Installing Accumulo

This document covers installing Accumulo on single and multi-node environments.
Either download or build a binary distribution of Accumulo from
source code. Unpack as follows.

cd <install location>
tar xzf <some dir>/accumulo-X.Y.Z-bin.tar.gz
cd accumulo-X.Y.Z

Accumulo has some optional native code that improves its performance and
stability. Before configuring Accumulo attempt to build this native code
with the following command.

./bin/build_native_library.sh

If the command fails, its ok to continue with setup and resolve the issue
later.

Configuring

The Accumulo conf directory needs to be populated with initial config files.
The following script is provided to assist with this. Run the script and
answer the questions. When the script ask about memory-map type, choose Native
if the build native script was successful. Otherwise choose Java.

./bin/bootstrap_config.sh

The script will prompt for memory usage. Please note that the footprints are
only for the Accumulo system processes, so ample space should be left for other
processes like hadoop, zookeeper, and the accumulo client code. If Accumulo
worker processes are swapped out and unresponsive, they may be killed.

After this script runs, the conf directory should be populated and now a few
edits are needed.

Secret

Accumulo coordination and worker processes can only communicate with each other
if they share the same secret key. To change the secret key set
instance.secret in conf/accumulo-site.xml. Changing this secret key from
the default is highly recommended.

Dependencies

Accumulo requires running Zookeeper and HDFS instances. Also, the
Accumulo binary distribution does not include jars for Zookeeper and Hadoop.
When configuring Accumulo the following information about these dependencies
must be provided.

• Location of Zookeepers : Provide this by setting instance.zookeeper.host
  in conf/accumulo-site.xml.
• Where to store data : Provide this by setting instance.volumes in
  conf/accumulo-site.xml. If your namenode is running at 192.168.1.9:9000
  and you want to store data in /accumulo in HDFS, then set
  instance.volumes to hdfs://192.168.1.9:9000/accumulo.
• Location of Zoookeeper and Hadoop jars : Setting ZOOKEEPER_HOME and
  HADOOP_PREFIX in conf/accumulo-env.sh will help Accumulo find these
  jars.

If Accumulo has problems later on finding jars, then run bin/accumulo
classpath to print out info about where Accumulo is finding jars. If the
settings mentioned above are correct, then inspect general.classpaths in
conf/accumulo-site.xml.

Initialization

Accumulo needs to initialize the locations where it stores data in Zookeeper
and HDFS. The following command will do this.

./bin/accumulo init

The initialization command will prompt for the following information.

• Instance name : This is the name of the Accumulo instance and its
  Accumulo clients need to know it inorder to connect.
• Root password : Initialization sets up an initial Accumulo root user and
  prompts for its password. This information will be needed to later connect
  to Accumulo.

Multiple Nodes

Skip this section if running Accumulo on a single node. Accumulo has
coordinating, monitoring, and worker processes that run on specified nodes in
the cluster. The following files should be populated with a newline separated
list of node names. Must change from localhost.

• conf/masters : Accumulo primary coordinating process. Must specify one
  node. Can specify a few for fault tolerance.
• conf/gc : Accumulo garbage collector. Must specify one node. Can
  specify a few for fault tolerance.
• conf/monitor : Node where Accumulo monitoring web server is run.
• conf/slaves : Accumulo worker processes. List all of the nodes where
  tablet servers should run in this file.
• conf/tracers : Optional capability. Can specify zero or more nodes.

The Accumulo, Hadoop, and Zookeeper software should be present at the same
location on every node. Also the files in the conf directory must be copied
to every node. There are many ways to replicate the software and
configuration, two possible tools that can help replicate software and/or
config are pdcp and prsync.

Starting Accumulo

The Accumulo scripts use ssh to start processes on remote nodes. Before
attempting to start Accumulo, passwordless ssh must be setup on the
cluster.

After configuring and initializing Accumulo, use the following command to start
it.

./bin/start-all.sh

First steps

Once the start-all.sh script completes, use the following command to run the
Accumulo shell.

./bin/accumulo shell -u root

Use your web browser to connect the Accumulo monitor page on port 50095.

http://<hostname in conf/monitor>:50095/

When finished, use the following command to stop Accumulo.

./bin/stop-all.sh