Re: gnome-continuous: speeding up "builddisks"

[Owen Taylor <otaylor redhat com>]

On Fri, 2016-09-02 at 14:55 +0200, Alexander Larsson wrote:
> On fre, 2016-09-02 at 14:52 +0200, Alexander Larsson wrote:
> > On ons, 2016-08-31 at 09:37 -0400, Owen Taylor wrote:
> > >  
> > >  1) Do the ostree operations outside the container on the host
> > >     filesystem, then copy the entire results into the container.
> > >
> > >     The main problem with this is one of filesystem ownership: as
> > >     non-root, we can't create files with the ownership that will
> > > be
> > >     needed inside the VM. It would be possible to enhance ostree
> > > to
> > >     write ownership as xattrs, and then convert when copying into
> > > the
> > >     VM, or to even have ostree directly stream a tarfile to be
> > > unpacked
> > >     in the VM, but either would be significant work.
> >
> > This is what the "bare-user" repo format does. Its writable as a
> > regular user, but loses no fidelity wrt things like permissions.
> > And yes, it does work by storing the permissions in the xattrs.
> >
> > This should work well, as its the primary format that flatpak uses
> > for its repositories (both to support user installs, and to avoid a
> > remot ostree repo setuid file actually being stored setuid in the
> > object store).
>
> Oh, and once the repo is done you can export it as a tar file with
> "ostree export".

Good to know. For right now, fakeroot is working pretty well, and
provides a complete solution where I can pull and 'ostree admin deploy'
and copy the results into VM with tar propagating hard links correctly
between the two, but it sounds like some of the stuff that we'd need to
use an xattr-based solution is already there in ostree.

- Owen