aws m4.xlarge unreachable in aws controls, changing type to m5 solves the situation

Hello,

Thank you for reaching out on this use case. Although, the details of the error seen or why the instance was not reachable is not clear on the query but here are common causes of the issue.

Findings

M4.xlarge Instance type generally uses Intel 82599 VF interface for networking and PV drivers for storage while M5.xx Instance types uses ENA for networking and NVMe for storage performance. - See Network performance and Instance features respectively.

Usually driver corruption can occur on the OS hence, leading to this issues. AWS on default preinstall most of this drivers on the AMI which explains why changing it to M5 works.

M5 instances are Nitro Instances while M4.xlarge are PV/HVM instances. They have different drivers requirements

Resolution

To resolve this, kindly perform the following actions below:

• Back up the Instance by creating the point in time Snapshot or AMI of the Instance in scope.
• Install the latest drivers of the Intel 82599 VF interface and PV drivers
  • To update the PV drivers, see the documentation Install and upgrade AWS PV drivers
  • To update the ENA Intel VF, refer to the documentation Enable enhanced networking with the Intel 82599 VF interface on Windows instance Depending on the Instance OS version, update the EC2Launch or EC2Config on the instance. Update EC2Config and EC2Launch
• Then, stop the Instance and revert to M4.xlarge instance type.

If you encounter an issue, feel free to reach out to AWS Premium Support