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.

Enterprise virtualization features such as snapshots and clones allow data center managers to test system upgrades prior to production implementation. For example, these tools take the guesswork out ...

Installing Ubuntu 16.04 as a virtual machine (VM) on ESXi is a relatively simple process, provided you know how to work around some of the "gothcas" that can complicate the process. In this article, I ...