yarn.scheduler.capacity.node-locality-delay will help if the app is requesting containers at particular locations, but won't help spread things out evenly otherwise.
The Fair Scheduler attempts an even spread. By default, it only schedules a single container each time it considers a node. Decoupling scheduling from node heartbeats (YARN-1010) makes it so that a high node heartbeat interval doesn't result in this being slow. Now that the Capacity Scheduler has similar capabilities (YARN-1512), it might make sense to introduce a similar limit? -Sandy On Fri, Mar 21, 2014 at 4:42 PM, Vinod Kumar Vavilapalli <[email protected] > wrote: > What's the value for yarn.scheduler.capacity.node-locality-delay? It is -1 > by default in 2.2. > > We fixed the default to be a reasonable 40 (nodes in a rack) in 2.3.0 that > should spread containers a bit. > > Thanks, > +Vinod > > On Mar 21, 2014, at 12:48 PM, Chris Riccomini <[email protected]> > wrote: > > > Hey Guys, > > > > We're running YARN 2.2 with the capacity scheduler. Each NM is running > with 40G of memory capacity. When we request a series containers with 2G of > memory from a single AM, we see the RM assigning them entirely to one NM > until that NM is full, and then moving on to the next, and so on. > Essentially, we have a grid with 20 nodes, and two are completely full, and > the rest are completely empty. This is problematic because our containers > use disk heavily, and are completely saturating the disks on the two nodes, > which slows all of the containers down on these NMs. > > > > 1. Is this expected behavior of the capacity scheduler? What about the > fifo scheduler? > > 2. Is the recommended work around just to increase memory allocation > per-container as a proxy for the disk capacity that's required? Given that > there's no disk-level isolation, and no disk-level resource, I don't see > another way around this. > > > > Cheers, > > Chris > > > -- > 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. >
