Skip to content
Closed
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
145 changes: 74 additions & 71 deletions docs/running-on-yarn.md
Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,80 @@ Running Spark-on-YARN requires a binary distribution of Spark which is built wit
Binary distributions can be downloaded from the Spark project website.
To build Spark yourself, refer to [Building Spark](building-spark.html).


# Launching Spark on YARN

Ensure that `HADOOP_CONF_DIR` or `YARN_CONF_DIR` points to the directory which contains the configuration files for the Hadoop cluster.
These configs are used to write to the dfs and connect to the YARN ResourceManager.

There are two deploy modes that can be used to launch Spark applications on YARN. In yarn-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 yarn-client mode, the driver runs in the client process(offen on different machine), and the application master is only used for requesting resources from YARN. The differences between them are that in yarn-cluster mode, yarn manages the Spark application, including resources(like memory and cpu) and status, while in yarn-cluster mode, Spark just asks yarn for enough resources to accomplish it's work, everything else is done by Spark.

Unlike in Spark standalone and Mesos mode, in which the master's address is specified in the "master" parameter, in YARN mode the ResourceManager's address is picked up from the Hadoop configuration. Thus, the master parameter is simply "yarn-client" or "yarn-cluster".

To launch a Spark application in yarn-cluster mode:

./bin/spark-submit --class path.to.your.Class --master yarn-cluster [options] <app jar> [app options]

For example:

$ ./bin/spark-submit --class org.apache.spark.examples.SparkPi \
--master yarn-cluster \
--num-executors 3 \
--driver-memory 4g \
--executor-memory 2g \
--executor-cores 1 \
--queue thequeue \
lib/spark-examples*.jar \
10

The above starts a YARN client program which starts the default Application Master. Then SparkPi will be run as a child thread of Application Master. The client will periodically poll the Application Master for status updates and display them in the console. The client will exit once your application has finished running. Refer to the "Viewing Logs" section below for how to see driver and executor logs.

To launch a Spark application in yarn-client mode, do the same, but replace "yarn-cluster" with "yarn-client". To run spark-shell:

$ ./bin/spark-shell --master yarn-client

## Adding Other JARs

In yarn-cluster mode, the driver runs on a different machine than the client, so `SparkContext.addJar` won't work out of the box with files that are local to the client. To make files on the client available to `SparkContext.addJar`, include them with the `--jars` option in the launch command.

$ ./bin/spark-submit --class my.main.Class \
--master yarn-cluster \
--jars my-other-jar.jar,my-other-other-jar.jar
my-main-jar.jar
app_arg1 app_arg2

# Debugging your Application

In YARN terminology, executors and application masters run inside "containers", the containers in YARN are used to represent a series of resources(only cpu and memory right now). YARN has two modes for handling container logs after an application has completed. If log aggregation is turned on (with the `yarn.log-aggregation-enable` config), container logs are copied to HDFS and deleted on the local machine. These logs can be viewed from anywhere on the cluster with the "yarn logs" command.

yarn logs -applicationId <app ID>

will print out the contents of all log files from all containers from the given application.

When log aggregation isn't turned on, logs are retained locally on each machine under `YARN_APP_LOGS_DIR`, which is usually configured to `/tmp/logs` or `$HADOOP_HOME/logs/userlogs` depending on the Hadoop version and installation. Viewing logs for a container requires going to the host that contains them and looking in this directory. Subdirectories organize log files by application ID and container ID.

To review per-container launch environment, increase `yarn.nodemanager.delete.debug-delay-sec` to a
large value (e.g. 36000), and then access the application cache through `yarn.nodemanager.local-dirs`
on the nodes on which containers are launched. This directory contains the launch script, JARs, and
all environment variables used for launching each container. This process is useful for debugging
classpath problems in particular. (Note that enabling this requires admin privileges on cluster
settings and a restart of all node managers. Thus, this is not applicable to hosted clusters).

To use a custom log4j configuration for the application master or executors, there are two options:

- upload a custom log4j.properties using spark-submit, by adding it to the "--files" list of files
to be uploaded with the application.
- add "-Dlog4j.configuration=<location of configuration file>" to "spark.driver.extraJavaOptions"
(for the driver) or "spark.executor.extraJavaOptions" (for executors). Note that if using a file,
the "file:" protocol should be explicitly provided, and the file needs to exist locally on all
the nodes.

Note that for the first option, both executors and the application master will share the same
log4j configuration, which may cause issues when they run on the same node (e.g. trying to write
to the same log file).

If you need a reference to the proper location to put log files in the YARN so that YARN can properly display and aggregate them, use "${spark.yarn.app.container.log.dir}" in your log4j.properties. For example, log4j.appender.file_appender.File=${spark.yarn.app.container.log.dir}/spark.log. For streaming application, configuring RollingFileAppender and setting file location to YARN's log directory will avoid disk overflow caused by large log file, and logs can be accessed using YARN's log utility.

# Configuration

Most of the configs are the same for Spark on YARN as for other deployment modes. See the [configuration page](configuration.html) for more information on those. These are configs that are specific to Spark on YARN.
Expand Down Expand Up @@ -134,78 +208,7 @@ Most of the configs are the same for Spark on YARN as for other deployment modes
</tr>
</table>

# Launching Spark on YARN

Ensure that `HADOOP_CONF_DIR` or `YARN_CONF_DIR` points to the directory which contains the (client side) configuration files for the Hadoop cluster.
These configs are used to write to the dfs and connect to the YARN ResourceManager.

There are two deploy modes that can be used to launch Spark applications on YARN. In yarn-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 yarn-client mode, the driver runs in the client process, and the application master is only used for requesting resources from YARN.

Unlike in Spark standalone and Mesos mode, in which the master's address is specified in the "master" parameter, in YARN mode the ResourceManager's address is picked up from the Hadoop configuration. Thus, the master parameter is simply "yarn-client" or "yarn-cluster".

To launch a Spark application in yarn-cluster mode:

./bin/spark-submit --class path.to.your.Class --master yarn-cluster [options] <app jar> [app options]

For example:

$ ./bin/spark-submit --class org.apache.spark.examples.SparkPi \
--master yarn-cluster \
--num-executors 3 \
--driver-memory 4g \
--executor-memory 2g \
--executor-cores 1 \
--queue thequeue \
lib/spark-examples*.jar \
10

The above starts a YARN client program which starts the default Application Master. Then SparkPi will be run as a child thread of Application Master. The client will periodically poll the Application Master for status updates and display them in the console. The client will exit once your application has finished running. Refer to the "Viewing Logs" section below for how to see driver and executor logs.

To launch a Spark application in yarn-client mode, do the same, but replace "yarn-cluster" with "yarn-client". To run spark-shell:

$ ./bin/spark-shell --master yarn-client

## Adding Other JARs

In yarn-cluster mode, the driver runs on a different machine than the client, so `SparkContext.addJar` won't work out of the box with files that are local to the client. To make files on the client available to `SparkContext.addJar`, include them with the `--jars` option in the launch command.

$ ./bin/spark-submit --class my.main.Class \
--master yarn-cluster \
--jars my-other-jar.jar,my-other-other-jar.jar
my-main-jar.jar
app_arg1 app_arg2

# Debugging your Application

In YARN terminology, executors and application masters run inside "containers". YARN has two modes for handling container logs after an application has completed. If log aggregation is turned on (with the `yarn.log-aggregation-enable` config), container logs are copied to HDFS and deleted on the local machine. These logs can be viewed from anywhere on the cluster with the "yarn logs" command.

yarn logs -applicationId <app ID>

will print out the contents of all log files from all containers from the given application.

When log aggregation isn't turned on, logs are retained locally on each machine under `YARN_APP_LOGS_DIR`, which is usually configured to `/tmp/logs` or `$HADOOP_HOME/logs/userlogs` depending on the Hadoop version and installation. Viewing logs for a container requires going to the host that contains them and looking in this directory. Subdirectories organize log files by application ID and container ID.

To review per-container launch environment, increase `yarn.nodemanager.delete.debug-delay-sec` to a
large value (e.g. 36000), and then access the application cache through `yarn.nodemanager.local-dirs`
on the nodes on which containers are launched. This directory contains the launch script, JARs, and
all environment variables used for launching each container. This process is useful for debugging
classpath problems in particular. (Note that enabling this requires admin privileges on cluster
settings and a restart of all node managers. Thus, this is not applicable to hosted clusters).

To use a custom log4j configuration for the application master or executors, there are two options:

- upload a custom log4j.properties using spark-submit, by adding it to the "--files" list of files
to be uploaded with the application.
- add "-Dlog4j.configuration=<location of configuration file>" to "spark.driver.extraJavaOptions"
(for the driver) or "spark.executor.extraJavaOptions" (for executors). Note that if using a file,
the "file:" protocol should be explicitly provided, and the file needs to exist locally on all
the nodes.

Note that for the first option, both executors and the application master will share the same
log4j configuration, which may cause issues when they run on the same node (e.g. trying to write
to the same log file).

If you need a reference to the proper location to put log files in the YARN so that YARN can properly display and aggregate them, use "${spark.yarn.app.container.log.dir}" in your log4j.properties. For example, log4j.appender.file_appender.File=${spark.yarn.app.container.log.dir}/spark.log. For streaming application, configuring RollingFileAppender and setting file location to YARN's log directory will avoid disk overflow caused by large log file, and logs can be accessed using YARN's log utility.

# Important notes

Expand Down