Docker image

The repository now carries the Elassandra image build sources directly under distribution/docker. The Docker build reuses the assembled Linux distribution from this repository and overlays the Cassandra startup scripts and configuration needed to start org.apache.cassandra.service.ElassandraDaemon.

Build the image locally

From the repository root:

./gradlew :distribution:docker:buildDockerImage

The local tag produced by the Gradle task is:

elassandra:test

Start a single node

Run a local Elassandra container:

docker run --name node0 \
  -p 9042:9042 \
  -p 9200:9200 \
  -e MAX_HEAP_SIZE=1200m \
  -e HEAP_NEWSIZE=300m \
  -e JVM_OPTS=-Dcassandra.custom_query_handler_class=org.elassandra.index.ElasticQueryHandler \
  elassandra:test

Then inspect the node:

docker exec -it node0 nodetool status
docker exec -it node0 cqlsh
docker exec -it node0 curl localhost:9200

Supported environment variables

The image configures conf/cassandra.yaml and conf/cassandra-rackdc.properties from environment variables at container start. The first-pass runtime contract is intentionally small and matches the Helm chart values:

Variable	Description
CASSANDRA_LISTEN_ADDRESS	Cassandra listen address. Defaults to the container IP.
CASSANDRA_BROADCAST_ADDRESS	Gossip and broadcast address. Defaults to the listen address.
CASSANDRA_RPC_ADDRESS	CQL bind address. Defaults to 0.0.0.0.
CASSANDRA_BROADCAST_RPC_ADDRESS	CQL address advertised to clients.
CASSANDRA_SEEDS	Comma-separated seed hosts for gossip bootstrap.
CASSANDRA_CLUSTER_NAME	Cluster name written to cassandra.yaml.
CASSANDRA_NUM_TOKENS	Number of virtual nodes assigned to the container.
CASSANDRA_DC	Datacenter for cassandra-rackdc.properties.
CASSANDRA_RACK	Rack for cassandra-rackdc.properties.
CASSANDRA_ENDPOINT_SNITCH	Snitch implementation, usually GossipingPropertyFileSnitch.
MAX_HEAP_SIZE	JVM heap upper bound for Cassandra and Elassandra.
HEAP_NEWSIZE	Young-generation heap size.
JVM_OPTS	Additional JVM options. The image adds the Elassandra query handler if it is not already present.
DEBUG	Switch the packaged logback.xml root logger to DEBUG.

Filesystem layout

The image uses an installation rooted at /usr/share/elassandra:

• /usr/share/elassandra/bin: Cassandra and Elassandra startup scripts

• /usr/share/elassandra/conf: Cassandra and OpenSearch configuration

• /usr/share/elassandra/data: data, commitlog, hints, CDC, and saved caches

• /usr/share/elassandra/logs: log files

Exposed ports

• 7000: intra-node communication

• 7001: TLS intra-node communication

• 7199: JMX

• 9042: CQL

• 9160: thrift

• 9200: OpenSearch HTTP

• 9300: OpenSearch transport

Local cluster example

For a small local multi-node test environment, use ci/docker-compose.yml after building the image:

docker-compose -f ci/docker-compose.yml up -d --scale node=0
docker-compose -f ci/docker-compose.yml up -d --scale node=1

For long-lived containerized deployments, prefer the maintained Helm chart in incloudsio/helm-charts under charts/elassandra.