[one-users] Resource Overcommit / Provisioning Limitations

[Carlos Martín Sánchez]

Hi,

On Sun, Apr 28, 2013 at 12:18 AM, Jon <three18ti at gmail.com> wrote:

> Hello All,
>
> I'm only able to provision resources up to 750 / 800 CPU and 7GB / 7.8GB.
> VMs provisioned after this limit has been reached causes the VMs to stay
> in "pend" status until vms are turned off or destroyed.
>

The scheduler will reserve some memory for the hypervisor, this can be
configured with the HYPERVISOR_MEM attribute in sched.conf [1].



>   Even though 7GB has been provisioned, I'm hardly using 2G.
>
> >> HOST SHARES
>
> >> TOTAL MEM             : 7.8G
> >> USED MEM (REAL)       : 1.9G
> >> USED MEM (ALLOCATED)  : 7G
> >> TOTAL CPU             : 800
> >> USED CPU (REAL)       : 44
> >> USED CPU (ALLOCATED)  : 750
> >> RUNNING VMS           : 10
>
> How can I configure OpenNebula to allow overcommit of resources?
>
>
Currently there is no way to do Memory over-commitment, but you can do cpu
over-commitment with the CPU & VCPU attributes. For example, if you need a
VM with 2 Virtual CPUs, you don't have to reserve 2 of the Host CPUs; you
could request only 0.25:

CPU = 0.25
VCPU = 2

If you are using 4.0, you can use the onevm resize command [2] on your
existing VMs.


> I see in the host template, there are free/totalmem and free/totalcpu
> parameters:
>
> >> FREECPU="756.0"
> >> FREEMEMORY="6152516"
> >> TOTALCPU="800"
> >> TOTALMEMORY="8169164"
>
> I can edit these in SunStone, but it doesn't seem to have an effect.  As
> they are monitoring attributes, I'm not sure I'm looking in the right place.
>
>
The host template holds the information returned by the drivers. You can
edit it to add custom attributes, but they will not be understood by
OpenNebula as monitoring values. If you want to customize the monitoring
drivers, take a look at this guide [3].

Regards



> Thanks for the advice,
> Jon A
>
> _______________________________________________
> Users mailing list
> Users at lists.opennebula.org
> http://lists.opennebula.org/listinfo.cgi/users-opennebula.org
>
>

[1] http://opennebula.org/documentation:rel4.0:schg
[2] http://opennebula.org/documentation:rel4.0:vm_guide_2#resizing_a_vm
[3] http://opennebula.org/documentation:rel4.0:img#tuning_extending

--
Carlos Martín, MSc
Project Engineer
OpenNebula - The Open-source Solution for Data Center Virtualization
www.OpenNebula.org <http://www.opennebula.org/> | cmartin at opennebula.org |
@OpenNebula <http://twitter.com/opennebula> <cmartin at opennebula.org>
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