How to add discovery.type=single-node in my Dockerfile

Question

I had a node app running Docker with elastic search 7. I want to add this option

discovery.type=single-node

to elasticsearch services. How can I add that to Dockerfile?

Answer 1

For that, you have to add an environment file elasticsearch.env with contents like this.

cluster.name=my-elasticsearch-cluster
network.host=0.0.0.0
bootstrap.memory_lock=true
discovery.type=single-node # Here you can add that 

After that, mention the env file in your docker-compose.yml

   // ....

  elastic:
    image: elasticsearch:7.16.2
    ports: 
     - "9200:9200"
    env_file:
      - ./elasticsearch.env
    volumes:
      - ./data/elasticsearch:/usr/share/elasticsearch/data
   // ....

Answer 2

With plain Docker like this (from the docs ):

docker run -p 127.0.0.1:9200:9200 -p 127.0.0.1:9300:9300 -e "discovery.type=single-node" docker.elastic.co/elasticsearch/elasticsearch:7.16.2

You don't add it to the Dockerfile directly normally to keep the image usable for single and multi node clusters. Passing in the environment variable does the job.