After upgrading vCenter in a previous post, I used the Update Manager inside vCenter to upgrade in an easy and automated way several ESXi hosts to version 5.0.

First of all, we need to import ISO images of ESXi 5.0, previously downloaded. We open then the Admin View of Update Manager, we select the ESXi Images tab, and we import the ISO image:

In the last tab of the wizard, we are asked to create the new Host Upgrade baseline, and we accept it:

Now we can attach the new baseline to our cluster and start a scan. ESXi 4.1 nodes appear at the end as non compliant, and we can update them through the Remediate option. There is another kind of result you could have, “incompatible”. The reason can be some additional drivers installed in the ESXi 4.1, like this:

In this server we added a HP NC365T network card, unidentified by ESXi ans so we installed additional drivers, as described in previous post.

In my environment I have DRS in place, so I do not need to do anything on VMs and nodes. If you do not have it, migrate first VMs away from the node you’re going to upgrade using vMotion, or manually if you do not have even vMotion.

The upgrade itself is quick and easy, and after several minutes you will have the node upgraded to ESXi 5.0.