As outlined in the vSphere 7.0 release notes (which everyone should carefully read through before upgrading), the following CPU processors are no longer supported:

Intel Family 6, Model = 2C (Westmere-EP)

Intel Family 6, Model = 2F (Westmere-EX)

To help put things into perspective, these processors were released about 10 years ago! So this should not come as a surprise that VMware has decided remove support for these processors which probably also implies the underlying hardware platforms are probably quite dated as well. In any case, this certainly has affected some folks and from what I have seen, it has mostly been personal homelab or smaller vSphere environments.

One of my readers had reached out to me the other day to share an interesting tidbit which might help some folks prolong their aging hardware for another vSphere release. I have not personally tested this trick and I do not recommend it as you can have other issues longer term or hit a similiar or worse situation upon the next patch or upgrade.

Disclaimer: This is not officially supported by VMware and you run the risk of having more issues in the future.

Per the reader, it looks like you can append the following ESXi boot option which will allow you to bypass the unsupported CPU during the installation/upgrade. To do so, just use SHIFT+O (see VMware documentation for more details) and append the following:

allowLegacyCPU=true

There have also been other interesting and crazy workarounds that attempt to workaround this problem. Although some of these tricks may work, folks should really think long term on what other issues can face by deferring hardware upgrade. I have always looked at homelab as not only a way to learn but to grow yourself as an individual.

Note: The boot option above is only temporarily and you will need to pass in this option upon each restart. It looks like this setting is also not configurable via ESXCLI which I initially had thought, so if you are installing this on a USB device, the best option is to edit the boot.cfg and simply append the parameter to kernelopt line so it'll automatically be included for you without having to manually typing this. If this is install on disk, then you will need to edit both /bootbank/boot.cfg and /altbootbank/boot.cfg for the settings to passed in automatically.

This is ultimately an investment you are making into yourself, so do not cut yourself short and consider looking at a newer platform, especially something like an Intel NUC which is fairly affordable both in cost as well as power, cooling and form factor.