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Re: KVM Max Guests Limit


Please LGTM if OK... https://github.com/apache/cloudstack/pull/3016

On Fri, 9 Nov 2018 at 14:20, Andrija Panic <andrija.panic@xxxxxxxxx> wrote:

> THx Wido, let me add this to agent.properties template on master, since
> it's missing, I have no idea where you got it from (perhaps from code that
> uses it)....
>
> thx
>
> On Fri, 9 Nov 2018 at 13:35, Wido den Hollander <wido@xxxxxxxxx> wrote:
>
>>
>>
>> On 11/9/18 1:33 PM, Andrija Panic wrote:
>> > Thanks Wido - though I don't seem to be able to find any related setting
>> > (there is host.overcommit.mem.mb but that is not it - unless you can
>> > define negative value to it )  ?
>> >
>> https://github.com/apache/cloudstack/blob/master/agent/conf/agent.properties
>> >
>>
>> host.reserved.mem.mb=32768
>>
>> That one should be the setting you might want to look at.
>>
>> In this case 32G is reserved and not available to CS.
>>
>> Wido
>>
>> >
>> > thx
>> >
>> > On Fri, 9 Nov 2018 at 13:03, Wido den Hollander <wido@xxxxxxxxx
>> > <mailto: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 <mailto: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
>> >     <mailto: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
>> >     <mailto: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
>> >     <mailto: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
>> >     >>
>> >     >
>> >     >
>> >
>> >
>> >
>> > --
>> >
>> > Andrija Panić
>>
>
>
> --
>
> Andrija Panić
>


-- 

Andrija Panić