Let's assume, we have a legacy application, that we don't really want to change. It already has a sort-of health-check endpoint on JMX, but now we want to add this app, as the app component, to our monitoring, that does HTTP checks. With the Goss application, running as the goss component, we can have a range of system level checks we can execute, to tell if the application seems to be up, and is progressing. It still cannot do JMX checks, so we also add the exporter component, which runs a Prometheus JMX exporter, and we'll check its output with goss.
The JMX and HTTP connections are possible because of the shared network namespace. The progress tests are done by checking the contents of a file on a shared volume. This example uses some mock images for demonstration, you can see what they do in their respective sub-folder, if you're interested.
To deploy the stack straight from this repository:
$ curl -fsSL https://raw.githubusercontent.com/rycus86/podlike/master/examples/healthz/stack.yml | docker stack deploy -c - healthzThen you can check the health-check output:
$ curl -s http://127.0.0.1:8080/healthzOr try it on the Docker Playground.