Need automatic impact analysis for Shared Service with vzAny Consumer (PR #282)

[joseph-yo]

(use upvote 👍 for attentions)

Validation Type

[ ] - Fault

[ ] - Config

[ ] - Bug

[X ] - Other

What needs to be validated

Through defect CSCwi01316, there were behavior changes integrated that affect shared-services vzany consumers. Prior to the fix, vzany shared services consumers resulted in permit-all rules getting installed in the consumer vrf. After the change, individual contracts are installed for all epg pcTags that are expanded from the vzany. As a result, there can be significant tcam utilization increases when going from a version that doesn't have the fix for this to a version that does have the fix.

Why it needs to be validated

Depending on the design, if tcam utilization increases to a point where switch policy tcam is maxed out, it can cause outages. Even if it just creates a noticeable increase is used capacity, this creates confusion for both customers and TAC.

Additional context

The request here is to automate validation of the impact of these changes prior to the upgrade so customers can understand if they need to change their configuration so they aren't negatively impacted.

[takishida]

The same issue was already covered by PR #282 (Shared Service with vzAny Consumer) which already checks whether the upgrade will be impacted by this behavior change for various patterns (provider being EPG, External EPG, or ESG).

An enhancement point that was not covered by PR #282 is a quantitative analysis of how many additional Policy CAM entries will be used after an upgrade. This will be different for every single setup. Whether this is doable in this script or we should provide another script or tool separately is TBD.

With that being said, I'm changing this issue to an enhancement for now (instead of closing it).