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Hadoop >> mail # dev >> question about when do resource matching in YARN


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Re: question about when do resource matching in YARN
I don't believe there is any reason scheduling decisions need to be coupled
with NodeManager heartbeats.  It doesn't sidestep any race conditions
because a NodeManager could die immediately after heartbeating.
On Sat, Sep 21, 2013 at 2:11 AM, Omkar Joshi <[EMAIL PROTECTED]> wrote:

> Hi Wei,
>
> Yes there is a clear lag between AM requesting resource and satisfying NM
> heartbeats (thereby we process the event) are received. Developers in
> project Tez ( http://incubator.apache.org/projects/tez.html ) have done
> some similar stuff. You can check it there. I hope it helps.
>
> Thanks,
> Omkar Joshi
> *Hortonworks Inc.* <http://www.hortonworks.com>
>
>
> On Fri, Sep 20, 2013 at 8:56 AM, Xuan Gong <[EMAIL PROTECTED]> wrote:
>
> > Hey, Wei:
> >       The nodeHeartBeat is used to let RM knows this NM is still alive.
> We
> > only assign containers from alive NM. Another thing is when scheduler
> > receives the nodeHeartBeat, the scheduler will get the container status
> > (such as completed, new launched) from NM, and it can use it to update
> the
> > resource.
> >
> >        You can take a look those source codes, it can help you understand
> > better.
> > 1. NodeStatusUpdaterImpl::startStatusUpdater(). it used to send out the
> > nodeheartbeat
> > 2. ResourceTrackerService::nodeHeartbeat(). This one is used to get
> > heartbeat from NM, and send to RMNodeImpl
> > 3. RMNodeImpl::StatusUpdateWhenHealthyTransition().  Get the heartBeat,
> and
> > do locally update.
> > 4. CapacityScheduler::nodeUpdate(). Processing the heartbeat info, and
> > potentially assign containers.
> >
> > Thanks
> >
> > Xuan
> >
> >
> > On Fri, Sep 20, 2013 at 7:17 AM, wei yan @ Gmail <[EMAIL PROTECTED]>
> > wrote:
> >
> > > Hi, all,
> > >
> > > I have a simple question. Currently in YARN, the resource matching is
> > > triggered by the node manager heartbeat. That is, assignContainers() is
> > > only invoked when a new heartbeat comes in. Why we don't use resource
> > > request triggered mechanism? That is, when AM submits allocateRequest,
> we
> > > do the resource matching and assign containers.
> > >
> > > Does anybody have any idea about this?
> > >
> > > thanks,
> > > Wei
> >
> > --
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NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB