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Lab 11.4 - Monitoring Crons and Alerts

Objectives​

  • Monitor cron execution
  • Detect failures
  • Configure alerts
  • Create reports

Exercise 1: View Cron Logs​

# Cron logs
sudo journalctl -u cron

# Filter by script
sudo journalctl -u cron | grep my-script.sh

Exercise 2: Monitoring Script​

# Check execution
cat > check-cron.sh << 'EOF'
#!/bin/bash
SCRIPT="my-script.sh"
TODAY=$(date +%b\ %d)
EXECUTED=$(sudo journalctl -u cron | grep "$SCRIPT" | grep "$TODAY" | wc -l)

if [ "$EXECUTED" -eq 0 ]; then
    echo "ALERT: $SCRIPT has not been executed today"
fi
EOF

chmod +x check-cron.sh

Exercise 3: Email Alerts​

# Configure email in crontab
crontab -e
# Add: MAILTO=your-email@example.com

# Script with notification
cat > script-with-alert.sh << 'EOF'
#!/bin/bash
if ! my-script.sh; then
    echo "Failure" | mail -s "Cron Alert" admin@example.com
fi
EOF

Lab created on: December 2024 - Tested on Ubuntu 24.04