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With respect to using a seed - the facility to supply one to the 
rebalance operation has recently been added to puppet-swift master 
branch (commit b8b4434), however the seed parameter is not available to 
any of the usual calling methods (this looks to be deliberate from the 
commit message), so is not immediately useful without surgery :-)

Regards

Mark

On 13/06/15 18:05, Mark Kirkwood wrote:
>  From what I can see, the ring gets created and rebalanced in
> puppet-swift/manifest/ringbuilder.pp i.e calling:
>
>    class { '::swift::ringbuilder':
>      # the part power should be determined by assuming 100 partitions
> per drive
>      part_power     => '18',
>      replicas       => '3',
>      min_part_hours => 1,
>      require        => Class['swift'],
>    }
>
> *not* when each device is added.
>
> Yeah, using a seed is probably a good solution too. For the moment I'm
> using the idea of one proxy being a 'ring server/master' which achieves
> the same thing (identical rings everywhere). However I'll have a look at
> using a seed, as this may simplify the code and also the operational
> procedure needed to replace said 'master' if it fails (i.e to avoid
> accidentally creating a new ring when you really don't need to...)
>
> Regards,
>
> Mark
>
> On 12/06/15 23:10, McCabe, Donagh wrote:
>> 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.
>>
>> Regards,
>> Donagh
>> -----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
>> http://git.openstack.org/cgit/stackforge/puppet-swift/tree/tests/site.pp
>> 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
>> https://github.com/CiscoSystems/puppet-openstack-ha/blob/folsom_ha/examples/swift-nodes.pp)
>>
>>
>> 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.
>>
>> Thoughts?
>>
>> Regards
>>
>> Mark
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