Log Rotation and Cleanup Scripts

🛠️ Why Log Rotation and Cleanup Matters

In real-world observability:

✅ Logs grow very fast:

• Application logs
• Monitoring logs
• System audit logs

✅ If you don't rotate or clean up:

• The disk gets full
• Servers crash
• Incidents become harder to debug

✅ Managing logs = Managing system health and reliability.

🛠️ What is Log Rotation?

✅ Log rotation means:

• Archiving old logs
• Compressing them to save space
• Starting new fresh logs
• Deleting very old logs after a few days

✅ Keeps your system healthy and searchable without eating up all disk space.

📚 Example 1: Manual Log Rotation Script (Simple)

#!/bin/bash

log_file="/var/log/myapp.log"
timestamp=$(date +%Y%m%d_%H%M%S)
archive_dir="/var/log/archive"

mkdir -p $archive_dir

cp $log_file $archive_dir/myapp.log.$timestamp
> $log_file  # Empty the original log file

echo "Log rotated and archived as myapp.log.$timestamp"

        

✅ What happens:

• Copy current log with timestamp
• Empty original log file
• Store archive safely

📚 Example 2: Auto Compress Old Logs

#!/bin/bash

find /var/log/archive -name "*.log*" -mtime +7 -exec gzip {} \\;

        

✅ Meaning:

• Find log files older than 7 days
• Compress them into .gz

✅ Compression saves disk space heavily in observability setups!

📚 Example 3: Cleanup Very Old Logs

#!/bin/bash

find /var/log/archive -name "*.gz" -mtime +30 -exec rm {} \\;

        

✅ Meaning:

• Find compressed logs older than 30 days
• Delete them safely

✅ Always keep a balance between retention and disk usage.

🛠️ How to Automate Log Rotation with Cron

✅ Add this to crontab:

0 2 * * * /home/ubuntu/scripts/rotate_logs.sh > /tmp/rotate_logs.log 2>&1

        

✅ Rotate logs every night at 2 AM

✅ Log rotation itself logs to /tmp/rotate_logs.log

✅ Self-healing observability — no human intervention needed.

🛠️ Bonus: Linux logrotate Tool

✅ Linux has a built-in tool called logrotate!

✅ For complex setups, you can configure /etc/logrotate.d/yourapp:

/var/log/myapp.log {
    daily
    rotate 7
    compress
    missingok
    notifempty
    create 0640 ubuntu ubuntu
}

        

• Rotate daily
• Keep 7 copies
• Compress old logs
• Skip missing or empty logs
• Create new log files properly

✅ logrotate runs automatically via cron!

✅ But small shell scripts are super useful for custom automation.

🧠 Simple Analogy

Log rotation is like taking out the trash 🗑️:

• You don't keep every pizza box forever 🍕
• You archive important stuff
• You compress when needed
• You clean out very old junk

✅ Good observability = Good log hygiene.

Preventive log management saves production systems!

🗺️ Where Are We in the Journey?

Linux Fundamentals → Kubernetes Observability → Shell Basics → Background Jobs → Scheduling with Cron → (Now) Smart Log Rotation & Cleanup

        

You are now automating true system hygiene for observability!