Clustering using JMS Plugin

GeoServer supports clustering using JMS cluster plugin or using the ActiveMQ-broker.

JMS cluster plugin

This setup uses the JMS cluster plugin which uses an embedded broker. A docker-compose.yml is provided in the clustering folder which simulates the replication using a shared data directory.

The environment variables associated with replication are listed below

• CLUSTERING=True - Specified whether clustering should be activated.
• BROKER_URL=tcp://0.0.0.0:61661 - This links to the internal broker provided by the JMS cluster plugin. This value will be different for (Master-Node)
• READONLY=disabled - Determines if the GeoServer instance is Read only
• RANDOMSTRING=87ee2a9b6802b6da_master - Used to create a unique CLUSTER_CONFIG_DIR for each instance. Not mandatory as the container can self generate this.
• INSTANCE_STRING=d8a167a4e61b5415ec263 - Used to differentiate cluster instance names. Not mandatory as the container can self generate this.
• CLUSTER_DURABILITY=false
• TOGGLE_MASTER=true - Differentiates if the instance will be a Master
• TOGGLE_SLAVE=true - Differentiates if the instance will be a Node
• EMBEDDED_BROKER=disabled - Should be disabled for the Node
• CLUSTER_CONNECTION_RETRY_COUNT=10 - How many times try to connect to broker
• CLUSTER_CONNECTION_MAX_WAIT=500 - Wait time between connection to broker retry (in milliseconds)
• EXISTING_DATA_DIR - If you are using an existing data directory, you need to set CLUSTER_CONFIG_DIR otherwise the container is will hang and not start. Additionally, it will check if all the files needed for clustering exists, otherwise it will fail.

ActiveMQ-broker

You can additionally run the clustering using an external broker. To run this you will need to build the image locally and run the stack:

docker compose -f docker-compose-external.yml up -d --build

or run in a single step

docker compose -f docker-compose-external.yml up -d