ESXi 5.1 Manual/Force Upgrade
One of the great features of vCenter 5.1 is the ability to upgrade older 4.x ESX/ESXi hosts to 5.1 from within Upgrade Manager. This being said, I have had several recent deployments where this has not being an option due to perceived incompatibilities between installation media (both branded & unbranded) and the host. The other issue I have found is that the Update Manager method doesn’t automatically recognize the ESX/ESXi partition. Even after installing the latest host firmware(which I would highly recommended) and confirming it is on the compatibility list of supported hardware for ESXi 5.1 I still receive “The upgrade is not supported on the host hardware. The upgrade ISO image contains HP (or other vendor) VIBs that failed the host hardware vendor compatibility check. VIBs by HP are not supported on host hardware model Hewlett-Packard Company made by vendor.”
It is possible to customize your install image and add/remove VIBs as required but I have found the easiest way to resolve this is by doing a manual upgrade. This can be done be done directly from the host, or my preferred method – Out-of-Band Management, Dell DRAC, HP iLO, IBM AMM, etc.
Mount your VMware ESXi 5.1 media (or insert CD) and restart host.
You will see the ESXI 5.1 Splash Screen which will continue to load the various modules
After all the modules load (Approx. 5-10min) you will be presented with the following install screen. Hit enter on your keyboard to continue past this screen & F11 to accept the EULA on the following.
The installer then scans through available hardware and you are faced Disk selection option. Select your ESX/ESXi install volume and press Enter to continue.
You are then faced with upgrade/install options. IMPORTANT: Do NOT select overwrite VMFS datastore unless you are prepared to lose all of your Virtual Machines or really enjoy restoring all of your data from backups… Select Force Migrate ESX, preserve VMFS datastore and Enter to continue. On the following screen you are asked to confirm. Hit F11 if you are happy to proceed
Depending on your hardware, after approximately 10-15min you should see a message indicating “Force Migrate Complete.” Select enter to reboot.
After couple of reboots you should find yourself at the VMware ESXi 5.1 splash screen and be able to access your host via vCenter 5.1.