A script/library to create, launch and remove an Apache Cassandra cluster on localhost.

The goal of ccm and ccmlib is to make it easy to create, manage and destroy a small Cassandra cluster on a local box. It is meant for testing a Cassandra cluster.

• A working python installation (tested to work with python 2.7).

• pyYAML (http://pyyaml.org/ -- sudo easy_install pyYaml)

• six (https://pypi.python.org/pypi/six -- sudo easy_install six)

• ant (http://ant.apache.org/, on Mac OS X, brew install ant)

• psutil (https://pypi.python.org/pypi/psutil)

• Java (which version depends on the version of Cassandra you plan to use. If unsure, use Java 7 as it is known to work with current versions of Cassandra).

• ccm only works on localhost for now. If you want to create multiple node clusters, the simplest way is to use multiple loopback aliases. On modern linux distributions you probably don't need to do anything, but on Mac OS X, you will need to create the aliases with

  sudo ifconfig lo0 alias 127.0.0.2 up
  sudo ifconfig lo0 alias 127.0.0.3 up
  ...
  

  Note that the usage section assumes that at least 127.0.0.1, 127.0.0.2 and 127.0.0.3 are available.

Windows only:

• node start pops up a window, stealing focus.
• cli and cqlsh started from ccm show incorrect prompts on command-prompt
• non nodetool-based command-line options fail (sstablesplit, scrub, etc)
• cli_session does not accept commands.
• To install psutil, you must use the .msi from pypi. pip install psutil will not work
• You will need ant.bat in your PATH in order to build C* from source
• Until #191 is fixed, you need to run with an Unrestricted Powershell Execution-Policy

ccm uses python distutils so from the source directory run:

sudo ./setup.py install

MacPorts has ccm available as a port:

sudo port -v sync && sudo port -v install ccm

Let's say you wanted to fire up a 3 node Cassandra cluster.

ccm create test -v 2.0.5 -n 3 -s

You will of course want to replace 2.0.5 by whichever version of Cassandra you want to test.

ccm works from a Cassandra source tree (not the jars). There are two ways to tell ccm how to find the sources:

1. If you have downloaded and compiled Cassandra sources, you can ask ccm to use those by initiating a new cluster with:

   ccm create test --install-dir=<path/to/cassandra-sources>

   or, from that source tree directory, simply

    ccm create test
   

2. You can ask ccm to use a released version of Cassandra. For instance to use Cassandra 2.0.5, run

    ccm create test -v 2.0.5
   

   ccm will download the source (from http://archive.apache.org/dist/cassandra), compile it, and set the new cluster to use it. This means that this command can take a few minutes the first time you create a cluster for a given version. ccm saves the compiled source in ~/.ccm/repository/, so creating a cluster for that version will be much faster the second time you run it (note however that if you create a lot of clusters with different versions, this will take up disk space).

Once the cluster is created, you can populate it (with 3 nodes) and start all the nodes with:

ccm populate -n 3
ccm start

That will start 3 nodes on IP 127.0.0.[1, 2, 3] on port 9160 for thrift, port 7000 for the internal cluster communication and ports 7100, 7200 and 7300 for JMX. You can check that the cluster is correctly set up with

ccm node1 ring

You can then bootstrap a 4th node with

ccm add node4 -i 127.0.0.4 -j 7400 -b

(populate is just a shortcut for adding multiple nodes initially)

ccm provides a number of conveniences, like flushing all of the nodes of the cluster:

ccm flush

or only one node:

ccm node2 flush

You can also easily look at the log file of a given node with:

ccm node1 showlog

Finally, you can get rid of the whole cluster (which will stop the node and remove all the data) with

ccm remove

The list of other provided commands is available through

ccm

Each command is then documented through the -h (or --help) flag. For instance ccm add -h describes the options for ccm add.

By default, ccm stores all the node data and configuration files under ~/.ccm/cluster_name/. This can be overridden using the --config-dir option with each command.

CCM 2.0 supports creating and interacting with DSE clusters. The --dse option must be used with the ccm create command. See the ccm create -h help for assistance.

The ccm facilities are available programmatically through ccmlib. This could be used to implement automated tests again Cassandra. A simple example of how to use ccmlib follows:

import ccmlib

CLUSTER_PATH="."
cluster = ccmlib.Cluster(CLUSTER_PATH, 'test', cassandra_version='2.0.5')
cluster.populate(3).start()
[node1, node2, node3] = cluster.nodelist()

# do some tests on the cluster/nodes. To connect to a node through thrift,
# the host and port to a node is available through
#   node.network_interfaces['thrift']

cluster.flush()
node2.compact()

# do some other tests

# after the test, you can leave the cluster running, you can stop all nodes
# using cluster.stop() but keep the data around (in CLUSTER_PATH/test), or
# you can remove everything with cluster.remove()

-- Sylvain Lebresne [email protected]