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RE: number of cores


I am with KVM.

I am sure it’s the core count preventing me from starting VM’s because when I hack the database to tell it I have 48 cores rather than 24 cores on my hosts, I can then start the VM.

The only thing the logs say is that I can’t create a new VM due to lack of resources. Then it quits saying that when I hack the database. Note that under 4.9.2 (what I reverted back to), Memory is at 49%, CPU is at 41%, Primary Storage is at 5%, and Secondary Storage is at 5%. All other resources aren’t even 1% used (I set up # of vlans, shared network IP’s, etc. fairly large because I expect to grow the cluster in the future).  4.9 doesn’t list CPU cores. Under 4.11.1 those measures were the same.  

I am running KVM under Centos 7. It may be that the KVM allocator works different from the VMware allocator? 

From: Dag Sonstebo
Sent: Monday, November 19, 2018 9:47 AM
To: users@xxxxxxxxxxxxxxxxxxxxx
Subject: Re: number of cores

Andrija - not sure about your 3.4GHz cores - must a be a simplified lookup somewhere making assumptions.

Eric - have just tried your scenario in my 4.11.2RC5 lab (admittedly with VMware, not KVM) - and I can see my core allocation keeps going up, e.g. at the moment it sits at 166% - 10 out of 6 cores used. However it doesn't stop me starting new VMs (only using 30-40% CPU and memory). 
Are you sure it's the core count preventing you from starting VMs? What do the logs say? (Also keep in mind your system VMs are now using more resources that before).

Regards,
Dag Sonstebo
Cloud Architect
ShapeBlue
 

On 19/11/2018, 17:15, "Eric Lee Green" <eric.lee.green@xxxxxxxxx> wrote:

    
    On 11/19/18 03:56, Andrija Panic wrote:
    > Hi Ugo,
    >
    > Why would you want to do this, just curious ?
    >
    > I believe it's not possible, but anyway (at least with KVM, probably same
    > for other hypervisors) it doesn't even makes sense/use, since when
    > deploying a VM, ACS query host free/unused number of MHz (GHz), so it's not
    > even relevant for ACS - number of cores in not relevant in ACS calculations
    > during VM deployment.
    
    
    I think you are misunderstanding the question. I have 72 cores in my 
    cluster. Each of my hosts has 24 cores. With 4.9.2, I can provision 10 
    virtual machines, each of which is programmed with 8 cores, meaning 80 
    cores total. They on average are using only 25% of the CPU available to 
    them (they need to be able to burst) and my compute servers on average 
    are only 40% CPU used so that is not a problem.
    
    When I tried upgrading to 4.11.1,  the dashboard showed a new value "# 
    of CPU Cores" in red and showed that I had more cores provisioned for 
    virtual machines than available in the cluster (80 versus 72 available). 
    Cloudstack would not launch new virtual machines. I shut down two 
    virtual machines, and now I can launch one, but not the second because I 
    would need 80 cores total in my cluster. I cannot launch all 10 virtual 
    machines because I would need 80 cores total. I know this because I 
    tried it. I then used MySQL to tell Cloudstack that each of my hosts has 
    48 cores (144 total), and suddenly I can launch all of my virtual machines.
    
    Is this a bug in 4.11.1? Or is this expected behavior? If expected 
    behavior, is there a way to over-provision "total # of cores used" other 
    than to go into MySQL and tell it that my hosts have more cores than 
    they in fact have? (Note that my service offerings are limited to 8 
    cores max, so there's no way to launch a single VM with more cores than 
    exists on a physical host, since all my hosts have 24 cores).
    
    
    > On Mon, Nov 19, 2018, 11:31 Ugo Vasi <ugo.vasi@xxxxxxxxx.invalid wrote:
    >
    >> Hi all,
    >> in the dashboard of an ACS installation vesion 4.11.1.0 (Ubuntu 16.04
    >> with KVM hypervisor), the new entry "# of CPU Cores" appears.
    >> Is it possible to over-provision like for MHz or storage?
    >>
    >> Thanks
    >>
    >>
    >> --
    >>
    >> *Ugo Vasi* / System Administrator
    >> ugo.vasi@xxxxxxxxx <mailto:ugo.vasi@xxxxxxxxx>
    >>
    >>
    >>
    >>
    >> *Procne S.r.l.*
    >> +39 0432 486 523
    >> via Cotonificio, 45
    >> 33010 Tavagnacco (UD)
    >> www.procne.it <http://www.procne.it/>
    >>
    >>
    >> Le informazioni contenute nella presente comunicazione ed i relativi
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Dag.Sonstebo@xxxxxxxxxxxxx 
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