[jira] [Commented] (AIRFLOW-5763) Run batches of (self-terminating) EMR JobFlows

["ASF GitHub Bot (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/AIRFLOW-5763?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17004521#comment-17004521 ] 

ASF GitHub Bot commented on AIRFLOW-5763:
-----------------------------------------

stale[bot] commented on pull request #6281: Run batches of (self-terminating) EMR JobFlows [AIRFLOW-5763]
URL: https://github.com/apache/airflow/pull/6281
 
 
   
 
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> Run batches of (self-terminating) EMR JobFlows
> ----------------------------------------------
>
>                 Key: AIRFLOW-5763
>                 URL: https://issues.apache.org/jira/browse/AIRFLOW-5763
>             Project: Apache Airflow
>          Issue Type: New Feature
>          Components: aws
>    Affects Versions: 1.10.7
>            Reporter: Throw Away
>            Priority: Trivial
>
> [https://github.com/apache/airflow/pull/6281]
> > Make sure you have checked _all_ steps below.
> > 
> > ### Jira
> > * [x] My PR addresses the following [Airflow Jira](https://issues.apache.org/jira/browse/AIRFLOW/) issues and references them in the PR title. For example, "[AIRFLOW-XXX] My Airflow PR"
> > 
> > * https://issues.apache.org/jira/browse/AIRFLOW-XXX
> > * ~In case you are fixing a typo in the documentation you can prepend your commit with [AIRFLOW-XXX], code changes always need a Jira issue.~
> > * ~In case you are proposing a fundamental code change, you need to create an Airflow Improvement Proposal ([AIP](https://cwiki.apache.org/confluence/display/AIRFLOW/Airflow+Improvements+Proposals)).~
> > * ~In case you are adding a dependency, check if the license complies with the [ASF 3rd Party License Policy](https://www.apache.org/legal/resolved.html#category-x).~
> > 
> > ### Description
> > * [x] Here are some details about my PR, ~including screenshots of any UI changes:~
> > 
> > Run batches of (self-terminating) EMR JobFlows [AIRFLOW-XXX]
> > 
> > ## What is this:
> > This commit introduces an implementation of an `EmrRunJobFlows` operator
> > that allows Airflow to manage the execution of multiple EMR clusters.
> > The clusters are all configured through a Jinja template ahead of time,
> > just like `EmrCreateJobFlowOperator` but are submitted one batch of
> > clusters at a time, allowing for workflows that require sequences of
> > parallel clusters. The operator assumes that all the clusters it
> > manages auto-terminate.
> > 
> > As demonstrated in the unit test, with this operator the following
> > batches of EMR clusters could be set up:
> > 
> > 1. First, cluster1 runs its steps until they all complete and the cluster terminates.
> > 2. Then, cluster2a and cluster2b run their steps in parallel until they both terminate.
> > 3. Finally, cluster3 runs its steps.
> > 
> > Just to be clear, a "batch" of clusters is just a set of clusters that
> > can be run in EMR in parallel.
> > 
> > ## Why use this:
> > 1. The primary appeal of this operator is for submitting one-off tasks
> > to EMR. The most straight-forward way to do this is to set up a DAG
> > consisting of a single `EmrRunJobFlows` operator which derives its
> > `job_flows` value from the DagRun's conf attribute (
> > [`airflow dags trigger --conf`](https://airflow.readthedocs.io/en/latest/cli-ref.html#trigger)). While the actual EMR steps are
> > obfuscated, one small benefit from using this operator over modifying
> > the DAG using the existing EMR operators is that, while the resulting
> > work is dynamic at DagRun-time, the structure of the DAG stays constant
> > between wildly different runs, so we can see the execution history even
> > when a typical DAG would have been modified and lost its history in the
> > Web UI. A more complex implementation of this use-case in a closed-
> > source project was actually the motivation for this PR - my gratitude to
> > @ChengzhiZhao and @TarunChillara for their assistance there.
> > 
> > 1. It can also simplify the retry logic wherever
> > `EmrCreateJobFlowOperator` and `EmrJobFlowSensor` operator pairs are
> > used. In that scenario, the `retry_handler` of an `EmrJobFlowSensor`
> > task would need to run an `airflow clear` on the preceding
> > `EmrCreateJobFlowOperator` task if it detects that the cluster failed,
> > while somehow maintaining the total count of attempts. Using the
> > `EmrJobFlowSensor`, a cluster can be restarted on failure without a
> > custom `retry_handler` - simply by setting `retries > 0`. Please note
> > that, as described in its docstring, the current implementation of
> > `EmrRunJobFlows` limits the retry logic to just this basic use case.
> > This is because we don't expose any information for a `retry_handler` to
> > reason about at this time. This could be improved by pushing step- and
> > cluster- level status information to an XCom, but that is not
> > implemented here at this time because the operator implementation is
> > complex enough as is. If they are to be retried, please make sure that
> > all steps be idempotent.
> > 
> > ### Tests
> > * [x] My PR adds the following unit tests ~**OR** does not need testing for this extremely good reason~:
> > 
> > tests/contrib/sensors/test_emr_run_job_flows.py:
> > 
> > * [test_execute_calls_until_all_clusters_reach_a_terminal_state](https://github.com/apache/airflow/pull/6281/files#diff-19560b77d8ed6911d9103c04c0d67da7R85)
> > * [test_execute_stops_when_cluster_in_batch_fails](https://github.com/apache/airflow/pull/6281/files#diff-19560b77d8ed6911d9103c04c0d67da7R125)
> > * [test_execute_stops_on_cluster_creation_failure](https://github.com/apache/airflow/pull/6281/files#diff-19560b77d8ed6911d9103c04c0d67da7R156)
> > 
> > ### Commits
> > * [x] My commits all reference Jira issues in their subject lines, and I have squashed multiple commits if they address the same issue. In addition, my commits follow the guidelines from "[How to write a good git commit message](http://chris.beams.io/posts/git-commit/)":
> > 
> > 1. Subject is separated from body by a blank line
> > 2. Subject is limited to 50 characters (not including Jira issue reference)
> > 3. Subject does not end with a period
> > 4. Subject uses the imperative mood ("add", not "adding")
> > 5. Body wraps at 72 characters
> > 6. Body explains "what" and "why", not "how"
> > 
> > ### Documentation
> > * [x] In case of new functionality, my PR adds documentation that describes how to use it.
> > 
> > * All the public functions and the classes in the PR contain docstrings that explain what it does
> > * If you implement backwards incompatible changes, please leave a note in the [Updating.md](https://github.com/apache/airflow/blob/master/UPDATING.md) so we can assign it to a appropriate release
>  



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