huntc / docker-registry-conductr-bundle

EXPERIMENTAL - DO NOT USE

Example Docker Registry as a ConductR Bundle

Example of running a Docker v2 registry container on ConductR

Use

Run sbt bundle:dist generate a bundle that can be loaded and started in ConductR.

Right now just one instance can be scaled as the registry will require further work to be backed by Redis (for example).

The bundle will make the docker registry available on $SERVICE_PROXY:5000. $SERVICE_PROXY indicates where ConductR's proxy is running. It is important to use the proxy's IP address as bundle execution i.e. other bundles that require the registry, may not be running on the same machine; particularly in a Mesos situation.

Our goal is for another bundle to be able to address the ConductR hosted repository like so service-proxy:5000/ubuntu (supposing it is the Ubuntu image to be addressed). In order to achieve this the Docker daemon on each node where a bundle may execute must be configured to accept service-proxy:5000 without TLS and without authentication i.e. the service-proxy based registry is trusted within the ConductR cluster. From the Docker documentation then:

1. edit the file /etc/default/docker so that there is a line that reads: DOCKER\_OPTS="--insecure-registry service-proxy:5000" (or add that to existing DOCKER_OPTS)
2. restart your Docker daemon: on ubuntu, this is usually service docker restart

Add an entry to your /etc/hosts (just for this experiment) so that service-proxy resolves to 10.0.2.15.

As an exercise, once you load and run the registry on ConductR, do the following in order to copy a cached image into the new registry (we'll copy the registry image):

> docker pull registry
> docker images
REPOSITORY                                                                                    TAG                           IMAGE ID            CREATED             VIRTUAL SIZE
registry                                                                                      2                             2f1ef7702586        13 days ago         220.6 MB

2f1ef7702586 must now be tagged with the private registry:

docker tag 2f1ef7702586 service-proxy:5000/registry

You are now in a position to push it to the ConductR hosted registry:

docker push service-proxy:5000/registry

For fun, let's pull that image back down:

docker pull service-proxy:5000/registry

Bundles

For bundles to be able to resolve addresses of the form service-proxy:5000/xxx where xxx is the image, you need to add the service-proxy resolution to the address of a proxy. For example, each machine that runs a bundle should have a service-proxy entry for a proxy in its /etc/hosts file, or establish a DNS server that holds entries for all known proxies.