Re: [PATCH] sstate.bbclass: preserve time when unstaging files

[Enrico Scholz <enrico.scholz@sigma-chemnitz.de>]

Richard Purdie <richard.purdie@linuxfoundation.org> writes:

>> >> >> But the real bug is the time mismatch in the autobuilders, isn't it?
>> >> >> And this can/should be solved by synchronizing time by ntp on them
>> >> >> instead of applying dirty hacks like resetting file dates.
> ...
> Imagine system A generates the sysroot headers with a time ahead of
> system B. These are packaged up into an sstate tarball. System B which
> has a clock at some time behind system A then downloads and uses them
> so the sysroot headers become some time in the future.

This can not happen when both machines are synchronizing their time with
ntp.  Drift to stratum-1 machine is usually <1ms in local networks and
<50ms for remote ones (--> see 'ntpq' -> pe output).

Nothing, which can cause the problem described by you.


> The alternative is to mandate *every* system that builds are run on
> use ntp

Yes; a common timesource is mandatory for so nearly every distributed
system.  Even windoze enables (s)ntp clients by default (although its
daily synchronization is just a bad joke) and I remember Fedora/Ubuntu
enabling it by default too.


> and add checks to sanity.bbclass to this effect since someone might
> try using a sstate feed with a bad clock. This would cause no end of
> problems, not least with corporate filewalls

Every non-trivial network has local ntp servers which are used by clients
there.


> and hurt usability of the project

How common is the distributed autobuilder setup?  How many of these
installations do not use ntp?



Enrico