Add HEALTHCHECK instruction

[ebuildy]

HEALTHCHECK instruction (added in Docker 1.12) is very powerful and useful for data-base (because usually other containers will depend on). (more at https://blog.newrelic.com/2016/08/24/docker-health-check-instruction/).

This will tell if elasticsearch is up or not (not the container, but elasticsearch itself).

I think a simple

HEALTHCHECK CMD curl --fail http://localhost:9200/ || exit 1

Could do the trick.

[yosifkit]

Copying comment from docker-library/cassandra#76 (comment)

I do not feel that generalized healthchecks on the official images are really that useful.

• users will have their own idea of what is "healthy"
• it does not actually test that the service is listening to connections outside of localhost (see https://github.com/docker-library/healthcheck for some examples that do more than what's proposed here, including attempting to check whether the service is listening remotely)
  • some of the Official Images even purposely start in a localhost only mode for database initialization and then kill and start the main service with full network availability
• after upgrading their images, current users will have extra unexpected load on their systems for healthchecks they don't necessarily need/want and may be unaware of

[tianon]

This image is officially deprecated in favor of upstream's images (see https://www.elastic.co/guide/en/elasticsearch/reference/current/docker.html).

For more information, please see #160, docker-library/docs#842, and docker-library/docs#945.

This image has been deprecated in favor of the official elasticsearch image provided and maintained by elastic.co. The upstream images are available to pull via docker.elastic.co/elasticsearch/elasticsearch:[version] like 5.4.2. The images found here will receive no further updates once the 5.6.0 release is available upstream. Please adjust your usage accordingly.

Elastic provides open-source support for Elasticsearch via the elastic/elasticsearch GitHub repository and the Docker image via the elastic/elasticsearch-docker GitHub repository, as well as community support via its forums.

Thanks!