FresherTechnicalElasticsearch

How do you run Elasticsearch locally with Docker and send a first request?

Try answering first

Model answer

Run a single-node container with the official image, then call it over HTTPS.

docker run -d --name es01 -p 127.0.0.1:9200:9200 \
  -e "discovery.type=single-node" \
  -e "ES_JAVA_OPTS=-Xms1g -Xmx1g" -m 2GB \
  docker.elastic.co/elasticsearch/elasticsearch:9.0.0

docker cp es01:/usr/share/elasticsearch/config/certs/http_ca.crt .
curl --cacert http_ca.crt -u elastic:$ELASTIC_PASSWORD https://localhost:9200

Points to know:

On first start, Elasticsearch 8 and later enable security: TLS for HTTP and a generated password for the elastic user, printed in the container logs. Reset it with docker exec -it es01 bin/elasticsearch-reset-password -u elastic.
discovery.type=single-node skips the cluster bootstrap checks that a one-node development setup cannot satisfy.
Set the JVM heap to half of the container memory, and on a Linux host raise vm.max_map_count to 262144.
Without a volume (-v esdata:/usr/share/elasticsearch/data), data disappears when the container is removed.
A successful call returns JSON with the cluster name, the version and the tagline You Know, for Search.

Bind to localhost, keep security on, and mount a volume if the data matters.

Key points

Single-node discovery for local development
Security and TLS are on by default in 8 and later
Heap at half of container memory, vm.max_map_count raised
A volume keeps data after the container is removed

Likely follow-ups

How do you add Kibana to this setup?
Why is a one-node cluster yellow for indices with replicas?

Common mistakes

Disabling security and exposing port 9200 on all interfaces
Forgetting the memory limits and getting OOM-killed