[Nokia-7215] Enhance Watchdog service

[Pavan-Nokia]

Mask Watchdog-control.service and make sure only one watchdog service starts on this platform

Why I did it

To resolve conflict between ordering of the 2 watchdog services.

1. watchdog-control.service -- common service designed to disable watchdog on all platforms
2. cpu_wdt.service -- enable Watchdog on nokia-7215 platform.

Is some cases service 1 was started after service 2 leaving the watchdog on the box disabled

Work item tracking

• Microsoft ADO (number only):

How I did it

Enhance service file to assure cpu_wdt.service always starts after watchdog-control.service

How to verify it

1. Try multiple upgrades and install scenario to make sure watchdog is always in enabled state
2. Try multiple reboots to make sure watchdog is always in enabled state

admin@sonic:~$ systemctl status watchdog-control.service 
â—� watchdog-control.service
     Loaded: masked (Reason: Unit watchdog-control.service is masked.)
     Active: inactive (dead)
admin@sonic:~$ 
admin@sonic:~$ 
admin@sonic:~$ systemctl status cpu_wdt.service
â—� cpu_wdt.service - CPU WDT
     Loaded: loaded (/etc/systemd/system/cpu_wdt.service; enabled; vendor prese>
     Active: active (running) since Mon 2024-05-20 14:57:15 UTC; 4min 57s ago
   Main PID: 635 (cpu_wdt.py)
      Tasks: 1 (limit: 4915)
     Memory: 13.9M
     CGroup: /system.slice/cpu_wdt.service
             └─635 /usr/bin/python /usr/local/bin/cpu_wdt.py

admin@sonic:~$ 

Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012
• 202106
• 202111
• 202205
• 202211
• 202305
• 202405

Tested branch (Please provide the tested image version)

Description for the changelog

Link to config_db schema for YANG module changes

A picture of a cute animal (not mandatory but encouraged)

[saiarcot895]

Is this guaranteed to happen before watchdog-control.service starts? If there's a chance it could be after, then add --now to have systemd stop the service as well.

[Pavan-Nokia]

I have verified all scenarios to make sure there is no race condition - fresh install, software upgrade, reboots. The watchdog-control.service is always masked correctly and the platform watchdog is active.

I have added the --now flag as recommended. I agree this is good to have in case something changes in the future

[Pavan-Nokia]

@yxieca @Blueve Please help merge and backport to 202405 branch
also help merge PR for 2311 backport #18851

Thank you

[yxieca]

@bingwang-ms to tracking 202405 cherry-picking

[mssonicbld]

Cherry-pick PR to 202405: #19236