[chassis][202405]: snmp service enters failed state during test_pfcwd_basic_single_lossless_prio_service_restart test

[anamehra]

Description

The changes in sonic-net/sonic-mgmt#13483 fixes an issue with swss restart test case for multiasic.
After this change we ar eobserving failure on multiasic DUTs as multiple swss services are restarted.

With every swss service restart, snmp service also gets restarted and this causes snmp service to enter the failed state.

The test case does not bring snmp service out of failed state and restart it.

This causes subsequent test cases to fail as snmp doe snot run.

1. snmp service has Requisite=swss in unit file. As per systemd documentation, this should not cause snmp to restart on swss restart but it does on debian. Need to check if its a bug in debian. We need to understand what i sthe expected behavior for Soni in this scenario. Do we expect snmp to restart on swss resart? If yes, what is the reason?
2. If snmp restart is expected, the test case needs to be fixed to handle this scenario.

Steps to reproduce the issue:

Describe the results you received:

Describe the results you expected:

Output of show version:

(paste your output here)

Output of show techsupport:

(paste your output here or download and attach the file here )

Additional information you deem important (e.g. issue happens only occasionally):

[anamehra]

Hi @abdosi , @stepanblyschak

As per comments in #2790, snmp restart is expected. Is that condition still true? Please suggest.

[arlakshm]

Can we handle this in the test to reset the snmp service for short term. For long term fix, we need to investigate if the snmp services needs to restart on swss restart