Re: SSL for screenshots.debian.net?
On Wed, 12 Feb 2014, Christoph Haas wrote:
> > Have you given any consideration into making this service
> > mirrorable? I.e. have one master instance through which updates are
> > added, and more hosts that can then serve the content to
> > end-users?
>
> Yes, I have. The challenge would mainly be the storage backends.
> PostgreSQL has been my favorite database. But replication was an issue
> as all mirrors would have to be able to write and send their updates
> to other servers. Besides the actual image (PNG) blobs would have to
> be copied, too. So I wondered if I have to implement replication on an
> application layer.
> Simple mirrors would work in a master/slave fashion. But that is not
> the concept of using a common screenshot database for multiple
> distributions.
I was thinking of redirecting all udpates to
https://screenshots-master.debian.org/, but serve the "normal" queries
from https://screenshots.debian.org/. The -master is on a single host,
the screenshots site could be replicated, i.e. a round robin of several
machines.
If you use pg and a filesystem as your storage backends, we can
replicate the database pretty much instantly - the non-master clients
will only need read-only access. The filesystem tree could just be
replicated using rsync - for bugs.d.o we use a inotify based rsyncing
strategy that runs an rsync over new/changed files within the minute
they happen.
This is, of course, not fully replicated as the -master hist is still a
SPOF. But if that goes down we only lose the ability to add new
screenshots, not the ability to serve them. Also, it seems like it
ought to be relatively simple and straight forward, but then I don't
know the intricate details of screenshots.d.n.
Cheers,
--
| .''`. ** Debian **
Peter Palfrader | : :' : The universal
http://www.palfrader.org/ | `. `' Operating System
| `- http://www.debian.org/
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