As written in the previous post, the VM upgrade (after a vSphere upgrade) require first the upgrade of the VMware Tools and then (if needed) the upgrade of virtual hardware. But there are also more considerations to do.
Some days ago, I was involved in a upgrade path a little unusual: from VI 3.5 (and also quite old, only U2) to vSphere 5. For hosts and vCenter Server was simple: just a re-installation and re-configuration. But there where more issues in the VMs upgrade.
Here some of my considerations:
- Seems obvious, but a VM check before start the upgrade could be really important: see if some service does not start, that there is enough space free in the system disk, …
- Both VMware Tools and virtual hardware upgrade can be orchestrated by VUM, but I suggest to use a manual upgrade for the first VMs (better with different type of VMs and guest OS).
- From the GUI the virtual hardware upgrade is only to version 8, so for an upgrade from VI 3.x it means go from v4 (that can be played without issue also on vSphere 5) directly to v8.
- The virtual hardware from v4 cause a virtual PCI slots reorder (this because from v7 they support the hot-add)… so, if you have more storage controller and/or more vNIC you can find them in a different order (this could be a problem with dual homed VMs).
- New VMware Tools are compatible with vSphere 4.x, but with VI 3.x? Seems yes, but I’ve found a random issue (on some VMs) where the flexible vNIC was not working… the fastest solution was change it with a new vNIC.
- For a big upgrade (from VI 3.x) I suggest to use (if possible) an interactive upgrade of the VMware Tools.
- The KB1012259 (VMware KB: msvcp71.dll is removed after uninstalling ESX/ESXi 3.5) is also valid for vSphere 5! Check if you have the file, save it before the upgrade and restore it. For example I’ve found that the issue on with VMs with SQL 2000, but not with SQL 2005 and later.
- For Linux VMs I use a different order: first the virtual hardware (that require a shutdown) and then (when the VM is powered-on) the VMware Tools (this operation, on Linux, does not require any reboot).
- For View, see the previous post.
- Remember to check and test the VMs also after the upgrade!