[Linuxptp-users] UTC offset change when loosing grand master

[Boris B. <bor...@gm...>]

Hi all,

I have a system with a grand master clock that is GPS synchronized (secure
sync),
a SERVER machine running Linux/ptp4l acting as boundary clock for set of
CLIENTS systems.

The SERVER and the CLIENTS behind it requires precise time synchronization,
hence
the usage of PTP.

The grand master is aware that the current UTC offset is 37s today.

My SERVER on the other hand, is built with a code base from 2016 and think
the UTC offset is 36s. But as long as the grand master is present, the
boundary clock
distribute time with the correct offset.

The problem is, if the grand master is lost (power failure, network
issue....), my boundary
clock promotes itself as grand master, and uses its own knowledge of the
UTC offset instead
of the last known offset from the secure sync, and this cause a 1s step on
the UTC time !

This change propagate to the CLIENTS and also to the system clock of the
SERVER via phc2sys.
And during 1 or 2 minutes, the system clock of the SERVER and the CLIENTS
are not fully synchronized,
causing the system to fail to provide its service.

Looking at the documentation, I can't find any way of updating the UTC
offset of the SERVER in a simple
manner.

Rebuilding the SERVER with a new code base each time a new leap second is
inserted is not an option (the system
once deployed can not be updated easily).

What are my options ?

Thank you in advance for your advice !

Boris Boucher