Cisco Custom Image for ESXi: relationship between OS and Firmware SWs

[battagls]

Hello.

The latest Cisco Custom Image for ESXi released is 7.0 U3o. The full name of the download file is "VMware-ESXi-7.0.3o-22348816-Custom-Cisco-4.3.2-a.1.iso". Does the “Cisco-4.3.2-a.1” in the file name indicate the firmware that needs to be installed on the server before proceeding with the installation of this Cisco Custom Image for ESXi? 

Currently on our servers the firmware version installed is 4.2(3) and I wanted to understand if I need to proceed with the firmware upgrade before upgrading the ESXi.

Thank you.

Sergio

[Riaan van Niekerk]

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 “Does the “Cisco-4.3.2-a.1” in the file name indicate the firmware that needs to be installed on the server before proceeding with the installation of this Cisco Custom Image for ESXi?”

It indicates the server firmware bundle that is compatible/certified with the enic, fnic and other drivers included in the custom ISO.

If you do a clean install, I would upgrade the firmware to the newer version before installing, like you mentioned,

[Riaan van Niekerk · Accepted solution]

"Currently on our servers the firmware version installed is 4.2(3) and I wanted to understand if I need to proceed with the firmware upgrade before upgrading the ESXi."

They need to match (as discussed). However, in my experience

• Newer firmware with older drivers cause issue (e.g. there may be new features introduced in newer firmware that the older drivers do not recognise. This may not immediately be aparent, but may manifest itself when paths go down or under certain failure scenarios..
• Newer drivers with older firmware: I have never seen an issue with this combination.

If you cannot upgrade server firmware at the same time as drivers and ESXi (e.g. have the firmware upgrade pending on next reboot), I would strongly recommend that you upgrade drivers first (with / without ESXi) before upgrading server firmware. 

For clean installs, it does not matter which you do first, as long as they match when you take the environment live.

[battagls]

Hello.

Thank you very much for your replies and sorry for the delay in replying.

I will try to summarize what you wrote to me:
If I understand you correctly, the words “Custom-Cisco-4.3.2-a.1” in the ESXi ISO file name (“VMware-ESXi-7.0.3o-22348816-Custom-Cisco-4.3.2-a.1.iso”) means the fw of the Cisco UCS servers certified with that OS version (in this case ESXi-7.0 Update 3o). And so it is advisable (if not mandatory) to keep fw and OS (driver) aligned.

Anyway, based on your experience, it is possible to have a newer OS (which means newer drivers) with an older UCS server fw (even though it is not the solution recommended/supported by Cisco). So, in my case I could upgrade the ESXi to version 7.0 Update3o (currently 7.0 Update3i is installed) and keep the UCS server fw to version 4.2. Is what I wrote correct?

Kind Regards.

Sergio

[Riaan van Niekerk]

It is possible to run newer drivers (certified with 4.3 firmware) with older (4.2) firmware and you should be OK. However you will not be in line with the Cisco compatibility matrix.

If you run into any issues, please let me know, Cisco will ask you to run a certified combination, e.g. Upgrade firmware (the easier one, and my recommendation) or downgrade drivers.

Our organisation (800+ UCS servers) sticks to the compat matrix as far as possible. Most of the time if Cisco pick up an issue, it is with the fnic driver being slightly out of date (or still supported/certified, but not the latest certified driver) and Cisco recommends we upgrade.