K3s Resource Cleanup

This script installs and configures an automated K3s cleanup system that helps maintain your K3s cluster by removing stopped containers and unused images.

📋 What it does

The installation script sets up:

A cleanup script at /usr/local/bin/k3s-cleanup.sh
A configurable cron job (default: daily at 2:00 AM)
Logging to /var/log/k3s-cleanup.log
Logrotate configuration to manage log retention (default: 7 days)
Uses full path /usr/local/bin/k3s for cron compatibility

The cleanup process:

✅ Removes stopped containers (Created/Exited state)
✅ Removes unused images to free up disk space
✅ Shows disk usage before and after cleanup
✅ Logs all operations with timestamps

🚀 Quick Installation

Direct execution with defaults (2:00 AM daily, 7 days log retention)

curl -fsSL https://eliasmeireles.com.br/tools/k8s/install-k3s-cleanup.sh | sudo bash

Direct execution with custom options

# Download and run with custom schedule (e.g., every 6 hours)
curl -fsSL https://eliasmeireles.com.br/tools/k8s/install-k3s-cleanup.sh | sudo bash -s -- -s '0 */6 * * *'

# With custom log retention (16 days)
curl -fsSL https://eliasmeireles.com.br/tools/k8s/install-k3s-cleanup.sh | sudo bash -s -- -lk 16

# With custom schedule and log retention
curl -fsSL https://eliasmeireles.com.br/tools/k8s/install-k3s-cleanup.sh | sudo bash -s -- -s '0 */6 * * *' -lk 16

Manual installation

# Download the script
wget https://eliasmeireles.com.br/tools/k8s/install-k3s-cleanup.sh

# Make it executable
chmod +x install-k3s-cleanup.sh

# Run with defaults (2:00 AM daily, 7 days retention)
sudo ./install-k3s-cleanup.sh

# With custom schedule
sudo ./install-k3s-cleanup.sh -s '0 */6 * * *'

# With custom log retention
sudo ./install-k3s-cleanup.sh -lk 16

# With custom schedule and log retention
sudo ./install-k3s-cleanup.sh -s '0 */6 * * *' -lk 16

# Show help
sudo ./install-k3s-cleanup.sh -h

📋 Requirements

Root privileges: The script must be run as root or with sudo
K3s installed: The script requires K3s to be installed at /usr/local/bin/k3s
cron service: For automated scheduling (usually pre-installed on most systems)

🛠️ Command-Line Options

Flag	Long Form	Description	Default
`-s`	`--schedule`	Cron schedule expression	`0 2 * * *` (2:00 AM daily)
`-lk`	`--log-keep`	Days to keep logs	`7`
`-h`	`--help`	Show help message	-

🔧 Usage

After Installation

The script automatically sets up a daily cron job, but you can also run it manually:

# Run cleanup manually
sudo /usr/local/bin/k3s-cleanup.sh

# View cleanup logs
sudo tail -f /var/log/k3s-cleanup.log

# Check current cron jobs
crontab -l | grep k3s-cleanup

Manual Cleanup Operations

If you need more control, you can use K3s crictl commands directly:

# List all containers
sudo k3s crictl ps -a

# Remove specific stopped containers
sudo k3s crictl rm <container-id>

# List all images
sudo k3s crictl images

# Remove unused images
sudo k3s crictl rmi --prune

📊 Monitoring

Check Disk Usage

# Before cleanup
df -h | grep mnt

# View cleanup history
sudo grep "Disk usage" /var/log/k3s-cleanup.log

View Logs

# View recent cleanup logs
sudo tail -20 /var/log/k3s-cleanup.log

# View all cleanup logs
sudo cat /var/log/k3s-cleanup.log

# Follow logs in real-time
sudo tail -f /var/log/k3s-cleanup.log

# View rotated logs (compressed)
sudo zcat /var/log/k3s-cleanup.log.1.gz

# Check logrotate configuration
cat /etc/logrotate.d/k3s-cleanup

⚙️ Configuration

Modify Cron Schedule and Log Retention

You can change the schedule and log retention by running the installation script again:

# Change schedule only
sudo ./install-k3s-cleanup.sh -s '0 */6 * * *'

# Change log retention only
sudo ./install-k3s-cleanup.sh -lk 30

# Change both schedule and log retention
sudo ./install-k3s-cleanup.sh -s '0 */6 * * *' -lk 16

# The script will:
# 1. Remove the existing crontab entry
# 2. Create a new entry with the updated schedule
# 3. Update logrotate configuration

Schedule Examples

sudo ./install-k3s-cleanup.sh -s '0 2 * * *'      # Daily at 2:00 AM (default)
sudo ./install-k3s-cleanup.sh -s '0 */6 * * *'    # Every 6 hours
sudo ./install-k3s-cleanup.sh -s '30 3 * * *'     # Daily at 3:30 AM
sudo ./install-k3s-cleanup.sh -s '0 1 * * 0'      # Weekly on Sunday at 1:00 AM
sudo ./install-k3s-cleanup.sh -s '0 3 1 * *'      # Monthly on 1st day at 3:00 AM

Log Retention Examples

sudo ./install-k3s-cleanup.sh -lk 7     # Keep logs for 7 days (default)
sudo ./install-k3s-cleanup.sh -lk 16    # Keep logs for 16 days
sudo ./install-k3s-cleanup.sh -lk 30    # Keep logs for 30 days

Manual Crontab Edit

Alternatively, you can edit the crontab directly:

# Edit crontab
sudo crontab -e

# Modify the schedule in the k3s-cleanup entry

Disable Automatic Cleanup

# Remove from crontab
sudo crontab -e
# Delete the line containing k3s-cleanup.sh

🔍 Troubleshooting

Common Issues

Script fails with “k3s command not found”

# Check if k3s is installed at the expected location
ls -la /usr/local/bin/k3s

# If k3s is elsewhere, create a symlink
sudo ln -s $(which k3s) /usr/local/bin/k3s

# The script uses full path /usr/local/bin/k3s for cron compatibility

Permission denied errors

# Ensure script has correct permissions
sudo chmod +x /usr/local/bin/k3s-cleanup.sh

# Check file ownership
ls -la /usr/local/bin/k3s-cleanup.sh

Cron job not running

# Check if cron service is running
sudo systemctl status cron

# Start cron service if needed
sudo systemctl start cron
sudo systemctl enable cron

Logs not rotating

# Check logrotate configuration
cat /etc/logrotate.d/k3s-cleanup

# Test logrotate manually
sudo logrotate -d /etc/logrotate.d/k3s-cleanup

# Force logrotate
sudo logrotate -f /etc/logrotate.d/k3s-cleanup

Verification

# Test the cleanup script manually
sudo /usr/local/bin/k3s-cleanup.sh

# Check if cron job is scheduled
sudo crontab -l | grep k3s-cleanup

# Verify log file exists and is writable
ls -la /var/log/k3s-cleanup.log

🗑️ Uninstallation

To remove the cleanup system:

# Remove the script
sudo rm /usr/local/bin/k3s-cleanup.sh

# Remove from crontab
sudo crontab -e
# Delete lines containing k3s-cleanup

# Remove logrotate configuration
sudo rm /etc/logrotate.d/k3s-cleanup

# Remove log files (optional)
sudo rm /var/log/k3s-cleanup.log*

📝 Notes

The script is designed to be safe and will only remove stopped containers and unused images
All operations are logged with timestamps for audit purposes
The script includes error handling and will exit safely if K3s is not available
Disk usage is shown before and after cleanup to track space savings
Uses full path /usr/local/bin/k3s to ensure cron jobs work correctly
Re-running the installation script will replace the existing crontab entry with the new configuration
Logrotate automatically manages log files, compressing old logs and removing them after the retention period
All options support both short (-s, -lk) and long (--schedule, --log-keep) forms
Use -h or --help to see all available options