BASH
Check and Restart Web Service if Down
Create a robust Bash script to periodically check the status of a web service (e.g., Nginx, Apache) and automatically restart it if it's not running.
#!/bin/bash
SERVICE_NAME="nginx"
LOG_FILE="/var/log/service_monitor.log"
# Function to log messages
log_message() {
echo "$(date +'%Y-%m-%d %H:%M:%S') - $1" | tee -a "$LOG_FILE"
}
log_message "Checking status of $SERVICE_NAME..."
if systemctl is-active --quiet "$SERVICE_NAME"; then
log_message "$SERVICE_NAME is running."
else
log_message "$SERVICE_NAME is not running. Attempting to restart..."
systemctl start "$SERVICE_NAME"
if [ $? -eq 0 ]; then
log_message "$SERVICE_NAME restarted successfully."
else
log_message "Failed to restart $SERVICE_NAME."
# Optionally, send an alert here
# echo "Alert: $SERVICE_NAME failed to restart!" | mail -s "Service Alert" [email protected]
exit 1
fi
fi
How it works: This script monitors a specified system service (e.g., `nginx`). It uses `systemctl is-active --quiet` to check if the service is currently running. If the service is found to be inactive, the script attempts to start it and logs the outcome. This is an essential script for cron jobs to ensure critical web services remain online and can be extended with alerting functionality for immediate notifications.