[openstack-dev] [puppet] [Swift] Multiple proxy recipes will create out of sync rings

McCabe, Donagh Donagh.McCabe at hp.com
Fri Jun 12 11:10:53 UTC 2015

I skimmed the code, but since I'm not familiar with the environment, I could not find where "swift-ring-builder rebalance" is invoked. I'm guessing that each time you add a device to a ring, a rebalance is also done. Leaving aside how inefficient that is, the key thing is that the rebalance command has an optional "seed" parameter. Unless you explicitly set the seed (to same value on all node obviously), you won't get the same ring on all nodes. You also need to make sure you add the same set of drives and in same order.

-----Original Message-----
From: Mark Kirkwood [mailto:mark.kirkwood at catalyst.net.nz] 
Sent: 12 June 2015 06:28
To: OpenStack Development Mailing List (not for usage questions)
Subject: [openstack-dev] [puppet] [Swift] Multiple proxy recipes will create out of sync rings

I've looking at using puppet-swift to deploy a swift cluster.

Firstly - without
I would have struggled a great deal more to get up and running, so a big thank you for a nice worked example of how to do multiple nodes!

However I have stumbled upon a problem - with respect to creating multiple proxy nodes. There are some recipes around that follow on from the site.pp above and explicitly build >1 proxy (e.g

Now the problem is - each proxy node does a ring builder create, so ends up with *different* builder (and therefore) ring files. This is not good, as the end result is a cluster with all storage nodes and *one* proxy with the same set of ring files, and *all* other proxies with
*different* ring (and builder) files.

I have used logic similar to the attached to work around this, i.e only create rings if we are the 'ring server', otherwise get 'em via rsync.




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