Technical Support Request: EC2 Instance Frequent Unresponsiveness and SSH Failure [Instance ID: i-010bfad39caa5093f]

I understand the frustration with your EC2 instance becoming unresponsive despite showing "2/2 checks passed" in the AWS Management Console. This discrepancy between reported status and actual functionality is concerning, especially since it's a recurring issue.

Based on your description, here are some potential causes and troubleshooting steps:

1. Resource Exhaustion: Even though the instance appears healthy from AWS's perspective, it might be experiencing internal resource constraints:

• Check for memory exhaustion or high CPU utilization
• Look for disk space issues or I/O bottlenecks
• Review system logs (dmesg, /var/log/messages, /var/log/syslog) for errors

2. System Logs Analysis: When you regain access after a reboot:

• Check EC2 system logs through the AWS Management Console (Actions > Monitor and troubleshoot > Get System Log)
• Look for any error messages or unusual activity before the freeze

3. Instance Type Considerations:

• Evaluate if your current instance type provides sufficient resources for your workload
• Consider upgrading to a larger instance size if resource constraints are identified

4. Stop and Start vs. Reboot:

• Instead of just rebooting, try stopping and starting the instance (not just reboot)
• This migrates your instance to new hardware and can resolve underlying host issues

5. EC2 Serial Console:

• If SSH is unresponsive, try accessing your instance through the EC2 Serial Console
• This can provide direct console access when network connectivity fails

6. Automated Recovery Options:

• Set up CloudWatch alarms to monitor instance health
• Configure automatic recovery actions based on status checks or custom metrics

7. Network Configuration:

• Verify security group settings allow proper inbound/outbound traffic
• Check Network ACLs associated with your subnet

For a more permanent solution, consider creating an AMI of your instance and launching a replacement instance. This would rule out any hardware-level issues with the current instance.

If these steps don't resolve the issue, it might indicate a deeper problem with the underlying AWS infrastructure, in which case further investigation by AWS support would be necessary.
Sources
EC2 instance randomly fails 1/2 status checks at 4:30 AM with no user activity — SSH and APIs become unresponsive | AWS re:Post
EC2 Instance Freeze | AWS re:Post
Assistance Required for Non-Responsive EC2 Instance | AWS re:Post
Error establishing SSH connection to your instance. Access to EC2 has been lost | AWS re:Post