cloudera hadoop hdfs master ^#0

Overview

The Apache Hadoop software library is a framework that allows for the distributed processing of large data sets across clusters of computers using a simple programming model.

This charm deploys an HDFS master node running the NameNode component of Apache Hadoop 2.4.1, which manages the distribution and replication of data among the various DataNode components.

Usage

This charm is intended to be deployed via one of the apache bundles. For example:

juju quickstart apache-analytics-sql

This will deploy the Apache Hadoop platform with Apache Hive available to perform SQL-like queries against your data.

You can also manually load and run map-reduce jobs via the plugin charm included in the bigdata bundles linked above:

juju scp my-job.jar plugin/0:
juju ssh plugin/0
hadoop jar my-job.jar

Status and Smoke Test

The services provide extended status reporting to indicate when they are ready:

juju status --format=tabular

This is particularly useful when combined with watch to track the on-going progress of the deployment:

watch -n 0.5 juju status --format=tabular

The message for each unit will provide information about that unit's state. Once they all indicate that they are ready, you can perform a "smoke test" to verify that HDFS is working as expected using the built-in smoke-test action:

juju action do smoke-test

After a few seconds or so, you can check the results of the smoke test:

juju action status

You will see status: completed if the smoke test was successful, or status: failed if it was not. You can get more information on why it failed via:

juju action fetch <action-id>

Monitoring

This charm supports monitoring via Ganglia. To enable monitoring, you must do both of the following (the order does not matter):

• Add a relation to the Ganglia charm via the :master relation
• Enable the ganglia_metrics config option

For example:

juju add-relation hdfs-master ganglia:master
juju set hdfs-master ganglia_metrics=true

Enabling monitoring will issue restart the NameNode and all DataNode components on all of the related compute-slaves. Take care to ensure that there are no running jobs when enabling monitoring.

Deploying in Network-Restricted Environments

The Apache Hadoop charms can be deployed in environments with limited network access. To deploy in this environment, you will need a local mirror to serve the packages and resources required by these charms.

Mirroring Packages

You can setup a local mirror for apt packages using squid-deb-proxy. For instructions on configuring juju to use this, see the Juju Proxy Documentation.

Mirroring Resources

In addition to apt packages, the Apache Hadoop charms require a few binary resources, which are normally hosted on Launchpad. If access to Launchpad is not available, the jujuresources library makes it easy to create a mirror of these resources:

sudo pip install jujuresources
juju-resources fetch --all /path/to/resources.yaml -d /tmp/resources
juju-resources serve -d /tmp/resources

This will fetch all of the resources needed by this charm and serve them via a simple HTTP server. The output from juju-resources serve will give you a URL that you can set as the resources_mirror config option for this charm. Setting this option will cause all resources required by this charm to be downloaded from the configured URL.

You can fetch the resources for all of the Apache Hadoop charms (apache-hadoop-hdfs-master, apache-hadoop-yarn-master, apache-hadoop-hdfs-secondary, apache-hadoop-plugin, etc) into a single directory and serve them all with a single juju-resources serve instance.

Contact Information

• bigdata-dev@lists.launchpad.net

Hadoop

• Apache Hadoop home page
• Apache Hadoop bug trackers
• Apache Hadoop mailing lists
• Apache Hadoop Juju Charm