Luigi Rosa wrote:
Daniel Migault wrote on 18/07/2019 15:07:
>> Wouldn't it be nice to have an infrastructure similar to what the NTP >> pool provides for time synchronization?
My two cents of an admin of hosts (mainly Windows) that travel back and forth thru the seven seas (namely Cruise ships).
Short version: TZ sync is a pain in the arse.
Yep.
Long version. You cannot use UTC for all the hosts because, for instance, some of them show information to the guests or are used to manage crew shifts (always expressed in ship time).
On some ships the so called "master clock" has two NTP servers: one "classic" UTC and the other with ship time.
Yep. We had a customer (a cruise line) who received this solution from us. The main problem was that there were dumb date/time displays for the passengers which display whichever time they receive from the NTP server, without applying any offset. So the solution was to install an extra NTP server which provided UTC + a configurable offset for the clocks visible to passengers. And the local time offset to be applied to UTC had to be reconfigured whenever the ship enters a region with a different time zone. Of course this is an evil workaround for limitations of the time displays. Formerly there were clocks that were controlled by an IRIG time code signal which could transport lo time instead of UTC. I'm assuming the folks who developed these dump NTP clocks simply replaced the time code receiver by a network port, without keeping in mind that NTP has been designed to transport UTC only, not local time. For such dump time displays even the tzdist protocol probably won't help much. Only if the displays know about time zones the zone rules could be updated via the network, but still you had to tell each display *which* zone to use if the ship moves from one region to the next.
We cannot use ship time NTP server because NTP clients (correctly) assume that NTP is about UTC, while the local time is just a "logical view" of NTP. If we sync Windows hosts with ship time the result is a mess (somebody said "Kerberos"?).
Of course.
We concocted a simple way to sync TZ between Windows hosts.
The "TZ Server" runs the command
tzutil /g > c:\tz\tz.txt
C:\tz is shared as TZ
Every client issue the commands
set /p TZ=<\\TZSERVER\TZ\TZ.TXT tzutil /s "%TZ%"
The procedure is tested on Win2016, 2012R2 and Win10
Detailed info in my blog article: https://translate.google.com/translate?sl=it&tl=en&u=https%3A%2F%2Fsiamogeek...
The original is in Italian: https://siamogeek.com/2019/06/sincronizzare-la-time-zone/
Thanks for these interesting pointers. Martin -- Martin Burnicki Senior Software Engineer MEINBERG Funkuhren GmbH & Co. KG Email: martin.burnicki@meinberg.de Phone: +49 5281 9309-414 Linkedin: https://www.linkedin.com/in/martinburnicki/ Lange Wand 9, 31812 Bad Pyrmont, Germany Amtsgericht Hannover 17HRA 100322 Geschäftsführer/Managing Directors: Günter Meinberg, Werner Meinberg, Andre Hartmann, Heiko Gerstung Websites: https://www.meinberg.de https://www.meinbergglobal.com Training: https://www.meinberg.academy