🚀Day 12 – Systemd and Linux Services

Welcome to Day 11 of my 100 Days of DevOps journey!
Today, I explored how to manage services in Linux using systemd. This is a crucial skill for maintaining and deploying applications in production environments.

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🧠 What is systemd?

systemd is the modern init system for most Linux distributions. It handles:

• Boot process

• Background services (daemons)

• Logging with journald

• Resource control and service dependencies

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🔧 Common Commands

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🛠️ Real Example: Custom Background App with systemd

✅ Step 1: Create a Simple Script

mkdir -p ~/myapp
nano ~/myapp/app.sh

Paste:

#!/bin/bash
while true; do
  echo "$(date) - My custom app is running..." >> /home/ritesh/myapp/app.log
  sleep 10
done

Make it executable:

chmod +x ~/myapp/app.sh

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✅ Step 2: Create a Systemd Unit File

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

Paste:

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

[Service]
ExecStart=/home/ritesh/myapp/app.sh
Restart=always
User=ritesh

[Install]
WantedBy=multi-user.target

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✅ Step 3: Start and Enable the Service

sudo systemctl daemon-reload
sudo systemctl start myapp.service
sudo systemctl enable myapp.service

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🔍 Step 4: Check Logs and Status

systemctl status myapp.service
journalctl -u myapp.service -f
tail -f ~/myapp/app.log

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❌ Step 5: Stop and Clean Up

sudo systemctl stop myapp.service
sudo systemctl disable myapp.service
sudo rm /etc/systemd/system/myapp.service
sudo systemctl daemon-reload

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📌 Summary

✅ Learned systemd and unit file structure
✅ Created a persistent, restartable custom service
✅ Managed logs and service status with journalctl and systemctl
✅ Prepared for production-level Linux service management

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📚 References:

• Systemd Cheat Sheet

• Understanding systemd Units

• Journalctl Guide

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🔗 GitHub Repo: DevOps Journal
✍️ Hashnode Blog: Day 12– Systemd and Linux Services