Re: [svlogd] / -ttt / why UTC?

From: Laurent Bercot <ska-supervision_at_skarnet.org>
Date: Thu, 06 Apr 2023 11:02:53 +0000

>My boxes use TAI (international atomic time) in order to have SI-seconds and 60sec minutes and 24hrs days...

  If your system clock is set to TAI-10, then *all* the time-handling
software on your machine must be aware of it, in order to perform
time computations accurately. It is not sufficient to use the right/
time zones: a TAI-10 setup changes the interpretation of what
system calls such as time() and clock_gettime() return. It is only
possible to do this and have a consistent view of time if you control
any and every piece of software on your machine that needs to read
and display time.

  See https://skarnet.org/software/skalibs/flags.html#clockistai
for a description of the difference between "system clock set to TAI-10"
and "system clock set to UTC".

  If you're using a distribution - in your case, Void Linux - then
TAI-10 is not an option for you, unless the distribution explicitly
supports it and has built all its binaries to support it. Even if you
could make svlogd work with it, you would have trouble with other
software - this may be benign, like "date", or less so, like software
that checks the validity of X.509 certificates against certain things
like expiration dates.

  Believe me, I understand your plight, and I wish TAI-10 were the de
facto standard instead of UTC. I wish it were at least more widely
known and supported. I use it on my servers - but it comes at a heavy
price: not letting any third-party software, 99.9% of which is hardcoded
for UTC, interact with time, and only using my own tools, which support
the setup, to do that.

  I don't think you'll be able to keep running Void with a full TAI-10
setup and have everything work perfectly, at some point you'll have to
make a real choice. But right now, to superficially solve your current
issue, you could try running s6-log (from s6) in place of svlogd.
It does the same thing, but it supports TAI-10, if you build skalibs
with the --enable-tai-clock option, as described by the link above.
You probably have to build skalibs and s6 yourself: I don't think the
Void package for skalibs uses that option.

  Good luck,

--
  Laurent
Received on Thu Apr 06 2023 - 13:02:53 CEST

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