For anyone out there still using ESX(i) 3.5 you will need to apply a specific patch to your hosts to be able to continue updating these after June 2011. This patch updates a secure key which will allow future patches to be applied.
Follow the links below to the VMware KB articles for further information.
KB: 1030001 Critical Impact: VMware ESX 3.5, Patch ESX350-201012410-BG: Apply this patch to continue applying patches on ESX 3.5 hosts after June 2011 has been written for users of ESX.
KB: 1030002 Critical Impact: VMware ESXi 3.5, Patch ESXe350-201012401-I-BG: Apply this patch to continue applying patches on ESXi 3.5 hosts after June 2011 has been written for users of ESXi.
Will it still be possible to upgrade the hosts to 4.0 or 4.1 after June 1, if I don’t apply the patch now?
Yes that will still be possible using the host update utility or Update Manager
what happens if a reinstall of ESX is required from June onwards?
@Ian You need to re-apply the patch. Best idea is include it in your standard build
Are you able to apply the patch after the cut off date and then carry on patching, or did the patch need to be applied before the date?
@James You can apply the patch afterwards I believe. I am not able to test as I no longer have any ESX 3.5 hosts in my lab. If you find this isn’t the case, let me know and I will update the article accordingly.
You can install the patch after 1 June 2011 by using the –nosig switch with esxupdate OR you can set the date of the server prior to 1 June 2011 and install. The –nosig switch is simple enough.