Thanks for the clarification Subru. I am in favor of moving forward.
Sangjin On Thu, Jun 22, 2017 at 6:21 PM, Karthik Shashank Kambatla < [email protected]> wrote: > Given RTC and the amount of production testing this feature has received, I > am totally in favor of this merge. > > > > On Tue, Jun 20, 2017 at 4:28 PM, Subru Krishnan <[email protected]> wrote: > > > Hi all, > > > > We would like to open a discussion on merging the YARN Federation > > (YARN-2915) [1] feature to trunk. We have been developing the feature > in a > > feature branch (YARN-2915 [2]) for a while, and we are reasonably > confident > > that the state of the feature meets the criteria to be merged onto trunk. > > > > *Key Ideas*: > > > > YARN’s centralized design allows strict enforcement of scheduling > > invariants and effective resource sharing, but becomes a scalability > > bottleneck (in number of jobs and nodes) well before reaching the scale > of > > our clusters (e.g., 20k-50k nodes). > > > > > > To address these limitations, we developed a scale-out, federation-based > > solution (YARN-2915). Our architecture scales near-linearly to datacenter > > sized clusters, by partitioning nodes across multiple sub-clusters (each > > running a YARN cluster of few thousands nodes). Applications can span > > multiple sub-clusters *transparently (i.e. no code change or > recompilation > > of existing apps)*, thanks to a layer of indirection that negotiates with > > multiple sub-clusters' Resource Managers on behalf of the application. > > > > > > This design is structurally scalable, as it bounds the number of nodes > each > > RM is responsible for. Appropriate policies ensure that the majority of > > applications reside within a single sub-cluster, thus further controlling > > the load on each RM. This provides near linear scale-out by simply adding > > more sub-clusters. The same mechanism enables pooling of resources from > > clusters owned and operated by different teams. > > > > Status: > > > > - The version we would like to merge to trunk is termed "MVP" (minimal > > viable product). The feature will have a complete end-to-end > application > > execution flow with the ability to span a single application across > > multiple YARN (sub) clusters. > > - There were 50+ sub-tasks that were that were completed as part of > this > > effort. Every patch has been reviewed and +1ed by a committer. Thanks > to > > Jian, Wangda, Karthik, Vinod, Varun & Arun for the thorough reviews! > > - Federation is designed to be built around YARN and consequently has > > minimal code changes to core YARN. The relevant JIRAs that modify > > existing > > YARN code base are YARN-3671 [7] & YARN-3673 [8]. We also paid close > > attention to ensure that if federation is disabled there is zero > impact > > to > > existing functionality (disabled by default). > > - We found a few bugs as we went along which we fixed directly > upstream > > in trunk and/or branch-2. > > - We have continuously rebasing the feature branch [2] so the merge > > should be a straightforward cherry-pick. > > - The current version has been rather thoroughly tested and is > currently > > deployed in a *10,000+ node federated YARN cluster that's running > > upwards of 50k jobs daily with a reliability of 99.9%*. > > - We have few ideas for follow-up extensions/improvements which are > > tracked in the umbrella JIRA YARN-5597[3]. > > > > > > Documentation: > > > > - Quick start guide (maven site) - YARN-6484[4]. > > - Overall design doc[5] and the slide-deck [6] we used for our talk at > > Hadoop Summit 2016 is available in the umbrella jira - YARN-2915. > > > > > > Credits: > > > > This is a group effort that could have not been possible without the > ideas > > and hard work of many other folks and we would like to specifically call > > out Giovanni, Botong & Ellen for their invaluable contributions. Also big > > thanks to the many folks in community (Sriram, Kishore, Sarvesh, Jian, > > Wangda, Karthik, Vinod, Varun, Inigo, Vrushali, Sangjin, Joep, Rohith and > > many more) that helped us shape our ideas and code with very insightful > > feedback and comments. > > > > We plan to start the merge vote in the next week or so. The branch is > close > > to complete (~5 patches before one can kick the tires on a running > > deployment). Please look through the branch; feedback is welcome. Thanks! > > > > Cheers, > > Subru & Carlo > > > > [1] YARN-2915: https://issues.apache.org/jira/browse/YARN-2915 > > [2] https://github.com/apache/hadoop/tree/YARN-2915 > > [3] YARN-5597: https://issues.apache.org/jira/browse/YARN-5597 > > [4] YARN-6484: https://issues.apache.org/jira/browse/YARN-6484 > > [5] https://issues.apache.org/jira/secure/attachment/12733292/ > > Yarn_federation_design_v1.pdf > > [6] https://issues.apache.org/jira/secure/attachment/1281922 > > 9/YARN-Federation-Hadoop-Summit_final.pptx > > [7] YARN-3671: https://issues.apache.org/jira/browse/YARN-3671 > > [8] YARN-3673: https://issues.apache.org/jira/browse/YARN-3673 > > >
