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Re: KVM Max Guests Limit


For me, that seems some restrictions in paid productions. “you are client
type X, then you can start only Y VMs”, and this has been a legacy around
our code base.  We could very much remove this limit (on instance numbers);
I expect operators to know what they are doing, and to monitor closely the
platforms/systems they run. The management of other resources such as RAM,
CPU, and others, I still consider them necessary though.

On Fri, Nov 9, 2018 at 10:03 AM Wido den Hollander <wido@xxxxxxxxx> wrote:

>
>
> On 11/9/18 12:56 PM, Andrija Panic wrote:
> > afaik not - but I did run once or twice intom perhaps looselym connected
> > issue - ACS reports 100% of host RAM (makes sense) asavailable for VM
> > deployment to ACS - so in 1-2 cases I did run into out of memory killer,
> > crashing my VMs.
> >
> > It would be great to have some amount of "reserve RAM" for host OS - or
> > simply have PER HOST RAM disableTreshold setting, similar to cluster
> level
> > "cluster.memory.allocated.capacity.disablethreshold", just on host
> level...
> >
>
>
> You can do that already, in agent.properties you can set reserved memory.
>
> But I doubt indeed that we need such a limit in ACS at all, why do we
> need to limit the amount of Instances on a hypervisor?
>
> Or at least set it to a very high number by default.
>
> Wido
>
> > On Fri, 9 Nov 2018 at 12:03, Rafael Weingärtner <
> rafaelweingartner@xxxxxxxxx>
> > wrote:
> >
> >> Do we need these logical constraints in ACS at all?
> >>
> >> On Fri, Nov 9, 2018 at 6:57 AM Wido den Hollander <wido@xxxxxxxxx>
> wrote:
> >>
> >>>
> >>>
> >>> On 11/8/18 11:20 PM, Simon Weller wrote:
> >>>> I think these is legacy and a guess back in the day. It was 50 at one
> >>> point and it was lifted higher a few releases. ago.
> >>>>
> >>>
> >>> I see. I'm about to do a test with a bunch of 128GB hypervisors and
> >>> spawning a lot of 128M VMs. Trying to see where the limit might be and
> >>> also stress the VR a bit by loading a lot of DHCP entries.
> >>>
> >>> Wido
> >>>
> >>>>
> >>>>
> >>>>
> >>>> ________________________________
> >>>> From: Ivan Kudryavtsev <kudryavtsev_ia@xxxxxxxxx>
> >>>> Sent: Thursday, November 8, 2018 3:58 PM
> >>>> To: dev
> >>>> Subject: Re: KVM Max Guests Limit
> >>>>
> >>>> Hi all, +1 for higher numbers.
> >>>>
> >>>> чт, 8 нояб. 2018 г. в 16:32, Wido den Hollander <wido@xxxxxxxxx>:
> >>>>
> >>>>> Hi,
> >>>>>
> >>>>> I see that for KVM we set the limit to 144 guests by default, can
> >>>>> anybody tell me why we have this limit set to 144?
> >>>>>
> >>>>> Searching a bit I found this:
> >>>>> https://access.redhat.com/articles/rhel-kvm-limits
> >>>>>
> >>>>> "This guest limit does not apply to Red Hat Enterprise Linux with
> >>>>> Unlimited Guests. There is no guest limit for Red Hat Enterprise
> >>>>> Virtualization"
> >>>>>
> >>>>> There is always a limit somewhere, but why do we set it to 144?
> >>>>>
> >>>>> I would personally vote for increasing this to 500 or something so
> >> that
> >>>>> users don't run into it that easily.
> >>>>>
> >>>>> Also, the log line is printed in DEBUG mode only when a host reaches
> >>>>> this limit, so I created a PR to set this to INFO:
> >>>>> https://github.com/apache/cloudstack/pull/3013
> >>>>>
> >>>>> Any input?
> >>>>>
> >>>>> Wido
> >>>>>
> >>>>
> >>>>
> >>>> --
> >>>> With best regards, Ivan Kudryavtsev
> >>>> Bitworks LLC
> >>>> Cell RU: +7-923-414-1515
> >>>> Cell USA: +1-201-257-1512
> >>>> WWW: http://bitworks.software/ <http://bw-sw.com/>
> >>>>
> >>>
> >>
> >>
> >> --
> >> Rafael Weingärtner
> >>
> >
> >
>


-- 
Rafael Weingärtner