VCL computer settings: RAM, processors, and speed

[Mike Haudenschild <mi...@longsight.com>]

Good morning --

I have two questions regarding computer settings in VCL -- the "RAM," "No.
Processors," and "Processors Speed (MHz)" settings when creating computers,
or editing computer information from the Manage Computers tab.

Note that I'm using VCL exclusively with ESXi 4.1, manually installed (no
xCAT).

   1. Am I correct that these settings are irrelevant for my VMWare host
   computer because ESXi was manually installed (i.e. not provisioned via
   xCAT)?
   2. I've watched the VCL bootcamp videos from NCSU this past summer, and
   there was a comment that these settings apply only to virtual machines --
   specifically, to match requested images up with available VMs.  However,
   end-user reservations are getting hardware based upon what was configured
   for the original image, not what I've subsequently specified when adding
   individual VM "computers" or "slots."  For example, the base image was
   created with a 2GHz processor and 512 MB RAM.  When a reservation is made
   using a VM that I've set as having only 256MB RAM and a 1GHZ processor,
   those settings seem to be ignored -- the original hardware settings from
   the image (2GHz, 512MB RAM) are assigned to the VM slot.

Thanks to everyone on the list -- you've all been so helpful as I'm getting
to know VCL.

Regards,
Mike

--
*Mike Haudenschild*
Education Systems Manager
Longsight Group
(740) 599-5005 x809
mike@longsight.com
www.longsight.com

Re: VCL computer settings: RAM, processors, and speed

[Mike Haudenschild <mi...@longsight.com>]

Hi Andy --

I have one XP image (created w/ 512MB RAM).  I created two VM "computers,"
one with only 256MB RAM.  Two reservations of the image started on each of
the two VMs -- but VCL created two identical 512MB VMs on ESXi, and started
the image on both.

If there's a hard-coded minimum RAM of 512MB, that would explain what I'm
seeing.  Does that sound correct?

If I create a new base image with 1024MB RAM, will VCL deploy it on a VM
"computer" with only 512MB?

Thanks,
Mike



> 1) By the scheduler to locate a computer that meets the requirements
> set in the image profile.  This is the same for VMs and bare-metal
> computers.  If your VM is set to 256 MB and your image is set to 512
> MB, reservations for that image shouldn't be scheduled on that VM.  Is
> this what you're seeing?  If so then there's a problem with the
> scheduling code.
>


> 2) By the provisioning module to construct a VM.  The RAM and CPU
> values for the image are normally used.  If your image is set to 1 GB
> RAM and your computer is set to 2 GB, the VM will have 1 GB.
>
> There are a few caveats.  There is a hard-coded minimum RAM value of
> 512 MB.  This is done to prevent unusable VMs from being created if
> the image profile RAM setting is set to 0 or a very low value.  If
> your computer is set to 1 GB and your image is set to 256 MB, the VM
> will be assigned 512 MB.  There are other RAM minimums higher than 512
> MB depending on the OS of the image being loaded.  I don't recall all
> of them off hand but for example I believe 32-bit Windows 7 is 1 GB,
> etc.

Re: VCL computer settings: RAM, processors, and speed

[Andy Kurth <an...@ncsu.edu>]

On Tue, Dec 27, 2011 at 11:25 AM, Mike Haudenschild <mi...@longsight.com> wrote:
> Good morning --
>
> I have two questions regarding computer settings in VCL -- the "RAM," "No.
> Processors," and "Processors Speed (MHz)" settings when creating computers,
> or editing computer information from the Manage Computers tab.
>
> Note that I'm using VCL exclusively with ESXi 4.1, manually installed (no
> xCAT).
>
>   1. Am I correct that these settings are irrelevant for my VMWare host
>   computer because ESXi was manually installed (i.e. not provisioned via
>   xCAT)?

Yes.  The VM host hardware values aren't currently used.  They will be
used at some point in the future to determine host
capacity/utilization in order to improve the scheduling of
reservations.  It's not important to set these accurately because the
code will automatically retrieve the values from the host and update
the database.

>   2. I've watched the VCL bootcamp videos from NCSU this past summer, and
>   there was a comment that these settings apply only to virtual machines --
>   specifically, to match requested images up with available VMs.  However,
>   end-user reservations are getting hardware based upon what was configured
>   for the original image, not what I've subsequently specified when adding
>   individual VM "computers" or "slots."  For example, the base image was
>   created with a 2GHz processor and 512 MB RAM.  When a reservation is made
>   using a VM that I've set as having only 256MB RAM and a 1GHZ processor,
>   those settings seem to be ignored -- the original hardware settings from
>   the image (2GHz, 512MB RAM) are assigned to the VM slot.

The VM hardware settings are used in 2 ways:

1) By the scheduler to locate a computer that meets the requirements
set in the image profile.  This is the same for VMs and bare-metal
computers.  If your VM is set to 256 MB and your image is set to 512
MB, reservations for that image shouldn't be scheduled on that VM.  Is
this what you're seeing?  If so then there's a problem with the
scheduling code.

2) By the provisioning module to construct a VM.  The RAM and CPU
values for the image are normally used.  If your image is set to 1 GB
RAM and your computer is set to 2 GB, the VM will have 1 GB.

There are a few caveats.  There is a hard-coded minimum RAM value of
512 MB.  This is done to prevent unusable VMs from being created if
the image profile RAM setting is set to 0 or a very low value.  If
your computer is set to 1 GB and your image is set to 256 MB, the VM
will be assigned 512 MB.  There are other RAM minimums higher than 512
MB depending on the OS of the image being loaded.  I don't recall all
of them off hand but for example I believe 32-bit Windows 7 is 1 GB,
etc.

-Andy

> Thanks to everyone on the list -- you've all been so helpful as I'm getting
> to know VCL.
>
> Regards,
> Mike
>
> --
> *Mike Haudenschild*
> Education Systems Manager
> Longsight Group
> (740) 599-5005 x809
> mike@longsight.com
> www.longsight.com