.0.0-SNAPSHOT.jar

Restart=always
RestartSec=10
User=ubuntu
Group=ubuntu

[Install]
WantedBy=multi-user.target