On Thu, Feb 28, 2013 at 03:18:51PM -0800, Prachi Damle wrote: > So far per the scope of the feature, Affinity groups is an entity created by > an individual account and can be used, listed only by that account. > > Wanted to know if we see any use case where one would need to create > domain-level affinity groups that all accounts in that domain can access? I > can see that this may not be useful, since users would want to have VM > placement preferences exclusive to their accounts and not shared with other > accounts. > > Any thoughts?
I spent time thinking about this, and I'm not sure I see a use-case for it. Others might though... > > -Prachi > > -----Original Message----- > From: Chip Childers [mailto:chip.child...@sungard.com] > Sent: Friday, February 22, 2013 2:00 PM > To: cloudstack-dev@incubator.apache.org > Cc: Manan Shah; Alex Huang > Subject: Re: [DISCUSS] Affinity / Anti-affinity Rules > > On Fri, Feb 22, 2013 at 01:36:20PM -0800, Prachi Damle wrote: > > Hey all, > > > > It seems that host affinity usecase has little value in reality and very > > less guarantee of success given the current deployment planning mechanism. > > > > The feature requirement says host affinity = same host. So VM's in the host > > affinity group, should get placed on the same host. But this is not > > required in most of the real applications. > > Also with Cloudstack's deployment mechanism, the affinity rules will not > > kick in for the first VM. So it may get placed on a host which has not much > > capacity left since at that point planners have no idea of the user's > > intention. Thus if a user has a set of VMS and chooses host-affinity group, > > it is possible that deployment of other VMS in the group start failing. > > > > So I am planning to not add the implementation for host affinity. Host > > anti-affinity support however is important and needed. > > > > The feature will still include: > > - framework for supporting affinity groups in general > > - Default implementation for host anti-affinity > > - DeploymentPlanningManager changes > > > > Any thoughts/comments? I will update the FS if this sounds correct. > > +1 from me. I think your analysis is spot-on. Anti-affinity is > valuable, but affinity is questionable due to it's implications. > >
