🚀 How to Create a Service in Ubuntu Using systemd

🎯 Why Do We Create a Service in Ubuntu?

A service is a background process (daemon) that runs continuously, even after logging out or rebooting the system.

✅ Key Benefits of Creating a Service:

• 🏗 Automation & Startup Execution → Ensures apps start automatically on boot.
• 🔄 Process Management & Stability → Monitors and restarts failed applications.
• 🔐 Security & User Permissions → Runs services with restricted users.
• ⚙️ Standardized Control → Uses systemctl for easy management.

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🛠 Step-by-Step Guide to Creating a Service in Ubuntu

📌 Step 1: Prepare Your Script or Application

Before creating a service, ensure you have a script or application ready. For example, a simple bash script /opt/myapp/start.sh:

#!/bin/bash
echo "My service is running..."
while true; do
  sleep 60
done

Give it execution permissions:

chmod +x /opt/myapp/start.sh

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📌 Step 2: Create a systemd Service File

Create a new service file in /etc/systemd/system/:

sudo nano /etc/systemd/system/myapp.service

🔹 Add the following content:

[Unit]
Description=My Custom Application Service
After=network.target

[Service]
ExecStart=/opt/myapp/start.sh
WorkingDirectory=/opt/myapp
Restart=always
User=root
Group=root

[Install]
WantedBy=multi-user.target

🔍 Explanation:

• [Unit] → Defines metadata & dependencies.
• [Service] → Configures execution & restart behavior.
  • User=root → Runs the service as the root user. This means the service has full system privileges, which is not recommended for security-sensitive applications. Consider running under a non-root user if possible.
  • Group=root → Defines the group under which the service runs. Keeping it root means the service has administrative group access.
• [Install] → Enables auto-start at boot.

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📌 Step 3: Reload systemd & Start the Service

After creating the service file, reload systemd:

sudo systemctl daemon-reload

Start your service:

sudo systemctl start myapp

Check if it's running:

sudo systemctl status myapp

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📌 Step 4: Enable the Service to Start on Boot

To ensure the service starts automatically:

sudo systemctl enable myapp

Disable auto-start (if needed):

sudo systemctl disable myapp

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📌 Step 5: Managing the Service

Action	Command
✅ Start	sudo systemctl start myapp
⛔ Stop	sudo systemctl stop myapp
🔄 Restart	sudo systemctl restart myapp
🔎 Check Status	sudo systemctl status myapp
🔥 Check if Active	sudo systemctl is-active myapp
🚀 Check if Enabled at Boot	sudo systemctl is-enabled myapp

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📌 Step 6: View Logs of the Service

View historical logs:

sudo journalctl -u myapp --no-pager

📡 Real-time logs:

sudo journalctl -u myapp -f

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📌 Step 7: Remove the Service

To remove the service: 1️⃣ Stop & disable it:

sudo systemctl stop myapp
sudo systemctl disable myapp

2️⃣ Delete the service file:

sudo rm /etc/systemd/system/myapp.service

3️⃣ Reload systemd:

sudo systemctl daemon-reload

4️⃣ (Optional) Remove script:

sudo rm -r /opt/myapp

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🚀 Alternative Methods to Run Applications Without Creating a Service

1️⃣ Running in the Foreground (Basic Execution)

node /home/ubuntu/app.js

❌ Stops when the terminal is closed.

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2️⃣ Using nohup (Ignore Hangups)

nohup node /home/ubuntu/app.js > output.log 2>&1 &

✅ Keeps running after logout. ❌ No auto-restart if crashed.

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3️⃣ Using screen (Persistent Sessions)

screen -S myapp
node /home/ubuntu/app.js

🔹 Press Ctrl + A, then D to detach. 🔹 Reattach with:

screen -r myapp

❌ Stops on reboot.

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4️⃣ Using tmux (Better Alternative to Screen)

tmux new -s myapp
node /home/ubuntu/app.js

🔹 Detach with Ctrl + B, then D. 🔹 Reattach with:

tmux attach -t myapp

❌ Doesn’t persist after reboot.

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5️⃣ Using supervisor (Process Monitoring & Auto-Restart)

🔹 Install supervisor:

sudo apt update && sudo apt install supervisor -y

🔹 Create a configuration file:

sudo nano /etc/supervisor/conf.d/myapp.conf

🔹 Add the following content:

[program:myapp]
command=/usr/bin/node /home/ubuntu/app.js
autostart=true
autorestart=true
stderr_logfile=/var/log/myapp.err.log
stdout_logfile=/var/log/myapp.out.log

🔹 Apply changes and start the process:

sudo supervisorctl reread
sudo supervisorctl update
sudo supervisorctl start myapp

✅ Auto-restarts if the process crashes!

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🆚 Comparison: systemd vs. Other Methods

Method	Pros	Cons
🏆 systemd service	Best for production, auto-start, logging	Requires root access
🛠 nohup & &	Simple, keeps running	No auto-restart, hard to track
🔄 screen/tmux	Keeps running in a session	Stops after reboot
📊 Supervisor	Auto-restart, logging	Extra installation required

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🎯 Final Thoughts

✅ If you need a long-running, auto-managed process, use systemd services. ✅ If you need something temporary, nohup or screen/tmux are fine. ✅ If you need process monitoring, supervisor is a great option.

For DevOps & production environments, systemd services are the best choice! 🚀🔥

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💡 **Let me know if you need further clarifications!**😊