Sharing Logstash keystore between multiple Logstash containers.

February 2021

Create the keystore in one of the containers:

docker-compose exec logstash-example /usr/share/logstash/bin/logstash-keystore create

Copy the file from within the container to an outside folder, this is to be shared with the rest of the containers

To add a new key, just execute in any of the containers:

docker-compose exec logstash-example /usr/share/logstash/bin/logstash-keystore add ES_PWD

Confirm the keystore was created with

docker-compose exec logstash-example /usr/share/logstash/bin/logstash-keystore list

To use the keystore in a container you should pass:
- the keystore file as a volume:
```
${PWD}/keystore/logstash.keystore:/usr/share/logstash/config/logstash.keystore
```
- and the keystore master password as the environment variable LOGSTASH_KEYSTORE_PASSWORD :

Full docker compose example

  logstash:
    image: docker.elastic.co/logstash/logstash:8.2.3
    volumes:
      # - ...
      - ${PWD}/keystore/logstash.keystore:/usr/share/logstash/config/logstash.keystore
  environment:
    LS_JAVA_OPTS: "-Xms1024m -Xmx1024m"
    LOGSTASH_KEYSTORE_PASS: "${LOGSTASH_KEYSTORE_PASS}"