[systemd-devel] [PATCH 3/3] nspawn: allow to bind mount journal on top of a non empty container journal dentry

[Djalal Harouni]

On Fri, Apr 25, 2014 at 08:30:36PM +0200, Tom Gundersen wrote:
> On Fri, Apr 11, 2014 at 2:45 AM, Djalal Harouni <tixxdz at opendz.org> wrote:
> > Currently if nspawn was called with --link-journal=host or
> > --link-journal=auto and the right /var/log/journal/machine-id/ exists
> > then the bind mount the subdirectory into the container might fail due
> > to the ~/mycontainer/var/log/journal/machine-id/ of the container not
> > being empty.
> >
> > There is no reason to check if the container journal subdir is empty
> > since there will be a bind mount on top of it. The user asked for a bind
> > mount so give it.
> >
> > Note: a next call with --link-journal=guest may fail due to the
> > /var/log/journal/machine-id/ on the host not being empty.
> >
> > https://bugs.freedesktop.org/show_bug.cgi?id=76193
> 
> Hm, so this will allow some journal entries to be saved on the host
> and some on the guest, but only one of them
> will be shown by "journalctl --merge" at any given time... Won't this
> be confusing? Either way I guess this case
> should be documented in the manpage (either that it is not allowed, or
> that it may be confusing)...
Yes, to be honest, I'm also not sure! but I guess if the user wants to
move to the host, perhaps give him a chance, or at least document as you
have suggested, and warn during systemd-nspawn (will verify it later). 

So I'll wait to see what others think, or perhaps extend journalctl to
make this part of --merge ... ?

Thanks!

> > Reported-by: Tobias Hunger <tobias.hunger at gmail.com>
> > ---
> >  src/nspawn/nspawn.c | 5 -----
> >  1 file changed, 5 deletions(-)
> >
> > diff --git a/src/nspawn/nspawn.c b/src/nspawn/nspawn.c
> > index 21322f7..afb003c 100644
> > --- a/src/nspawn/nspawn.c
> > +++ b/src/nspawn/nspawn.c
> > @@ -1152,11 +1152,6 @@ static int setup_journal(const char *directory) {
> >          } else if (access(p, F_OK) < 0)
> >                  return 0;
> >
> > -        if (dir_is_empty(q) == 0) {
> > -                log_error("%s not empty.", q);
> > -                return -ENOTEMPTY;
> > -        }
> > -
> >          r = mkdir_p(q, 0755);
> >          if (r < 0) {
> >                  log_error("Failed to create %s: %m", q);
> > --
> > 1.8.5.3
> >
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-- 
Djalal Harouni
http://opendz.org