chore: disable default dynamic var snappi fallback

[auspham]

Description of PR

Summary: Disable the default dynamic variable snappi fallback since T1-tgen testbed does not support this feature yet and currently generating alert. Disabling this now to suspress the alert.

Fixes # (issue) 33123296

Type of change

• Bug fix
• Testbed and Framework(new/improvement)
• New Test case
  • Skipped for non-supported platforms
• Test case improvement

Back port request

• 202205
• 202305
• 202311
• 202405
• 202411
• 202505

Approach

What is the motivation for this PR?

Disable the default dynamic variable snappi fallback since T1-tgen testbed does not support this feature yet and currently generating alert. Disabling this now to suspress the alert.

@sdszhang @kamalsahu0001 @amitpawar12 for viz

How did you do it?

How did you verify/test it?

Any platform specific information?

Supported testbed topology if it's a new test case?

Documentation

[sdszhang]

lgtm

[yejianquan]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[yejianquan]

LGTM

[mssonicbld]

Cherry-pick PR to 202505: #18813

[sdszhang]

@amitpawar12 for viz.

[vkjammala-arista]

Hi @auspham, these changes doesn't look right to me and is causing regression for T0 (tgen-t0-3).

if the testbed data is not there in snappi_tests/variables.override.yml, we want dynamic port selection to happen as per HLD but the code changes are doing opposite. Can you explain why we made this change (sounds like this is temporary fix for T1 but we shouldn't left T0 broken)?

[auspham]

Hi @vkjammala-arista, we haven't officially support dynamic port selection for t0/t1 yet so we temporary disable it. Does variables.override.yml not working for your end?

[vkjammala-arista]

we haven't officially support dynamic port selection for t0/t1 yet so we temporary disable it.

I'm not aware that dynamic port selection isn't supported for t0/t1 (thus , as I saw tgen_port_info fixtures being used I expected it to work. Any known issues here?

I had run tests with this PR changes reverted, i don't see any obvious issues with dynamic port selection though.

Does variables.override.yml not working for your end?

I got to know about this file very recently, and thought this is not needed with dynamic port selection enabled.

[auspham]

I'm not aware that dynamic port selection isn't supported for t0/t1 (thus , as I saw tgen_port_info fixtures being used I expected it to work. Any known issues here?

It supposed to support t0/t1 as well, however when we saw some issue that blocking us to run the test so we toggle it off for t0/t1 and marking this as a todo come back and investigate using this PR.

I got to know about this file very recently, and thought this is not needed with dynamic port selection enabled.

Yes it is supposed to behave this way.

If we revert this PR here does it work from your end?

[vkjammala-arista]

If we revert this PR here does it work from your end?

Yeah, atleast port selection seems fine (snappi_ports are populated correctly as per test requirements).

It supposed to support t0/t1 as well, however when we saw some issue that blocking us to run the test so we toggle it off for t0/t1

What type of issues you were seeing, do you have some logs/written documents somewhere that I can check. Thanks!

[auspham]

We saw something like this on T0 T1

[vkjammala-arista]

We have seen this failure and looking more into this, but atleast as per my understanding this failure doesn't have anything to do with dynamic port selection (as the code path setup_dut_ports is common for both dynamic port selection and static port selection)

Did you confirmed that the failure is related to dynamic port selection? and you're not seeing this failure after switching to static port selection?

[kamalsahu0001]

Error mentioned by @auspham is different and is not related to dynamic ports selection. That error comes when all three sections are enabled under snappi_fixtures.py code. In general, it should check for either of them. But if we enable, all three it will complain about vlan interfaces not configured, if the DUT has routed ports instead of vlans. If there are no vlans, then we can comment that section in snappi_fixtures.py. Attaching the snapshot for reference.

[sdszhang]

@vkjammala-arista is the snappi test cases passing for you without dynamic-port-selection?