Re: [Engine-devel] Gluster Volume asynchronous tasks

From: "Sahina Bose" <sabose(a)redhat.com&gt; To: "Itamar Heim" <iheim(a)redhat.com&gt; Cc: "engine-devel" <engine-devel(a)ovirt.org&gt;, arch(a)ovirt.org Sent: Wednesday, August 21, 2013 2:19:51 PM Subject: Re: [Engine-devel] Gluster Volume asynchronous tasks On 08/21/2013 03:54 PM, Itamar Heim wrote: > 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.? Yes, but I need to add a Job for this internal task, so that it can be monitored in the Tasks pane. Any idea if I can use any existing framework to do it? I was thinking I would use ExecutionHandler.createJob to do this (similar to what's done in AddExternalJobCommand)

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