Amazon EC2


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).
  • 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.

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.
  • Verify that the instance has public IP.
  • Check route table and ensure it routes traffic correctly.
  • Inspect the security group settings.

Correct routing and security group rules.
Issue #3: Instance Not Responding
The instance becomes unresponsive and doesn't react to input or network requests.
  • 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.

  • 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.
  • Investigate security groups.
  • AWS CloudTrail and VPC Flow Logs helps in detecting suspicious activities.

  • 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.
  • Identify large files or directories consuming disk space.
  • Use the df (Linux) or Disk Management (Windows) to check disk usage.

  • Delete unneeded files,
  • Resize the EBS volume,
  • Consider implementing automatic scaling for storage.