Sync SONiC host's timezone to all containers

[gord1306]

Sync the content of /etc/timezone and /etc/localtime from the SONiC host to all containers
during their own systemd services be started.

Why I did it

The containers are not awared the timezone change in the SONiC host, it may cause some info
are inconsistent e.g. time gap between syslog and swss.rec/sairedis.rec

How I did it

In the systemd scripts of services, then timezone of containers will be sync in the postStartAction()
and therefore the containers will have same timezone after their own services are restarted

How to verify it

Change the timezone in the SONiC host and then exec the sudo config reload -y
To check the containers timezone are changed

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

• 201811
• 201911
• 202006
• 202012
• 202106

Description for the changelog

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

[gord1306]

/azpw run

[mssonicbld]

/AzurePipelines run

[azure-pipelines]

You have several pipelines (over 10) configured to build pull requests in this repository. Specify which pipelines you would like to run by using /azp run [pipelines] command. You can specify multiple pipelines using a comma separated list.

[azure-pipelines]

Commenter does not have sufficient privileges for PR 9493 in repo Azure/sonic-buildimage

[bsun-sudo]

If there is a runtime change of timezone in the host, would all running containers pick up the new timezone automatically?

[gord1306]

If there is a runtime change of timezone in the host, would all running containers pick up the new timezone automatically?

No, the timezone would not be applied automatically. It is only applied during service starting.
Users can use the command - e.g. systemctl restart systemctl restart sonic.target to make the timezone be sync to the containers

[bsun-sudo]

systemctl restart systemctl restart sonic.target

Do you mean each docker need to be restarted to sync its timezone with the host's timezone? Or only restart the services in each docker use the timezone?

[gord1306]

systemctl restart systemctl restart sonic.target

Do you mean each docker need to be restarted to sync its timezone with the host's timezone? Or only restart the services in each docker use the timezone?

Yes, the script would be executed while the service is restarted and the restarted operation includes restarting the container. It is triggered by using the systemctl restart command. If you are asking for the docker restart command only, the answer would be no. The script is not triggered to execute by the docker restart command