Losing ssh connection into my Lightsail and EC2 AWS after a while

Common Causes: Network Configuration Changes: Firewall rules or security groups may have changed. Resource Exhaustion: High CPU or memory usage might affect SSH service responsiveness. SSH Service Issues: The SSH service (sshd) might have stopped or crashed. IP Changes: The public IP of the instance might have changed (especially for EC2 without Elastic IP). Security Group Rules: Security group rules might inadvertently block SSH traffic. Diagnostic Steps: Check Security Group and Firewall Rules:

Ensure security group allows SSH traffic on port 22. Verify instance firewall rules (iptables or firewalld) to ensure SSH is not blocked. Check Resource Usage:

Use instance's console to check CPU and memory usage with commands like top or htop. Restart SSH Service:

Use the instance’s console to restart SSH service: sudo systemctl restart sshd or

sudo service sshd restart Check the status of the SSH service: sudo systemctl status sshd or sudo service sshd status Check SSHD Logs:

Review SSHD logs for errors or warnings: sudo tail -f /var/log/auth.log or sudo tail -f /var/log/secure Verify IP Address:

Confirm the instance’s public IP has not changed. For EC2, consider using an Elastic IP. Re-establish SSH Connection:

Try reconnecting: ssh -i /path/to/key.pem username@your_instance_ip Preventive Measures: Use Elastic IPs: For EC2, to ensure the public IP does not change. Monitor Resources: Implement monitoring for CPU, memory, and network usage to get alerts if the server is under heavy load. Keep Security Groups Updated: Regularly review and update security group rules. Automated Service Monitoring: Set up automated monitoring and recovery for SSHD using tools like monit. Following these steps will help you diagnose the issue with your SSH connection and take preventive measures to avoid it in the future.

Hi,

Please check if your Lightsail instance status check is failing. You can view these metrics on the Lightsail console as per instructions here

If your instance had high CPU Utilization (or was in the burstable zone) for a long period of time, it can impair the performance of the instance or result in exhausted memory and lead to above. Doing a stop/start on your Lightsail instance may help fix the issue.

Applications and processes you are trying to run on the server maybe unsuitable for your chosen Lightsail instance plan or bundle size. Please consider upgrading you server size if you need all of them or diagnose and disable any faulty scripts, unwanted applications, etc.

To upgrade your Lightsail instance plan please create an instance snapshot and then create a larger instance from the snapshot

Thanks.