Following on from Edmund's issues... People talking about doing this typically seem to cite cgroups as the way to avoid CPU and memory related contention - has anyone been successful in e.g. setting up cgroups on a nova qemu+kvm hypervisor to limit how much of the machine nova uses?
On 1 September 2016 at 04:15, Edmund Rhudy (BLOOMBERG/ 120 PARK) <erh...@bloomberg.net> wrote: > We currently run converged at Bloomberg with Ceph (all SSD) and I strongly > dislike it. OSDs and VMs battle for CPU time and memory, VMs steal memory > that would go to the HV pagecache, and it puts a real dent in any plans to > be able to deploy hypervisors (mostly) statelessly. Ceph on our largest > compute cluster spews an endless litany of deep-scrub-related HEALTH_WARNs > because of memory steal from the VMs depleting available pagecache memory. > We're going to increase the OS memory reservation in nova.conf to try to > alleviate some of the worst of the memory steal, but it's been one hack > after another to keep it going. I hope to be able to re-architect our design > at some point to de-converge Ceph from the compute nodes so that the two > sides can evolve separately once more. > > From: matt.jar...@datacentred.co.uk > Subject: Re:[Openstack-operators] Converged infrastructure > > Time once again to dredge this topic up and see what the wider operators > community thinks this time :) There were a fair amount of summit submissions > for Barcelona talking about converged and hyper-converged infrastructure, it > seems to be the topic de jour from vendors at the minute despite feeling > like we've been round this before with Nebula, Piston Cloud etc. > > Like a lot of others we run Ceph, and we absolutely don't converge our > storage and compute nodes for a variety of performance and management > related reasons. In our experience, the hardware and tuning characteristics > of both types of nodes are pretty different, in any kind of recovery > scenarios Ceph eats memory, and it feels like creating a SPOF. > > Having said that, with pure SSD clusters becoming more common, some of those > issues may well be mitigated, so is anyone doing this in production now ? If > so, what does your hardware platform look like, and are there issues with > these kinds of architectures ? > > Matt > > DataCentred Limited registered in England and Wales no. 05611763 > > _______________________________________________ > OpenStack-operators mailing list > OpenStack-operators@lists.openstack.org > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators > > > > _______________________________________________ > OpenStack-operators mailing list > OpenStack-operators@lists.openstack.org > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators > -- Cheers, ~Blairo _______________________________________________ OpenStack-operators mailing list OpenStack-operators@lists.openstack.org http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators
