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On Tue, Mar 24, 2015 at 11:57 AM, Deepak Shetty <dpkshetty at gmail.com> wrote:

>
>
> On Tue, Mar 24, 2015 at 10:58 AM, Deepthi Dharwar <
> deepthi at linux.vnet.ibm.com> wrote:
>
>> On 03/23/2015 09:00 PM, Jay Pipes wrote:
>> > On Mon, Mar 23, 2015 at 11:18:28AM +0530, Deepthi Dharwar wrote:
>> >> All the VM information is stored in the instances table.
>> >> This includes all the time related field like scheduled_at,
>> launched_at etc.
>> >>
>> >> After upgrading to Juno, I have noticed that my 'scheduled_at' field
>> >> is not getting reflected at all in the database. I do see my VMs
>> >> being spawned and running just fine. However, the 'launched_at' time
>> >> does get reflected rightly.
>> >>
>> >>
>> >> MariaDB [nova]> select created_at, deleted_at, host,scheduled_at,
>> launched_at from instances;
>> >>
>> +---------------------+---------------------+-----------------------+--------------+---------------------+
>> >> | created_at          | deleted_at          | host                  |
>> scheduled_at | launched_at         |
>> >>
>> +---------------------+---------------------+-----------------------+--------------+---------------------+
>> >> | 2015-03-09 20:00:41 | 2015-03-10 17:12:11 | localhost             |
>> NULL         | 2015-03-09 20:01:30 |
>> >> | 2015-03-11 05:53:13 | NULL                | localhost
>>   | NULL         | 2015-03-18 19:48:12 |
>> >>
>> >>
>> >> Can anyone let me know if this is a genuine issue or have there been
>> >> a recent change in regard to updating this field ?
>> >>
>> >> I am basically trying to find as to how long a particular VM is
>> running on a given host.
>> >> I was using the current time - scheduled time for the same.
>> >> Is there a better way to get this value ?
>> >
>> > Use current_time - launched_at.
>>
>> 'launched_at' will give me the time a particular VM came into being.
>> In a scenario where the VM was launched on host H1, later migrated on to
>> a different host H2, 'launched_at' will not give the time the VM
>> has been running on host H2, where as 'scheduled_at' would have
>> addressed this issue or will it ?
>>
>
> Per the code , patch @ https://review.openstack.org/#/c/143725/2 removed
> scheduled_at
> since the function was no longer used. Googling i couldn't find more info
> on the history behind
> why these 2 fields were there to begin with.
>
> I am _not_ nova expert, but iiuc, a VM is scheduled
> once and changing the host as part of migration isn't scheduling, but i
> could be wrong too.
>
> Since your requirement is to find the time a VM lived on a host, as long
> as launched_at is updated
> post migration, it should suffice i feel ?
>

FWIW, In nova/compute/manager.py line 4036 is where migration ends and line
4042 is where
the launched_at is updated, post migration.

HTH

thanx,
deepak
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