Troubleshooting: Virtual Machine (VM) Startup Failure

Encountering a situation where a virtual machine (VM) fails to start up can be a concerning and challenging experience for any VMware ESXi administrator. In such instances, critical services may be disrupted, and the overall performance of your virtual infrastructure could be impacted.

This comprehensive guide is designed to provide a step-by-step troubleshooting process to help you diagnose and resolve issues when a VM will not start up. By following these systematic troubleshooting steps, you can identify potential causes of the problem and implement appropriate solutions to get your virtual machine up and running again.

Understanding the VM startup process, reviewing logs, checking configuration settings, and ensuring resource availability are essential components of this troubleshooting endeavor. By applying this guide, you will be equipped to effectively address VM startup issues, maintain a seamless virtual infrastructure, and ensure the uninterrupted operation of your virtual machines.

Step 1: Verify VM Configuration

Begin the troubleshooting process by verifying the virtual machine’s configuration settings:

1. Log in to the vSphere Client or vCenter Server.
2. Navigate to the “Hosts and Clusters” view.
3. Locate the VM that is not starting up and select it.
4. Click on the “Summary” tab and review the VM’s configuration settings, such as CPU, memory, and storage.
5. Ensure that the VM’s hardware configuration is compatible with the ESXi host and that the assigned resources are appropriate for the VM’s workload.

Step 2: Check VM Power State and Console

Next, check the VM’s power state and console to gather more information about its current state:

1. In the vSphere Client, navigate to the “Hosts and Clusters” view.
2. Locate the VM and check its power state (Powered On, Powered Off, or Suspended).
3. If the VM is Powered Off or Suspended, try powering it on and observe any error messages in the console.
4. If the VM fails to power on, note any error messages or indicators of potential issues.

Step 3: Review VM Events and Logs

Examine VM events and logs to identify any error messages or issues that occurred during the VM’s startup process:

1. Select the VM that is not starting up.
2. Click on the “Monitor” tab and select “Events” to review recent events related to the VM.
3. Check the ESXi host’s logs (vmkernel.log and hostd.log) for any error messages or events that occurred during the VM’s startup.
4. Review the VM’s logs (vmware.log) to gather more information about the startup process.

Step 4: Verify Storage Connectivity

Ensure that the VM’s virtual disks are accessible and that the storage is properly connected to the ESXi host:

1. Navigate to the “Hosts and Clusters” view.
2. Locate the VM that is not starting up and select it.
3. Click on the “Summary” tab and review the VM’s virtual disks and their associated datastores.
4. Check the datastore’s accessibility and connectivity to the ESXi host.
5. If using shared storage (SAN or NAS), ensure that the storage device is functioning correctly and accessible from the host.

Step 5: Check Resource Availability

Ensure that there are sufficient resources available on the ESXi host to start the VM:

1. In the vSphere Client, navigate to the “Hosts and Clusters” view.
2. Select the ESXi host that contains the VM that will not start up.
3. Click on the “Summary” tab and review the host’s resource utilization, including CPU, memory, and storage.
4. If the host’s resources are heavily utilized, consider migrating other VMs or adjusting resource allocations to free up resources for the troubled VM.

Step 6: Try a Cold Boot or Restart Management Agents

If the VM is unresponsive or stuck during the startup process, try a cold boot or restart the management agents:

1. In the vSphere Client, navigate to the “Hosts and Clusters” view.
2. Select the ESXi host that contains the VM.
3. Click on the “Summary” tab and select “Restart Management Agents” from the “Actions” menu.
4. If the issue persists, try performing a cold boot on the VM by powering it off completely and then powering it back on.

Step 7: Review Hardware and VM Configuration Changes

If the VM was recently modified or hardware changes were made, review and revert any recent changes that may have caused the startup issue:

1. In the vSphere Client, navigate to the “Hosts and Clusters” view.
2. Locate the VM that is not starting up and select it.
3. Click on the “Summary” tab and review the VM’s recent tasks and events to identify any configuration changes.
4. If hardware changes were made, such as adding new devices or removing existing ones, consider reverting those changes to see if it resolves the issue.

Conclusion:

Troubleshooting a VM that will not start up requires a systematic approach to identify and resolve potential issues. By following this comprehensive guide, you have successfully performed a step-by-step troubleshooting process to diagnose and address the problem. Whether it’s a configuration issue, storage problem, resource constraint, or recent change, understanding the VM startup process and analyzing logs are crucial in resolving the issue and ensuring the seamless operation of your virtual infrastructure.