Using the Docker Healthcheck Command

Docker 1.12 introduced a new feature allowing health checks to be integrated into the container's image definition, which can also be overridden via the command line. This feature is crucial as it provides a method for the application inside the container to report its health status, rather than just indicating whether the container is up. The Dockerfile for the arungupta/couchbase image includes a health check instruction that verifies the health of the container by executing a command that checks the availability of a Couchbase REST API endpoint every 5 seconds, with a timeout of 3 seconds. If the health check command fails, the container's status is marked as unhealthy, and Docker's exit status reflects this, with 0 indicating a healthy container and 1 indicating an unhealthy one. Users can also specify health check commands at runtime using the docker run command if the image does not include a HEALTHCHECK instruction. This feature enhances container management by allowing users to monitor the health status of their applications more effectively.