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

[Colin Walters <walters verbum org>]

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.