Powering on virtual machines on available ESX hosts after ESX host failure without HA configured

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

This article explains methods to restart virtual machines on available ESX hosts after an ESX host has encountered a fault crash or when VMware High Availability (HA) is not enabled on the cluster.

Note: HA reduces downtime and powers up virtual machines on the other available hosts automatically depending on configuration and settings.

Symptoms:
connect-esx cannot-view-esx-health-status vcenter-configure-ha esx-fault-crash-recovery

Environment

VMware vSphere ESXi 5.0
VMware ESX 4.1.x
VMware vSphere ESXi 5.1
VMware vCenter Server 4.1.x
VMware vCenter Server 4.0.x
VMware vSphere ESXi 5.5
VMware vCenter Server 5.0.x
VMware vCenter Server 5.5.x
VMware vCenter Server 5.1.x
VMware ESX 4.0.x

Resolution

After ESX failure, if the host is not brought back into the cluster through troubleshooting and if HA is not configured, you have to manually power up the virtual machines on other available ESX hosts.

Note: This article assumes that the virtual machines are stored on shared storage that is accessible to all the other ESX hosts in the cluster. Virtual machines that are on local storage or are not on shared storage cannot be powered up on the other servers.

To power up the virtual machines manually on the other available ESX hosts, you need this information about the virtual machines:

• The name of the virtual machines
• The location of the .vmx file of these virtual machines

To power up the virtual machines manually on the available servers:

1. Log in to the vCenter Server using the vSphere Client.
2. If the ESX host that has failed shows up as grayed out in the vCenter Server inventory, right-click on that host and choose Remove from Inventory.
   
   Note: This step is required as vCenter Server does not multiple registrations of virtual machines. By removing the ESX host from the inventory, vCenter Server is now unaware of the virtual machines that are registered on the host that is down. This allows you to re-register the virtual machines on the other ESX hosts in the vCenter Server inventory.
   
   
3. From vSphere Client, browse to the datastores and find the files associated with the virtual machine that you want to register and power on.
4. Right-click the .vmx file of the virtual machine and choose Add to Inventory.
5. Follow the steps in the wizard to completion.
6. When the virtual machine is registered, power on the virtual machine.
7. Repeat steps 4 -7 for all virtual machines that you want to register and power up.

To bring the failed ESX host back into the cluster:

1. Connect to the ESX host directly using the vSphere Client (log in with root credentials).
2. You see the virtual machines that were registered to this host. They should all be in a powered off state.
3. Right-click on the virtual machines showing registered on this ESX host and choose Remove from Inventory.
4. From the vCenter Server, add this host back into the cluster by right-clicking on the cluster and selecting Add Host.
5. Follow the steps in the wizard to completion.
6. You can now load balance the virtual machines using DRS or by manually migrating virtual machines.

Additional Information

For more information on setting up (HA), see:

• The vSphere Availability Guide for your version of vSphere.

• Automating High Availability (HA) Services with VMware HA