APIC 6.0 upgrade

[mannycho]

Hello,

our current ACI fabric is running 4.2(7), 14.2(7) and we want to upgrade to 6.0(2). Existing spine and leaf switches hardware are not compatible with 16.0(2). Can i upgrade the APIC only from 4.2(7) to 6.0(2) and leave the fabric switches in their 14.2(7) code? This will be a temporary state until we replace the hardware for the spines and leafs. What are the drawbacks and caveats of doing this. Thank you

[RedNectar]

Hi @mannycho ,

I’d recommend not doing that, especially if you have any filters defined, and in particular a filter for TCP port 22.  I explained how filters that allow TCP Port 22 get transformed into filters that allow ALL traffic in a blogpost back in 2020

That post vas referring to v5, but the story is the same for v6.  Now, that was jus ONE example.  There may be others. And if the filters have already been pushed to the switches you should be OK (Not sure what happens if a switch reloads though. That might be a problem)

[mannycho]

Thanks Chris, the fabric is in network centric mode currently, all traffic allowed between the EPGs. Outside of the filters concerns, can you think of others?

Thanks

[RedNectar · Accepted solution]

@mannycho ,

That's all I KNOW of - but I'd be very wary about having a mix of versions.  In my (overall networking) experience, many weird problems get solved by making sure software versions are synced.  My advice is still - don't upgrade to APIC v6.x until all switches are in place that support v6.x

If you REALLY want to go ahead, start by contacting TAC to see if they will support you if things go pear shaped.

[Robert Burns · Accepted solution]

No issues from a support perspective running leafs in the fabric with different versions.  I would support Chris' statement about limiting this where possible.  The APIC is fully backwards compatible, but one word I advice, if you need to run a mixed version switch fabric, don't enable any "new" features in the fabric (available to the higher verison switches only) during the migration period.   The APIC and fabric are intelligent enough to understand that certain features sometimes require certain versions of switch software to resolve/push the config, but there's also the possibility of behavior changes with existing features (supported by old & new software versions) that could cause issues.  This is rare, but keeping everything consistent as much as possible limits these instances.

Robert