[one-dev] Scheduler decisions regarding storage

[Carlos Martín Sánchez]

Adding to what Rubén said, VirtualMachine::get_requirements will report the
needed storage when we address this issue:
http://dev.opennebula.org/issues/2402

--
Carlos Martín, MSc
Project Engineer
OpenNebula - Flexible Enterprise Cloud Made Simple
www.OpenNebula.org | cmartin at opennebula.org | @OpenNebula
<http://twitter.com/opennebula> <cmartin at opennebula.org>


On Thu, Jun 12, 2014 at 11:56 AM, Ruben S. Montero <rsmontero at opennebula.org
> wrote:

> Hi Stuart
>
> That code, as you suggest in your first email, is actually in the
> scheduler. You are probably interested in VirtualMachineXML class, specially
>
> Computation on the storage needed by the VM[1]:
>   * IT considers the DS and specific mechanisms of the CLONE and LN
> operations (i.e. if the storage needed to CLONE and LN takes space from the
> system_ds or the image ds)
>   * The updated version of the get_requirements function is also in that
> class [2]
>   * Available capacity of the DS is inititalized here [3] (DatastoreXML
> class)
>
> The actual scheduling is do in two-phases:
>
>   * Datastores are filtered based on capacity (using previous functions)
> and requirements [4]
>   * System DS + Host are jointly scheduled later, the DS part is [5]
>
> [1]
> https://github.com/OpenNebula/one/blob/master/src/scheduler/src/pool/VirtualMachineXML.cc#L306
>
> [2]
> https://github.com/OpenNebula/one/blob/master/src/scheduler/src/pool/VirtualMachineXML.cc#L272
>
> [3]
> https://github.com/OpenNebula/one/blob/master/src/scheduler/src/pool/DatastoreXML.cc#L35
>
> [4]
> https://github.com/OpenNebula/one/blob/master/src/scheduler/src/sched/Scheduler.cc#L751
>
> [5]
> https://github.com/OpenNebula/one/blob/master/src/scheduler/src/sched/Scheduler.cc#L1051
>
>
>
> On Sun, Jun 8, 2014 at 10:24 AM, Stuart Longland <stuartl at vrt.com.au>
> wrote:
>
>> On 05/06/14 12:32, Stuart Longland wrote:
>> > What I observe though, is that the disk storage always returns 0.  My
>> > plan was to expand on this by adding an extra parameter (int& cache),
>> > and I'd use whatever code is present to calculate disk requirements to
>> > figure out how much to cache and thus, calculate the cache output.
>>
>> I've gone digging further back into the git repository to see if there
>> was previously code that calculated the disk requirements.
>>
>> It seems not.  The file in question was added back in 2008, "Initial
>> commit of ONE code", and those lines are largely unchanged today
>> according to `git blame`.  So I guess it was a place-holder that never
>> got filled in, perhaps because it hasn't been needed until now.
>>
>> The data needed on the host is going to largely depend on what kind of
>> datastore is being used.  Plain files using SSH for transfer is going to
>> require space for full images on the hosts, whereas datastores using
>> centralised storage won't require any (unless cached).
>>
>> I think it makes sense to have the system work out an estimate for how
>> much storage might be needed on the host to run the VM.  Now it's a
>> question of do I re-use the "disk" parameter, meaning required "local
>> disk on host" including cache, or do I create another variable as I was
>> planning?
>>
>> Regards,
>> --
>> Stuart Longland
>> Systems Engineer
>>      _ ___
>> \  /|_) |                           T: +61 7 3535 9619
>>  \/ | \ |     38b Douglas Street    F: +61 7 3535 9699
>>    SYSTEMS    Milton QLD 4064       http://www.vrt.com.au
>>
>>
>> _______________________________________________
>> Dev mailing list
>> Dev at lists.opennebula.org
>> http://lists.opennebula.org/listinfo.cgi/dev-opennebula.org
>>
>
>
>
> --
> --
> Ruben S. Montero, PhD
> Project co-Lead and Chief Architect
> OpenNebula - Flexible Enterprise Cloud Made Simple
> www.OpenNebula.org | rsmontero at opennebula.org | @OpenNebula
>
> _______________________________________________
> Dev mailing list
> Dev at lists.opennebula.org
> http://lists.opennebula.org/listinfo.cgi/dev-opennebula.org
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.opennebula.org/pipermail/dev-opennebula.org/attachments/20140616/177ecccd/attachment.htm>