Open Stack

On 3/19/15 9:08 AM, Jared Cook wrote:
> Hi, I'm starting to see a number of vendors push hyper-converged
> OpenStack solutions where compute and Ceph OSD nodes are one in the
> same.  In addition, Ceph monitors are placed on OpenStack controller
> nodes in these architectures.
>
> Recommendations I have read in the past have been to keep these things
> separate, but some vendors are now saying that this actually works out
> OK in practice.
>
> The biggest concern I have is that the compute node functions will
> compete with Ceph functions, and one over utilized node will slow down
> the entire Ceph cluster, which will slow down the entire cloud.  Is this
> an unfounded concern?
>
> Does anyone have experience running in this mode?  Experience at scale?
>
>

Not CEPH related, but it's a known tradeoff that compute resource on 
control nodes can cause resource competition. This is a tradeoff for the 
total cost of the cluster and the expected use case. If the use case 
plans to scale out to many compute nodes, we suggest upgrading to 
dedicated control nodes. This is higher cost, but somewhat necessary for 
matching performance to capacity.

We may start small, but we can scale up to match the (growing) needs.


-- 
-jlk