start a new service to configure TSA as soon as Linecard comes up, start a timer to configure TSB and configure TSB when timer expires

[saksarav-nokia]

Why I did it

The traffic loss is seen when the chassis or Linecard is rebooted . Cloning the https://github.com/Azure/sonic-buildimage-msft/pull/206 to master

Work item tracking

• Microsoft ADO (number only):

How I did it

Start a service startup_tsa_tsb.service when the IMM comes up This service configures TSA and starts a timer which is provided in device/startup-tsa-tsb.conf for every platform. This service will exit with NOP if the platform doesn't have startup-tsa-tsb.conf in the device folder. If the CONFIG_DB has TSA configured already, the service will exit. When the timer expires, TSB is configured Enhanced "sudo TSC" command output to indicate TSB pending with the remaining timer value and service name if the service is running If the operator issues "sudo TSA" explicitly while the startup_tsa_tsb.service is running, service will be stopped.

How to verify it

Verified that the service is started only in IMM Verified that the service runs only if device/startup-tsa-tsb.conf file exists Verified that the TSA is configured and routes are not advertised to eBGP neighbors till TSB timer expires and TSB is configured. "sudo TSC" shows the TSB Pending with remaining timer interval Service is stopped when the operator issues "sudo TSA"

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

• [ ] 201811
• [ ] 201911
• [ ] 202006
• [ ] 202012
• [ ] 202106
• [ ] 202111
• [ ] 202205
• [ ] 202211
• [ ] 202305

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)

[saksarav-nokia]

@sanjair-git for viz

[saksarav-nokia]

@rlhui @arlakshm @judyjoseph @abdosi @deepak-singhal0408 Created this PR for master

[saksarav-nokia]

@gechiang , I have update the master PR with the fix

[saksarav-nokia]

@abdosi , could you please restart the azure pipeline?

[wumiaont]

/azpw run Azure.sonic-buildimage

[saksarav-nokia]

@judyjoseph , @lguohan @abdosi , could you please review and merge it?