Configuring Cassandra
The Cassandra configuration files location varies, depending on the
type of installation:
-
docker:
/etc/cassandradirectory -
tarball:
confdirectory within the tarball install location -
package:
/etc/cassandradirectory
Cassandra’s default configuration file, cassandra.yaml, is sufficient
to explore a simple single-node cluster. However, anything beyond
running a single-node cluster locally requires additional configuration
to various Cassandra configuration files. Some examples that require
non-default configuration are deploying a multi-node cluster or using
clients that are not running on a cluster node.
-
cassandra.yaml: the main configuration file for Cassandra -
cassandra-env.sh: environment variables can be set -
cassandra-rackdc.propertiesORcassandra-topology.properties: set rack and datacenter information for a cluster -
logback.xml: logging configuration including logging levels -
jvm-*: a number of JVM configuration files for both the server and clients -
commitlog_archiving.properties: set archiving parameters for thecommitlog
The sample configuration files can also be found in ./conf:
-
cqlshrc.sample: how the CQL shell, cqlsh, can be configured
Main runtime properties
Configuring Cassandra is done by setting yaml properties in the
cassandra.yaml file. At a minimum you should consider setting the
following properties:
-
cluster_name: Set the name of your cluster. -
seeds: A comma separated list of the IP addresses of your clusterseed nodes. -
storage_port: Check that you don’t have the default port of 7000 blocked by a firewall. -
listen_address: Thelisten addressis the IP address of a node that allows it to communicate with other nodes in the cluster. Set to localhost by default. Alternatively, you can setlisten_interfaceto tell Cassandra which interface to use, and consecutively which address to use. Set one property, not both. -
native_transport_port: Check that you don’t have the default port of 9042 blocked by a firewall, so that clients like cqlsh can communicate with Cassandra on this port.
Changing the location of directories
The following yaml properties control the location of directories:
-
data_file_directories: One or more directories where data files, likeSSTablesare located. -
commitlog_directory: The directory where commitlog files are located. -
saved_caches_directory: The directory where saved caches are located. -
hints_directory: The directory wherehintsare located.
For performance reasons, if you have multiple disks, consider putting commitlog and data files on different disks.
Environment variables
JVM-level settings such as heap size can be set in cassandra-env.sh.
You can add any additional JVM command line argument to the JVM_OPTS
environment variable; when Cassandra starts, these arguments will be
passed to the JVM.
Logging
The default logger is logback. By default it will log:
-
INFO level in
system.log -
DEBUG level in
debug.log
When running in the foreground, it will also log at INFO level to the
console. You can change logging properties by editing logback.xml or
by running the nodetool setlogginglevel command.
