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From Apache Wiki <>
Subject [Cassandra Wiki] Update of "ConfiguringCluster" by MakiWatanabe
Date Mon, 20 Feb 2012 10:47:03 GMT
Dear Wiki user,

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The "ConfiguringCluster" page has been changed by MakiWatanabe:

Instruction for configuring multi node cluster (draft)

+ ## Under construction ##
  ## page was copied from GettingStarted
- == Cassandra documentation from DataStax ==
- !DataStax's latest [[|Cassandra documentation]] covers
topics from installation to troubleshooting.  Documentation for older releases is also available.
- == Introduction ==
- This document aims to provide a few easy to follow steps to take the first-time user from
installation, to an operational Cassandra cluster.
- == Step 0: Prerequisites and connection to the community ==
- Cassandra requires the most stable version of Java 1.6 you can deploy.  For Sun's jvm, this
means at least u19; u21 is better.  Cassandra also runs on the IBM jvm, and should run on
jrockit as well.
- The best way to ensure you always have up to date information on the project, releases,
stability, bugs, and features is to subscribe to the users mailing list ([[|subscription
required]]) and participate in the #cassandra channel on [[|IRC]].
- <<Anchor(picking_a_version)>>
- == Step 1: Picking a version ==
- At any given time, there are a number of different versions available to install:
- === Stable releases ===
- Cassandra stable releases are well tested and reasonably free of serious problems, (or at
least the problems are known and well documented). If you are setting up a production environment,
a stable release is what you want.
- Download links for the latest stable release can always be found on the [[|website]].
- === Betas and release candidates ===
- Betas are prototype releases considered ready for user testing, and release candidates have
the potential to become the next stable release. These releases represent the state-of-the-art
so are often the best place to start, and since APIs and on-disk storage formats can change
between major versions this can also save you from an upgrade. The testing and feedback is
also highly appreciated.
- === Nightly builds ===
- Nightly builds represent the current state of development as of the time of the build. They
contain all of the previous day's new features, fixes, and newly introduced bugs. The only
guarantee they come with is that they successfully build and the unit tests pass. Nightly
builds are a handy way of testing recent changes, or accessing the latest features and fixes
not found in beta or release candidates, but there is some risk of them being buggy.
- The most recent nightly build can be downloaded [[|here]].
- === Git ===
- Cassandra's git repository is where all active development takes place. Anyone interested
in contributing to the project should use a checkout of trunk. If you do run from git, be
sure to update frequently, and subscribe to the [[|mailing
list]] to stay abreast of the latest developments.
- Instructions for checking out the source code can always be found on the [[|website]].
- <<Anchor(running_a_single_node)>>
- == Step 2: Running a single node ==
- Cassandra is meant to run on a cluster of nodes, but will run equally well on a single machine.
This is a handy way of getting familiar with the software while avoiding the complexities
of a larger system.
- Since there isn't currently an installation method per se, the easiest solution is to simply
run Cassandra from an extracted archive<<FootNote(Users of Debian or Debian-based derivatives
can install the latest stable release in package form, see DebianPackaging for details.)>><<FootNote(Users
of RPM-based distributions can get packages from [[|Datastax]])>>
or Git checkout (see: [[#picking_a_version|Picking a version]]). Also, unless you've downloaded
a binary distribution, you'll need to compile the software by invoking `ant` from the top-level
- The distribution's sample configuration `conf/cassandra.yaml` contains reasonable defaults
for single node operation, but you will need to make sure that the paths exist for `data_file_directories`,
`commitlog_directory`, and `saved_caches_directory`. Additionally, take a minute now to look
over the logging configuration in `conf/` and make sure that directories exist
for the configured log file(s) as well.
- Some people running OS X have trouble getting Java 6 to work. If you've kept up with Apple's
updates, Java 6 should already be installed (it comes in Mac OS X 10.5 Update 1). Unfortunately,
Apple does not default to using it. What you have to do is change your `JAVA_HOME` environment
setting to `/System/Library/Frameworks/JavaVM.framework/Versions/1.6/Home` and add `/System/Library/Frameworks/JavaVM.framework/Versions/1.6/Home/bin`
to the beginning of your `PATH`.
- And now for the moment of truth, start up Cassandra by invoking `bin/cassandra -f` from
the command line<<FootNote(To learn more about controlling the behavior of startup scripts,
see RunningCassandra.)>>. The service should start in the foreground and log gratuitously
to standard-out. Assuming you don't see messages with scary words like "error", or "fatal",
or anything that looks like a Java stack trace, then chances are you've succeeded. To be certain
though, take some time to try out the examples in CassandraCli before moving on (note: if
you are using Cassandra 0.7.0, you'll need to load the demo Keyspaces first using JMX, see, or even better follow testing instructions
on the README of the installation folder). Also, if you run into problems, Don't Panic, calmly
proceed to [[#if_something_goes_wrong|If Something Goes Wrong]].
- Users of recent Linux distributions and Mac OS X Snow Leopard should be able to start up
Cassandra simply by untarring and invoking `bin/cassandra -f` with root privileges. Snow Leopard
ships with Java 1.6.0 and does not require changing the `JAVA_HOME` environment variable or
adding any directory to your `PATH`. On Linux just make sure you have a working Java JDK package
installed such as the `openjdk-6-jdk` on Ubuntu Lucid Lynx.
- == Step 3: Running a cluster ==
+ == Running a cluster ==
  Setting up a Cassandra cluster is ''almost'' as simple as repeating [[#running_a_single_node|Step
2]] for each node in your cluster. There are a few minor exceptions though.
  Cassandra nodes exchange information about one another using a mechanism called Gossip,
but to get the ball rolling a newly started node needs to know of at least one other, this
is called a `Seed`. It's customary to pick a small number of relatively stable nodes to serve
as your seeds, but there is no hard-and-fast rule here. Do make sure that each seed also knows
of at least one other, remember, the goal is to avoid a chicken-and-egg scenario and provide
an avenue for all nodes in the cluster to discover one another.
@@ -71, +24 @@

  If you don't yet have access to hardware for a Cassandra cluster you can try it out on EC2
with CloudConfig.
- == Step 4: Write your application ==
- The recommended way to communicate with Cassandra in your application is to use a [[|higher-level
client]]. These provide programming language specific API:s for talking to Cassandra in a
variety of languages. The details will vary depending on programming language and client,
but in general using a higher-level client will mean that you have to write less code and
get several features for free that you would otherwise have to write yourself.
- That said, it is useful to know that Cassandra uses [[|Thrift]]
for its external client-facing API. Cassandra's main API/RPC/Thrift port is 9160. Thrift supports
a [[|wide variety of languages]] so you can
code your application to use Thrift directly if you so chose (but again we recommend a [[|high-level
client]] where available).
- Important note: If you intend to use thrift directly, you need to install a version of thrift
that matches the revision that your version of Cassandra uses. InstallThrift
- Cassandra's main API/RPC/Thrift port is 9160. It is a common mistake for API clients to
connect to the JMX port instead.
- Checking out a demo application like [[|Twissandra]]
(Python + Django) will also be useful.
- <<Anchor(if_something_goes_wrong)>>
- == If Something Goes Wrong ==
- If you followed the steps in this guide and failed to get up and running, we'd love to help.
Here's what we need.
-  1. If you are running anything other than a stable release, please upgrade first and see
if you can still reproduce the problem.
-  1. Make sure debug logging is enabled (hint: `conf/`) and save a copy of
the output.
-  1. Search the [[|mailing list archive]]
and see if anyone has reported a similar problem and what, if any resolution they received.
-  1. Ditto for the [[|bug tracking system]].
-  1. See if you can put together a unit test, script, or application that reproduces the
- Finally, post a message with all relevant details to the list ([[|subscription
required]]), or hop onto [[|IRC]] (network, channel #cassandra) and let us know.
- <<BR>> <<BR>>

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