GitHub user danny0405 opened a pull request:
https://github.com/apache/storm/pull/1874
Strom Rebalance command should support arbitrary component parallelism
For legacy reasons, config TOPOLOGY-TASKS is considered first when
schedule a topology, for a component, if user donât specify TOPOLOGY-TASKS,
storm just override it to be equal of component parallelism hint, and schedule
based on TOPOLOGY-TASKS later on.
This works for the most cases, but not Rebalance command, now, when do
Rebalance, the StormBase :component->executors attribute will be overridden in
Zookeeper is used to partition tasks into executors for components, as we said
above, the TOPOLOGY-TASKS is considered here as the real tasks number for
components, something goes weird here:
If we override a bigger executor numbers for a component when do
rebalance, it just donât work because smaller TOPOLOGY-TASKS [ not changed
since first submitted at all ]is partitioned to bigger number of executors
which read from ZooKeeper overridden by Rebalance command, but for smaller
task, it works fine.
I see that storm support a command like this now: [storm rebalance
topology-name [-w wait-time-secs] [-n new-num-workers] [-e
component=parallelism]*] which indicate that user can override a component
parallelism freely, i think itâs more sensible to support this and it's
meaningless to have a restriction like this.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/danny0405/storm nimbus-promotion
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/storm/pull/1874.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #1874
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commit de4374fd1da4bb0a647f125b91f2f15644c0b2f7
Author: chenyuzhao <chenyuz...@meituan.com>
Date: 2017-01-12T09:21:55Z
refact rebalance to allow modify component parallelism freely
commit 1384071d58020d03c018d9ce98638ee330539300
Author: chenyuzhao <chenyuz...@meituan.com>
Date: 2017-01-13T07:22:09Z
format code
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