+1 for Vlad's suggestion to allow wildcard in specifying operator anti-affinity or exclusive allocation.
On Thu, Jan 21, 2016 at 4:49 AM, Pramod Immaneni <[email protected]> wrote: > Once released won't the containers be available again in the pool. This > would only be optional and not mandatory. > > Thanks > > On Tue, Jan 19, 2016 at 2:02 PM, Thomas Weise <[email protected]> > wrote: > > > How about also supporting a minor variation of it as an option > > > where it greedily gets the total number of containers and discards ones > > it > > > can't use and repeats the process for the remaining till everything has > > > been allocated. > > > > > > This is problematic as with resource preemption these containers will be > > potentially taken away from other applications and then thrown away. > > > > > > > > > > > Also does it make sense to support anti-cluster affinity? > > > > > > Thanks > > > > > > On Tue, Jan 19, 2016 at 1:21 PM, Isha Arkatkar <[email protected]> > > > wrote: > > > > > > > Hi all, > > > > > > > > We want add support for Anti-affinity in Apex to allow > applications > > to > > > > launch specific physical operators on different nodes(APEXCORE-10 > > > > <https://issues.apache.org/jira/browse/APEXCORE-10>). Want to > request > > > your > > > > suggestions/ideas for the same! > > > > > > > > The reasons for using anti-affinity in operators could be: to > ensure > > > > reliability, for performance reasons (such as application may not > want > > 2 > > > > i/o intensive operators to land on the same node to improve > > performance) > > > or > > > > for some application specific constraints(for example, 2 partitions > > > cannot > > > > be run on the same node since they use same port number). This is the > > > > general rationale for adding Anti-affinity support. > > > > > > > > Since, Yarn does not support anti-affinity yet (YARN-1042 > > > > <https://issues.apache.org/jira/browse/YARN-1042>), we need to > > implement > > > > the logic in AM. Wanted to get your views on following aspects for > this > > > > implementation: > > > > > > > > *1. How to specify anti-affinity for physical operators/partitions in > > > > application:* > > > > One way for this is to have an attribute for setting > anti-affinity > > at > > > > the logical operator context. And an operator can set this attribute > > with > > > > list of operator names which should not be collocated. > > > > Consider dag with 3 operators: > > > > TestOperator o1 = dag.addOperator("O1", new TestOperator()); > > > > TestOperator o2 = dag.addOperator("O2", new TestOperator()); > > > > TestOperator o3 = dag.addOperator("O3", new TestOperator()); > > > > > > > > To set anti-affinity for O1 operator: > > > > dag.setAttribute(o1, OperatorContext.ANTI_AFFINITY, new > > > > ArrayList<String>(Arrays.asList("O2", "O3"))); > > > > This would mean O1 should not be allocated on nodes containing > > > > operators O2 and O3. This applies to all allocated partitions of O1, > > O2, > > > > O3. > > > > > > > > Also, if same operator name is part of anti-affinity list, it > means > > > > partitions of the operator should not be allocated on the same node. > > > > example: > > > > dag.setAttribute(o2, OperatorContext.ANTI_AFFINITY, new > > > > ArrayList<String>(Arrays.asList("O2"))); > > > > This indicates anti-affinity between all partitions of O2. i.e. > all > > > > partitions of O2 should be launched on different nodes. > > > > > > > > Based on the anti-affinity attribute specified for logical > operator, > > > > during physical plan creation, we can add this list to each > > PTContainer. > > > > This in turn will be available for Stram for sending container > requests > > > > accordingly. > > > > > > > > Please suggest if there is a better way to express this intent. > > > > > > > > *2. How to implement anti-affinity in AM* > > > > There are 2 ways we can implement this: > > > > * a. Blacklisting of nodes: *We can group the physical container > > > requests > > > > based on anti-affinity requirements and send allocation requests for > > > > containers in groups. After first group is done, blacklist the nodes > > > before > > > > sending second group of container requests. This will ensure that the > > > > containers with anti-affinity requirements will be allocated on > > > different > > > > nodes. > > > > * b. Node specific container request: *Explore and create a map of > > > nodes > > > > present in the cluster and send allocation request for container on a > > > > specific node, honoring anti-affinity. There are couple of open Yarn > > > Jiras > > > > for node specific container requests: YARN-1412 > > > > <https://issues.apache.org/jira/browse/YARN-1412>, YARN-2027 > > > > <https://issues.apache.org/jira/browse/YARN-2027>. So, need to check > > if > > > > this is a plausible approach. > > > > > > > > *3. Strict Vs Relaxed anti-affinity* > > > > Depending on cluster resources availability, it may not be possible > > to > > > > honor all anti-affinity requirements specified. > > > > *Strict Anti-affinity:* AM will keep trying to allocate containers as > > per > > > > anti-affinity requirements indefinitely. This behavior will be > similar > > to > > > > how an application shows in ACCEPTED state, till resources are > > available > > > to > > > > launch in cluster. > > > > *Relaxed Anti-affinity:* AM will drop the anti-affinity constraint > > after > > > a > > > > certain timeout. > > > > > > > > We need a way to set this attribute through application. (Either in > > > > operator context or in DAGContext for application wide setting.) > > > > > > > > *4. How do we unit test this feature* > > > > We could use Mockito for mocking Yarn behaviors and test only AM > > > > implementation, since it may not be easy to simulate some scenarios > > > > manually in cluster. Please suggest if there are better ways to test > > > this. > > > > > > > > Please suggest improvements or any other ideas on all of the above. > > > > > > > > Thanks! > > > > Isha > > > > > > > > P.S. Sorry for long email. Please let me know if I should start > > separate > > > > threads for any of the above points. > > > > > > > > > >
