VMware ESXi is an enterprise-class, type-1 hypervisor developed by VMware for deploying and serving virtual computers by integrating vital OS components, such as a kernel; since as a type-1 hypervisor ...

Does the server have light-out mgmt? You can upgrade the BIOS via that. That takes care of the host. ESXi updates can be done through a vCenter.

The best operating system is one you don't have to reinstall often.