Send Diagnostic Interrupts

What is a Diagnostic Interrupt?

A diagnostic interrupt is a low-level signal sent to an Amazon EC2 instance to trigger system debugging or troubleshooting actions.

When to Use Diagnostic Interrupts

• Instance is unresponsive and cannot be rebooted.
• Need to capture system logs before forcefully stopping an instance.
• Investigate kernel panics, frozen processes, or hardware-related failures.

IAM Permissions Required

Ensure that your AWS IAM user or role has the following permissions:

{
    "Effect": "Allow",
    "Action": "ec2:SendDiagnosticInterrupt",
    "Resource": "arn:aws:ec2:region:account-id:instance/instance-id"
}

How to Send a Diagnostic Interrupt

Using the AWS CLI, you can send a diagnostic interrupt to an EC2 instance:

aws ec2 send-diagnostic-interrupt --instance-id i-1234567890abcdef0

Or, use the AWS Console:

1. Go to the **EC2 Dashboard**.
2. Select the instance.
3. Click **Actions** → **Manage Instance State** → **Send Diagnostic Interrupt**.
4. Confirm the action.

Verify the Diagnostic Interrupt

After sending the interrupt, check system logs using:

dmesg | tail

Or use the serial console for debugging:

cat /var/log/messages | grep diagnostic

Limitations and Considerations

• Diagnostic interrupts may not work if the instance is completely frozen.
• Not all instance types support this feature.
• May require the EC2 Serial Console to review logs effectively.