Open Stack

On Wed, 2022-02-16 at 10:52 +0100, Franck VEDEL wrote:
> Thank’s a lot ! 
> I changed the settings and indeed, it seems to work. This distribution of instances is really interesting. I learn a lot.
> Question: is it possible to view the calculated weight when choosing a server?
> Otherwise, thanks again, really
yes this is logged in the schduler at debug level
> 
> Franck
> 
> > Le 16 févr. 2022 à 03:35, Tony Liu <tonyliu0592 at hotmail.com> a écrit :
> > 
> > Build failure could be caused by different things, networking, storage, hypervisor, etc.
> > For example, failure caused by Neutron service, that doesn't mean this hypervisor is
> > not healthy, but because of that weigher, even Neutron service is recovered, this
> > hypervisor is still excluded from holding instance. This doesn't make sense.
> > I wouldn't enable this weigher until it's smart enough to know the failure is caused
> > by hypervisor itself, but not anywhere else.
> > 
> > Tony
> > ________________________________________
> > From: Laurent Dumont <laurentfdumont at gmail.com>
> > Sent: February 15, 2022 05:00 PM
> > To: Tony Liu
> > Cc: Franck VEDEL; openstack-discuss
> > Subject: Re: [kolla-ansible][nova]Problem with distribution of instance on servers
> > 
> > In a healthy setup, should build_failure_weight_multiplier be triggered?
> > 
> > From the doc, tweaking this might mean you try to schedule and built instances on computes that are not healthy.
> > 
> > On Tue, Feb 15, 2022 at 6:38 PM Tony Liu <tonyliu0592 at hotmail.com<mailto:tonyliu0592 at hotmail.com>> wrote:
> > Enable debug logging on nova-scheduler, you will see how the winner is picked.
> > I had the same issue before, caused by the build-failure weigher enabled by default.
> > setting build_failure_weight_multiplier to 0 resolved issue for me. Instances are
> > balanced by weighers (compute and memory) as expected.
> > shuffle_best_same_weighed_hosts and host_subset_size are not necessary, unless
> > it's required by certain cases.
> > 
> > Tony
> > ________________________________________
> > From: Laurent Dumont <laurentfdumont at gmail.com<mailto:laurentfdumont at gmail.com>>
> > Sent: February 15, 2022 12:54 PM
> > To: Franck VEDEL
> > Cc: openstack-discuss
> > Subject: Re: [kolla-ansible][nova]Problem with distribution of instance on servers
> > 
> > There are two settings we've tweaked in the past in Nova.
> > 
> > shuffle_best_same_weighed_hosts  --> Allow more spreading in the case of computes with the exact same specs/weights.
> > host_subset_size --> Helps with concurrent requests to get different hosts
> > 
> > Before that, we saw the same behavior with Openstack stacking VM on single computes. It still respects anti-affinity, but I don't see a good reason to not spread as a default. Changing these two was enough to allow our spread to get a little better.
> > 
> > On Tue, Feb 15, 2022 at 11:19 AM Franck VEDEL <franck.vedel at univ-grenoble-alpes.fr<mailto:franck.vedel at univ-grenoble-alpes.fr><mailto:franck.vedel at univ-grenoble-alpes.fr<mailto:franck.vedel at univ-grenoble-alpes.fr>>> wrote:
> > Hello,
> > I seem to have a problem that I hadn't seen.
> > I have 3 servers for my openstack, built with Kolla-ansible, I'm in Victoria version.
> > I had simply put the 3 servers in the [compute] part of the multinode file, at first it worked, but for some time all the VMs are placed on server 1.
> > 
> > The 3 servers are operational, identical. here are 3 screenshots to show it. (on the images, the instances on servers 2 and 3 are present because it worked correctly, but no more instances are created on these servers now)
> > [cid:17eff2778356f37a4481]
> > [cid:17eff277835e47aa83c2]
> > [cid:17eff2778356f53d34a3]
> > 
> > 
> > I tried to understand how the instances are distributed on the servers, but in my case, I don't understand why none are assigned to the 2nd and 3rd server.
> > How to find the problem? It should be nova-scheduler . Do you have to do anything special? Go see if a parameter has a bad value?
> > 
> > 
> > Thanks in advance if you can help me.
> > 
> > Franck VEDEL
> > 
>