We are in the process of upgrading a vSphere 5.5 installation to 6.5U1.
vSphere 6.5U1 is our target since Veeam doesn't allow us to update to anything higher.
The vcenter upgrade to the appliance has been completed (vcsa 6.5.0 13000 Build 8024368).
Our hosts were ESXi 5.5 6480267 (should be fully upgraded by the update manager).
We are trying to upgrade these hosts to 6.5. All 3 hosts are identical.
However, after having upgraded the first host, it wouldn't return to the cluster.
I've dragged it out of the cluster and updated it some further, it is now running ESXi 6.5.0 8294253.
But it is still unable to join the EVC cluster (of which it used to be part, so it should be compatible).
The current EVC mode is Intel Nehalem.
When trying to add the host to the cluster we get the following error:
The host's CPU hardware should support the cluster's current Enhanced vMotion Compatibility mode, but some of the necessary CPU features are missing from the host. Check the host's BIOS configuration to ensure that no necessary features are disabled (such as XD, VT, AES, or PCLMULQDQ for Intel, or NX for AMD). For more information, see KB articles 1003212 and 1034926.
Please not, nothing has changed on these hosts, only ESXi has been remotely upgraded. No bios setting has been modified.
I'm starting to suspect a problem related to the Spectre patches, but have no idea how to figure this out/fix this.
Any ideas on how I can get this situation resolved?