Replacing APIC in cluster but new APIC has different software version

[vv0bbLeS]

Hello all,

I'm refreshing my generation L2 APIC's with new generation L4 APIC's. My current L2 APIC's are running ACI version 5.2(5c). The new APIC's from Cisco were shipped with version 6.0 on them as that was my only choice of software version in the Build and Price tool. : )

To downgrade the 6.0 software version on the new L4 APIC's to match the existing cluster software version of 5.2(5c), I'm guessing I will need to do a 5.2(5c) .iso file boot from my Cisco USB drive on the new APIC's? Or is there some way to do the software downgrade on a new APIC in the ACI GUI? I read here that for the new APIC to join the cluster it needs to be running the same software version as the cluster, so it seems like the .iso file boot option is my only option? Just wanting to be sure I do this the "best" way. : )

[Hefe2 · Accepted solution]

Hi @vv0bbLeS 

the new apics have to run the same software version as the existing cluster, otherwise the new apic won´t fully join the fabric (had this issue a few months ago)

Best way  is to map the new ISO file using SOL (Serial Over LAN) via CIMC access (section "Installing Cisco APIC Software Using CIMC Virtual Media). Take a look here

Regards

[Robert Burns · Accepted solution]

For what it's worth, from 6.0(2)+ , you can now join an APIC to the cluster with a different version, and it will auto-update the new controller's firmware to match the cluster's.  No user intervention necessary.
https://www.cisco.com/c/en/us/td/docs/dcn/aci/apic/all/apic-installation-aci-upgrade-downgrade/Cisco-APIC-Installation-ACI-Upgrade-Downgrade-Guide/m-auto-firmware-update.html#:~:text=on%20Switch%20Discovery-,Auto%20Firmware%20Update%20on%20APIC%20Dis....

Robert

[a12288]

Hi, @Robert Burns In this situation, will Cisco suggest customer upgrade M2 to 6.0 then replace M2 with M4, or downgrade M4 to 5.2 then replace M2 with M4?

5.2 is quite stable and I would like to stay on 5.2 and replace M2 with M4 at first, then consider upgrade M4 from 5.2 to 6.0 later on, is it any support issue down the road (downgrade M4 to 5.2)? Thanks.

Leo

[Robert Burns]

Gen4 APICs are only supported with 6.0(2)+ or 5.3 (releasing before EOY).  Gen4s will NOT be supported on any 5.2 release.  The reason is Gen4 APICs use a new OS (kernel) which adds support for the new processors (AMD) used by Gen4 controllers. To support this we are moving to Ubuntu (away from CentOS). Due to this change the Engineering felt it was not in line with the maintenance release designation to have a major OS change. 5.3 is essentially a clone of 5.2(8) but with the APIC OS update.  There was alot of debate if Gen4 APIC support would be released with a 5.2(9) or 5.3 release numbering.  We decided on the latter.

I would advise to wait until 5.3 releases in the next couple of months as its the closest thing to 5.2(8) today which will just add support for your Gen4 APICs.  This would be an exception where I would recommend moving to a high sub-major release (5.2 > 5.3).  It will be limited with changes/features (outside of the kernel changes) compared to going up to 6.x which has a slew of new enhancement and features.  When 6.0 goes into maintenance mode (around the 6.0(5)M timeframe, then I would advise folks to migrate to the 6.x release.

Hope this helps,

Robert

[vv0bbLeS]

Thanks for the question @a12288 ! And thanks for the reply @Robert Burns ! So for my APIC-SERVER-L4 and M4 models (Gen4 APIC's), I would need to have my existing Gen2 APIC cluster running either 5.3 (not released quite yet) or 6.0(2)+ , as a Gen4 APIC will NOT run on anything 5.2. Per your reply, if we like the current 5.2 release, it's advised to upgrade to 5.3 when it's released.

For upgrading to 6.0(5)M , I thought it was best to wait until an ACI version is declared "long-lived" , i.e. I should wait for 6.2 before upgrading to the 6.x major release train?

[Robert Burns]

@vv0bbLeS   from 6.x onward there's no more concepts of Long Lived/Short Lived releases.  Everything is released on a standardized cycle now.  This should help with more accurate forecast of upgrade cycles & LCM.
Releases 1-3 of any new major version will typically be Feature releases. ie. 6.0(1)F, 6.0(2)F, 6.0(3)F etc
Releases 4+ will typically be Maintenance releases. 6.0(4)M, 6.0(5)M etc
Following the new cycle I would equate the first 'M' release as the safest to migrate to for a major new version. 

Robert

[vv0bbLeS]

@Robert Burns ah ok great! Very cool. That does look like a good improvement over the current long-lived/short-lived system, bringing ACI software version designations in-line with how NXOS versions are already designated (F = "Feature Release" and M = "Maintenance Release" ). Thanks again!

[a12288]

Thanks for the detailed explanation, appears lots of hard working in Cisco dev. To summary we are better off on this direction : 5.2 -> 5.3 -> 6.0.xM.

By the way, what is the EoL of 5.2? 

Leo

[Robert Burns]

Exactly right Leo.

EoL  for 5.2 I'm guessing will be sometime next year.  This is based on a release being announced EoL around 3-4 years from GA.  Beyond the EoL, you'll have another 2-3 years until Last Day of Support (LDoS).

So there's plenty of time left with 5.2 train, barring you don't need support for the new controllers and/or hardware platforms.

Robert

[vv0bbLeS]

@Hefe2 and @Robert Burns thank you all so much! I have a lab environment so I will see if the APIC shipped with version 6.0(2) or above and if so I will try the auto-upgrade feature. If that doesn't work I will try the SOL suggestion. Thanks again!