Monthly Archives: March 2016

get the driver’s IP in spark yarn-cluster mode

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In cluster mode, the Spark driver runs inside an application master process which is managed by YARN on the cluster, and the client can go away after initiating the application. In client mode, the driver runs in the client process, and the application master is only used for requesting resources from YARN.

Sometimes we will have a bunch of logs for a terminated cluster and we need to find out which node was the driver in cluster mode.

Searching for “driverUrl” on the application/container logs, we will find it

find . -iname "*.gz" | xargs zgrep "driverUrl"
./container_1459071485818_0006_02_000001/stderr.gz:15/03/28 05:10:47 INFO YarnAllocator: Launching ExecutorRunnable. driverUrl: spark://CoarseGrainedScheduler@172.31.16.15:47452,  executorHostname: ip-172-31-16-13.ec2.internal
...
./container_1459071485818_0006_02_000001/stderr.gz:15/03/28 05:10:47 INFO YarnAllocator: Launching ExecutorRunnable. driverUrl: spark://CoarseGrainedScheduler@172.31.16.15:47452,  executorHostname: ip-172-31-16-14.ec2.internal

On this case the driver was running on 172.31.16.15.

Consider boosting spark.yarn.executor.memoryOverhead

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This is a very specific error related to the Spark Executor and the YARN container coexistence.

You will typically see errors like this one on the application container logs:

15/03/12 18:53:46 WARN YarnAllocator: Container killed by YARN for exceeding memory limits. 9.3 GB of 9.3 GB physical memory used. Consider boosting spark.yarn.executor.memoryOverhead.
15/03/12 18:53:46 ERROR YarnClusterScheduler: Lost executor 21 on ip-xxx-xx-xx-xx: Container killed by YARN for exceeding memory limits. 9.3 GB of 9.3 GB physical memory used. Consider boosting spark.yarn.executor.memoryOverhead.

To overcome this, you need to keep in mind how Yarn container and the executor are set in memory:

spark-tuning-yarn-memory

Memory used by Spark Executor is exceeding the predefined limits (often caused by a few spikes) and that is causing YARN to kill the container with the previously mentioned message error.

By default ‘spark.yarn.executor.memoryOverhead’ parameter is set to 384 MB. This value could be low depending on your application and the data load.

Suggested value for this parameter is ‘executorMemory * 0.10’.

We can increase the value for ‘spark.yarn.executor.memoryOverhead’ to 1GB on spark-submit bu adding this to the command line:

–conf spark.yarn.executor.memoryOverhead=1024

For reference, this fix was added on Jira 1930:

+  <td><code>spark.yarn.executor.memoryOverhead</code></td>