| # Flink YARN tests |
| |
| `flink-yarn-test` collects test cases which are deployed to a local Apache Hadoop YARN cluster. |
| There are several things to consider when running these tests locally: |
| |
| * `YarnTestBase` spins up a `MiniYARNCluster`. This cluster spawns processes outside of the IDE's JVM |
| to run the workers on. `JAVA_HOME` needs to be set to make this work. |
| * The Flink cluster within each test is deployed using the `flink-dist` binaries. Any changes made |
| to the code will only take effect after rebuilding the `flink-dist` module. |
| * Each `YARN*ITCase` will have a local working directory for resources like logs to be stored. These |
| working directories are located in `flink-yarn-tests/target/` (see |
| `find flink-yarn-tests/target -name "*.err" -or -name "*.out"` for the test's output). |
| * There is a known problem causing test instabilities due to our usage of Hadoop 2.8.3 executing the |
| tests. This is caused by a bug [YARN-7007](https://issues.apache.org/jira/browse/YARN-7007) that |
| got fixed in [Hadoop 2.8.6](https://issues.apache.org/jira/projects/YARN/versions/12344056). See |
| [FLINK-15534](https://issues.apache.org/jira/browse/FLINK-15534) for further details on the |
| related discussion. |
