Open Stack

On 05/02/2012 11:24 PM, Michael Still wrote:
> Hi.
>
> I'd be interested in hearing from people who have implemented some form
> of replication with glance. I'm especially interested in how you went
> about it. I attended the session at the dev summit, but that was forward
> looking, and I am pretty sure that there wasn't any mention of current
> implementations.
>
> I'll get the ball rolling -- I have just implemented API level
> replication for glance for an internal project. It uses the glance API
> to replicate images from a master glance to slave glances. Its not very
> smart at the moment, it just copies everything.
>
> Current warts:
>   - no support for metadata update
>   - no support for filtering of what is replicated
>   - maintaining amazon ec2 ids across regions requires twiddling the nova
> database where this mapping is stored
>
> Advantages of this approach:
>   - API level replication means that I can run different versions of
> glance at each end of the replication relationship
>   - it really wasn't that hard to do
>
> Would other people be interested in getting this code into glance,
> probably as a stand alone command line tool? Or has someone done
> something much better that I should be using instead?

To make your solution look incredibly complex, in TryStack, we do image 
replication with a Jenkins job that runs a two line bash script every 20 
minutes or so that rsyncs the image_data_dir from our active Glance API 
server (with filesystem backend) to our passive failover Glance API 
server. We use a simple DRBD HA setup for the MySQL server so we aren't 
concerned about the Glance registry server.

So there! I have officially one-upped your simple solution ;)

-jay

p.s. Yes, I know it's not cross-region replication, but figured I would 
get in on the conversation anyway ;)