Re: [atomic-devel] Changing /etc/localtime with container images

[Daniel J Walsh <dwalsh redhat com>]

On 12/08/2016 01:30 PM, Colin Walters wrote:
>
> On Wed, Dec 7, 2016, at 04:14 PM, Daniel J Walsh wrote:
>
>> docker run -ti -v /etc/localtime:/etc/localtime:ro fedora bash
> One problem with this (and in general, any host <-> container binds)
> is that one needs to consider format versioning.
>
> Right now glibc is on its second version of the timezone database format.
> For reasons I forget now, for example we parse it in glib:
> https://git.gnome.org/browse/glib/tree/glib/gtimezone.c?id=1ef807445c3c2f1b03cfd5beea8d58a74ba96ef1#n453
>
> And obviously glibc does - so we could get into a situation where
> if the host revs more quickly than the container (as is a primary use
> case particularly for Atomic Host), then containers suddenly fail
> to set timezones after a host upgrade.
>
> Long term, I think we'll need an architecture where the container
> talks to the host via APIs - so in this case the host would provide
> the container with a version of the timezone database that it
> understands.
>
This is an argument of not doing the -v
/etc/localtime:/etc/localtime:ro, but I am not sure if this
says anything about whether or not we should carry the TZData inside of
the container image.