Hey folks,
we are planning to upgrade our Nexus 5500 devices from 5.2(1)N1(2a) (via the intermediate release 7.0(4)N1(1) ) to 7.1(5)N1(1).
This is a classic VPC design, so the upgrade should be straightforward.
However, we are unsure about what TAC considers a supported topology.
We are aware that while upgrading a single node we first need to upgrade it to 7.0(4)N1(1) and only then can upgrade to 7.1(5)N1(1). We are aware that we have to follow the respective upgrade guides on CCO.
We would like to upgrade Nexus Node "A" first, from 5.2(1)N1(2a) through 7.0(4)N1(1) ) to finally get to 7.1(5)N1(1). Then we would like Node "A" in 7.1(5)N1(1) to work in VPC together with Node "B" still in 5.2(1)N1(2a), and then (after like a week or so) execute the same procedure on Node "B".
Now there is a bit of confusion about:
- is VPC supposed to work fine with 5.2(1)N1(2a) on Node B and 7.1(5)N1(1) on Node A for a limited amount of time
- does TAC support us if there are any issues in this transitional phase, while some of the nodes are still in 5.2(1)N1(2a) (because there is no ISSU compatibility between 5.2(1) and 7.1(5))
- how does ISSU release compatibility (from the upgrade guidelines) impact VPC compatibility between different nodes (in different releases) - both from a technical point of view and also from a TAC support point of view
We cannot end up with a situation where TAC won't support us, because one node is in 5.2 and the other is in 7.1, not even if that's "only" a transitional phase.
The alternative would be to upgrade all nodes to 7.0(4)N1(1), and only when all nodes run 7.0(4)N1(1) we continue with the second phase of the upgrade, which is the jump to 7.1(5)N1(1). This would however double the risk of hitting new bugs, as we would run a 2 new distinct releases in production for some time (and it would also be twice the effort).
It would be great if a TAC engineer could clarify the support situation in this case.
Thank you so much,
Lukas
