Open Stack

On Tue, Nov 5, 2013 at 6:29 AM, Chris Friesen
<chris.friesen at windriver.com> wrote:
> On 11/04/2013 03:49 PM, Solly Ross wrote:
>>
>> So, There's currently an outstanding issue with regards to a Nova
>> shortcut command that creates a volume from an image and then boots
>> from it in one fell swoop.  The gist of the issue is that there is
>> currently a set timeout which can time out before the volume creation
>> has finished (it's designed to time out in case there is an error),
>> in cases where the image download or volume creation takes an
>> extended period of time (e.g. under a Gluster backend for Cinder with
>> certain network conditions).
>>
>> The proposed solution is a modification to the Cinder API to provide
>> more detail on what exactly is going on, so that we could
>> programmatically tune the timeout.  My initial thought is to create a
>> new column in the Volume table called 'status_detail' to provide more
>> detailed information about the current status.  For instance, for the
>> 'downloading' status, we could have 'status_detail' be the completion
>> percentage or JSON containing the total size and the current amount
>> copied.  This way, at each interval we could check to see if the
>> amount copied had changed, and trigger the timeout if it had not,
>> instead of blindly assuming that the operation will complete within a
>> given amount of time.
>>
>> What do people think?  Would there be a better way to do this?
>
>
> The only other option I can think of would be some kind of callback that
> cinder could explicitly call to drive updates and/or notifications of faults
> rather than needing to wait for a timeout.  Possibly a combination of both
> would be best, that way you could add a --poll option to the "create volume
> and boot" CLI command.
>
> I come from the kernel-hacking world and most things there involve
> event-driven callbacks.  Looking at the openstack code I was kind of
> surprised to see hardcoded timeouts and RPC casts with no callbacks to
> indicate completion.
>
> Chris
>
>
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