Recently I had to upgrade our ESXi hosts from Update 2 to Update 3 due to security patch requirements. This requirement stretches across two separate physical environments, one running IBM blades and the other running on Cisco UCS blade chassis in a Flexpod configuration. The upgrade paths for both are slightly different, and they also run on different vCenter platforms. Both of these also have different upgrade paths as one is running VMware SRM and is in linked mode. I’m not going to discuss the IBM upgrades but I did need to upgrade the firmware of the Infrastructure and Servers for Cisco UCSM.
Before you being any upgrade process I highly recommend reading the release notes to make sure that a) an upgrade path exists from your current version, b) you become aware of any known issues in the new version and c) the features you want exist in the new version
UCS Upgrade Prep Work
Check the UCS Release Guides
Check the release notes to make sure all the components and modules are supported. The release notes for UCS Manager can be found on their site. The link is listed further below in the documents section.
Some of the things to check within the release notes are:
* Resolved Caveats

- UCS Version Upgrade patch

- UCS Infrastructure Hardware compatibility

- Minimum software version for UCS Blade servers

Open a Pre-Emptive Support Call
I opened a call with Cisco TAC to investigate the discrepancy in the firmware versions. The advice was to downgrade the B200 M4 server firmware down to 4.0 (1). However, as I was planning on upgrading anyway I’ve now confirmed that the best option is to upgrade to the planned 3.1 version. As part of this upgrade I will also upgrade all the ESXi hosts on that site the same day. There is a second UCS domain on another site that will be upgraded on another date.


On further investigation I found that this is a known bug when upgrading to versions 2.2(2) and above. I was upgrading from version 2.2(1d) to 2.2(3d). Despite being a critical alert the issue does not impact any services. The new UCSM software is looking for new features on the FI that do not exist yet as it has not been upgraded. As soon as you upgrade the FIs this critical alert will go. More information about the bug can be found Cisco’s support page for the bug