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 <xg...@hortonworks.com> 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 <ywsk...@gmail.com> > 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 > > -- > CONFIDENTIALITY NOTICE > NOTICE: This message is intended for the use of the individual or entity to > which it is addressed and may contain information that is confidential, > privileged and exempt from disclosure under applicable law. If the reader > of this message is not the intended recipient, you are hereby notified that > any printing, copying, dissemination, distribution, disclosure or > forwarding of this communication is strictly prohibited. If you have > received this communication in error, please contact the sender immediately > and delete it from your system. Thank You. > -- CONFIDENTIALITY NOTICE NOTICE: This message is intended for the use of the individual or entity to which it is addressed and may contain information that is confidential, privileged and exempt from disclosure under applicable law. If the reader of this message is not the intended recipient, you are hereby notified that any printing, copying, dissemination, distribution, disclosure or forwarding of this communication is strictly prohibited. If you have received this communication in error, please contact the sender immediately and delete it from your system. Thank You.
