🚀 Day 14: Effective Log Management and Rotation Strategies

Welcome to Day 14 of my 100 Days of DevOps journey!
Today I explored log management and log rotation — an essential DevOps skill for system stability, debugging, auditing, and monitoring.

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📂 What Are Logs in Linux?

Logs are system-generated messages that record everything from boot information, user actions, process statuses, and service errors.

🗂️ Common Linux log files:

👀 View logs using:

sudo tail -f /var/log/syslog
sudo journalctl -u ssh.service
grep "error" /var/log/auth.log

🔁 Why Log Rotation Matters

Without rotation, log files can grow indefinitely and consume disk space.
Log rotation helps by:

• Archiving old logs

• Compressing them to save space

• Automatically deleting older ones

• Keeping systems clean and readable

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🔧 Tool: logrotate

Most Linux systems use logrotate to automate log rotation.

📌 Default config:

• Global: /etc/logrotate.conf

• Per-app: /etc/logrotate.d/

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📐 My Custom Log Rotation Setup

✅ 1. Simulate a Log File

mkdir -p ~/logs
echo "Log started at $(date)" > ~/logs/myapp.log

Then simulate appending:

nohup bash -c 'while true; do echo "$(date): app log entry" >> ~/logs/myapp.log; sleep 2; done' &

📝 2. Create Logrotate Config

Create a file:

sudo nano /etc/logrotate.d/myapp

Paste:

Paste:

/home/ritesh/logs/myapp.log {
    daily
    rotate 5
    compress
    missingok
    notifempty
    create 644 ritesh ritesh
    su ritesh ritesh
}

📌 Explanation:

• daily: rotate once per day

• rotate 5: keep 5 old logs

• compress: gzip old logs

• create: re-create log after rotation

• su: run rotation as my user

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🧪 3. Test It

📌 Dry run:

sudo logrotate -d /etc/logrotate.d/myapp

📌 Force rotation:

sudo logrotate -f /etc/logrotate.d/myapp

📁 Result:

ls -lh ~/logs/
# myapp.log         -> current log file
# myapp.log.1.gz    -> rotated & compressed

🧠 Extras

🧹 Clean old systemd journal logs:

sudo journalctl --vacuum-time=2weeks

🧰 Useful tools:

• GoAccess – web log analyzer

• ELK Stack – advanced log management

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📌 Key Learnings

✅ Understood core Linux logs and their importance
✅ Learned how to manage logs using logrotate
✅ Created a real-time rotating app log
✅ Prepared for production-grade log hygiene

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📚 References:

• Journalctl Cheatsheet

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🔗 Hashnode Blog: Day 14 – Log Management and Rotation
📘 GitHub Repo: DevOps Journal