Troubleshooting Compute Engine Instance Failure

Troubleshooting Compute Engine Instance Failure

Question

Your application is running on Compute Engine and is showing sustained failures for a small number of requests.

You have narrowed the cause down to a single Compute Engine instance, but the instance is unresponsive to SSH.

What should you do next?

Answers

Explanations

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A. B. C. D.

A.

If the Compute Engine instance is unresponsive to SSH, it might be challenging to diagnose the cause of the failures. However, the following options are available to recover the instance:

A. Reboot the machine: A reboot might help resolve the issue if it is related to a temporary error, such as an unresponsive process or a stuck I/O operation. However, if the issue is related to the instance's configuration, the reboot might not solve the problem.

B. Enable and check the serial port output: The serial port output provides a low-level view of the instance's boot process, including kernel messages, init scripts, and startup logs. By enabling the serial port output, you can view the logs and diagnose the cause of the instance's unresponsiveness. To enable serial port output for an instance, you can follow the steps described in the Compute Engine documentation.

C. Delete the machine and create a new one: If the issue is not recoverable, you can delete the unresponsive instance and create a new one with the same configuration. However, this option might cause data loss if the instance's disk is not backed up.

D. Take a snapshot of the disk and attach it to a new machine: If the data on the instance's disk is valuable, you can take a snapshot of the disk and create a new instance with the same configuration, using the snapshot as the disk. This option ensures that the data on the instance's disk is preserved and can be recovered if necessary.

Overall, the best option depends on the cause of the instance's unresponsiveness and the importance of the data on the instance's disk. Enabling the serial port output is the first step to diagnose the issue, and depending on the severity of the issue, you might choose to reboot the machine, delete the machine and create a new one, or take a snapshot of the disk and attach it to a new machine.