Open Stack

> -----Original Message-----
> From: Jay Pipes [mailto:jaypipes at gmail.com]
> Sent: Tuesday, May 06, 2014 10:44 AM
> To: openstack-dev at lists.openstack.org
> Subject: Re: [openstack-dev] [nova] Question about addit log in
> nova-compute.log
> 
> On 05/06/2014 01:37 PM, Jiang, Yunhong wrote:
> >> -----Original Message-----
> >> From: Jay Pipes [mailto:jaypipes at gmail.com]
> >> Sent: Monday, May 05, 2014 6:19 PM
> >> To: openstack-dev at lists.openstack.org
> >> Subject: Re: [openstack-dev] [nova] Question about addit log in
> >> nova-compute.log
> >>
> >> On 05/05/2014 04:19 PM, Jiang, Yunhong wrote:
> >>>> -----Original Message-----
> >>>> From: Jay Pipes [mailto:jaypipes at gmail.com]
> >>>> Sent: Monday, May 05, 2014 9:50 AM
> >>>> To: openstack-dev at lists.openstack.org
> >>>> Subject: Re: [openstack-dev] [nova] Question about addit log in
> >>>> nova-compute.log
> >>>>
> >>>> On 05/04/2014 11:09 PM, Chen CH Ji wrote:
> >>>>> Hi
> >>>>>                   I saw in my compute.log has following logs
> which
> >> looks
> >>>>> to me strange at first, Free resource is negative make me confused
> >> and I
> >>>>> take a look at the existing code
> >>>>>                   looks to me the logic is correct and calculation
> >> doesn't
> >>>>> have problem ,but the output 'Free' is confusing
> >>>>>
> >>>>>                   Is this on purpose or might need to be
> enhanced?
> >>>>>
> >>>>> 2014-05-05 10:51:33.732 4992 AUDIT
> >> nova.compute.resource_tracker
> >>>> [-]
> >>>>> Free ram (MB): -1559
> >>>>> 2014-05-05 10:51:33.732 4992 AUDIT
> >> nova.compute.resource_tracker
> >>>> [-]
> >>>>> Free disk (GB): 29
> >>>>> 2014-05-05 10:51:33.732 4992 AUDIT
> >> nova.compute.resource_tracker
> >>>> [-]
> >>>>> Free VCPUS: -3
> >>>>
> >>>> Hi Kevin,
> >>>>
> >>>> I think changing "free" to "available" might make things a little more
> >>>> clear. In the above case, it may be that your compute worker has
> both
> >>>> CPU and RAM overcommit enabled.
> >>>>
> >>>> Best,
> >>>> -jay
> >>>
> >>> HI, Jay,
> >>> 	I don't think change 'free' to 'available' will make it clearer.
> >>> 	IMHO, the calculation of the 'free' is bogus. When report the
> status in
> >> the periodic task, the resource tracker has no idea of the over-commit
> >> ration at all, thus it simply subtract the total RAM number assigned to
> >> instances from the RAM number provided by hypervisor w/o
> considering
> >> the over-commitment at all. So this number really have meaningless.
> >>
> >> Agreed that in it's current state, it's meaningless. But... that said,
> >> the numbers *could* be used to show oversubscription percentage,
> and
> >> you
> >> don't need to know the max overcommit ratio in order to calculate that
> >> with the numbers already known.
> >
> > I don't think user can use these number to calculate the 'available'. User
> has to know the max overcommit ratio to know the 'available'. Also, it's
> really ironic to provide some meaningless information and have the user
> to calculate to get meaningful.
> >
> > This is related to https://bugs.launchpad.net/nova/+bug/1300775 . I
> think it will be better if we can have the resource tracker to knows about
> the ratio.
> 
> Sorry, you misunderstood me... I was referring to the resource tracker
> above, not a regular user. The resource tracker already knows the total
> amount of physical resources available on each compute node, and it
> knows the resource usage reported by each compute node. Therefore,
> the
> resource tracker already has all the information it needs to understand
> the *actual* overcommit ratio of CPU and memory on each compute
> node,
> regardless of the settings of the *maximum* overcommit ratio on a
> compute node (which is in each compute node's nova.conf).
> 
> Hope that makes things a bit clearer! Sorry for the confusion :)

Aha, the 'actual' and 'maximum' makes it quite clear now , thanks for clarification.

--jyh
> 
> Best,
> -jay
> 
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