Re: [Engine-devel] Gluster Volume asynchronous tasks

On 08/21/2013 12:46 AM, Sahina Bose wrote: > > On 08/20/2013 04:00 AM, Itamar Heim wrote: >> On 08/12/2013 06:09 AM, Sahina Bose wrote: >>> >>> On 08/12/2013 03:28 PM, Yair Zaslavsky wrote: >>>> >>>> ----- Original Message ----- >>>>> From: "Sahina Bose" <sabose(a)redhat.com&gt; >>>>> To: "Eli Mesika" <emesika(a)redhat.com&gt; >>>>> Cc: "engine-devel" <engine-devel(a)ovirt.org&gt;, arch(a)ovirt.org >>>>> Sent: Monday, August 12, 2013 11:51:15 AM >>>>> Subject: Re: [Engine-devel] Gluster Volume asynchronous tasks >>>>> >>>>> >>>>> On 08/12/2013 01:21 PM, Eli Mesika wrote: >>>>>> ----- Original Message ----- >>>>>>> From: "Sahina Bose" <sabose(a)redhat.com&gt; >>>>>>> To: "engine-devel" <engine-devel(a)ovirt.org&gt;, arch(a)ovirt.org, >>>>>>> "Michael >>>>>>> Pasternak" <mpastern(a)redhat.com&gt; >>>>>>> Sent: Monday, August 12, 2013 8:41:55 AM >>>>>>> Subject: [Engine-devel] Gluster Volume asynchronous tasks >>>>>>> >>>>>>> Hi all, >>>>>>> >>>>>>> We are working on a feature to add support to start and monitor >>>>>>> gluster >>>>>>> volume asynchronous tasks (like rebalancing a gluster volume, >>>>>>> removing >>>>>>> brick from volume ) from the oVirt engine. >>>>>>> >>>>>>> The operations can be started from the Volumes tab or the Bricks >>>>>>> sub-tab >>>>>>> using the Rebalance, Remove options. >>>>>>> These are long running operations which can be monitored using a >>>>>>> task id >>>>>>> returned from Gluster. We are planning to add the monitoring in >>>>>>> the >>>>>>> existing Task sub tab >>>>>>> >>>>>>> The feature description and User flows are at >>>>>>> http://www.ovirt.org/Features/Gluster_Volume_Asynchronous_Tasks_Management >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> The detailed design (including REST API design) is at >>>>>>> http://www.ovirt.org/Features/Detailed_Gluster_Volume_Asynchronous_Tasks_.... >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>>> I would really appreciate if you could review and provide your >>>>>>> valuable >>>>>>> feedback. >>>>>> I Sahina >>>>>> Why not using 6the External Tasks feature introduced for 3.3 for >>>>>> those >>>>>> Gluster tasks ??? >>>>>> http://www.ovirt.org/Features/Design/DetailedExternalTasks >>>>> Hi Eli, >>>>> >>>>> We still want to be able to start and stop these operations from the >>>>> engine. >>>>> So, when a user wants to say, rebalance a volume, they would go >>>>> select >>>>> the volume and click on Rebalance Start. >>>>> This would then call the BLL command to start rebalance which will >>>>> invoke the corresponding vdsm verb to start the rebalance on the >>>>> volume. >>>>> This is the same as existing flow for other commands. The only >>>>> difference is the vdsm verb will return the task id from gluster, >>>>> for >>>>> the rebalance operation that was started. And we will monitor the >>>>> progress of the task using the gluster task id (by calling a gluster >>>>> command) >>>>> >>>>> I'm not sure how ExternalTasks would fit in here? I was thinking of >>>>> using ExternalTask support for adding Job/Steps to engine when the >>>>> operation is started outside of engine, that is, from Gluster CLI. >>>>> Please correct me if I'm missing something. >>>> Does this mean that from Gluster CLI you will not try and invoke the >>>> rebalance command ? >>>> (I mean, I should either use Gluster CLI or Engine's REST API?) >>> Rebalance volume command could be invoked in any of the following >>> ways: >>> 1. From the console UI (clicking on Rebalance as shown in >>> http://www.ovirt.org/Features/Gluster_Volume_Asynchronous_Tasks_Managemen...) >>> >>> >>> >>> 2. Using REST API >>> 3. Outside of engine, from Gluster CLI - In such cases, the engine >>> should detect that a user has triggered rebalance operation outside >>> the >>> engine, and allow the user to monitor progress of this from the >>> engine. >>> This is where, we need support to add a Job for an operation that was >>> started externally, so that it can be seen in the Tasks tab. >> >> and still, it should be considered an internal task, since the engine >> is managing it / detected it. >> > > Itamar, yes, you are right. This would need to be treated as an internal > task as the engine needs to be able to stop it and also monitor it. We > would probably need a similar mechanism as external task injection, to > add a Job for the task started from gluster CLI. > > even if it was started from CLI, wouldn't it be better if engine detected it, and still treated it as an internal task, allowing to cancel it, etc.?