Questions

[John Arbash Meinel]

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>> Most of the coordination with mongodb in juju-core is done with 
>> watchers and mgo transactions. Since juju is a distributed
>> system aiming to scale to 100K nodes or more there are a lot of
>> issues with concurrency and race conditions, we need a central
>> place to sync what juju knows about the environment and get
>> notified about changes.
> 
> Can you give an example of the type of an application driving juju
> to a single 100K node environment? Even with the kind of scale-out
> ARM servers are promising, you're talking about a single
> application that is driven into 100 racks of 1000 servers each. If
> you were talking about OpenStack, that would be a single region
> with 100K servers in it.
> 
> Might want to provide some safeties on destroy-environment for
> those apps... ;)
> 
> I'm not sure 100K is a worthy goal, but perhaps you have something 
> specific in mind.
> 

I think one of the drivers is using Juju-on-MaaS to control the raw
hardware that drives the Openstack above them which is then presented
to end-users as a Cloud. So you end up with a lot of nodes that are
very similar. I think 100k is still pie-in-the-sky, but ~10k is things
people are thinking about right now, so making sure your design
doesn't fall over too quickly is worthwhile.

John
=:->
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