Amazon EC2
EC2 COMMON ISSUES
By Abhinay Durishetty
6 mins read
Common EC2 Issues and Troubleshooting Techniques
Issue #1: Instance Not Accessible
Unable to connect to the instance via SSH (Linux) or RDP (Windows).
Troubleshooting:
Fix:
Correct security group rules, check key pairs, and validate public IP.
- Ensure the instance is running and in a "running" state.
- Verify the security group and allow inbound traffic on the respective ports (22 for SSH, 3389 for RDP).
- Confirm that public IP is associated with the instance.
- Ensure the private key or password used for authentication is accurate.
Fix:
Correct security group rules, check key pairs, and validate public IP.
Issue #2: Instance Network Connectivity Issues
The instance cannot access the internet or other AWS resources.
Troubleshooting:
Fix:
Correct routing and security group rules.
- Verify that the instance has public IP.
- Check route table and ensure it routes traffic correctly.
- Inspect the security group settings.
Fix:
Correct routing and security group rules.
Issue #3: Instance Not Responding
The instance becomes unresponsive and doesn't react to input or network requests.
Troubleshooting:
Fix:
- Check CPU, memory, and disk usage during unresponsiveness.
- Identify processes or applications consuming excessive resources using tools like top (Linux) or Task Manager (Windows).
- Review system logs and application logs for error messages.
Fix:
- Consider resizing the instance to a higher CPU or memory type.
- Force a reboot or stop/start the instance to recover.
- Optimise the application code.
Issue #4: Security Breach or Unauthorized Access
Suspected security breach or unauthorized access to the instance.
Troubleshooting:
Fix:
- Investigate security groups.
- AWS CloudTrail and VPC Flow Logs helps in detecting suspicious activities.
Fix:
- Rotate access keys and credentials if compromised.
- Secure the instance, apply security patches.
- Follow AWS best practices for security.
Issue #5: Instance Running Out of Disk Space
The instance is running low on disk space, affecting performance and functionality.
Troubleshooting:
Fix:
- Identify large files or directories consuming disk space.
- Use the df (Linux) or Disk Management (Windows) to check disk usage.
Fix:
- Delete unneeded files,
- Resize the EBS volume,
- Consider implementing automatic scaling for storage.