Romain's blog

Setup a local registry for Kubernetes

For testing purpose I'm using the Kubernetes cluster shipped with the Docker Desktop client (docker-for-desktop). I want to avoid to go through Docker Hub each time I want to build an image to run it in my Kubernetes local cluster.

To solve this problem I've setup a local registry that runs in the docker on my machine. I can push images to this local registry that are directly available from the Kubernetes cluster.

Declare the insecure registry

To be able to use a local non secure registry you have first to declare it.

# Getting your IP on a mac
$ MY_IP="$(ipconfig getifaddr en0)"
$ echo $MY_IP
xxx.x

You have to declare the MY_IP:5000 as an insecure registry in Docker client and apply and restart to change.

{{< figure src="/images/docker-local-registry_files/docker-registry.png" title="Docker settings" >}}

Start the registry

The registry documentation is available here.

# Start the registry
$ docker run -d -p 5000:5000 --name registry registry:2
# Test
$ curl -i $MY_IP:5000

HTTP/1.1 200 OK

Push an image in the registry

To be able to use it from Kubernetes you have first to push an image to it. For the example I'm reusing the image luksa/kubia from the great book Kubernetes in Action1.

# Tag the image with the registry
$ docker image tag luksa/kubia $MY_IP:5000/kubia
# Push
$ docker push $MY_IP:5000/kubia
# List the content
$ curl -X GET http://$MY_IP:5000/v2/_catalog

{"repositories":["kubia"]}

Use the image from the Kubernetes cluster

Now that the image is available in the local registry, I can use it from the Kubernetes cluster.

# Run the image
$ k run kubia --image=$MY_IP:5000/kubia --port=8080 --generator=run/v1
# Check what's going on
$ k describe pod
Events:
  Type    Reason                 Age   From                         Message
  ----    ------                 ----  ----                         -------
  Normal  Scheduled              44s   default-scheduler            Successfully assigned kubia-brwcb to docker-for-desktop
  Normal  SuccessfulMountVolume  43s   kubelet, docker-for-desktop  MountVolume.SetUp succeeded for volume "default-token-t5n42"
  Normal  Pulling                43s   kubelet, docker-for-desktop  pulling image "xxx.x:5000/kubia"
  Normal  Pulled                 43s   kubelet, docker-for-desktop  Successfully pulled image "xxx.x:5000/kubia"
  Normal  Created                42s   kubelet, docker-for-desktop  Created container
  Normal  Started                42s   kubelet, docker-for-desktop  Started container

# Testing if it works by exposing a http service
$ k expose rc kubia --type=LoadBalancer --name kubia-http
service "kubia-http" exposed
$ curl localhost:8080
You\`ve hit kubia-brwcb

# Cleaning things up
$ k delete rc kubia
replicationcontroller "kubia" deleted
$ k delete svc kubia-http
service "kubia-http" deleted

When you're done, you can simply stop the local registry.

# How to clean things up at the end
$ docker container stop registry && docker container rm -v registry

  1. Marko Luksa, Kubernetes in Action, (Manning, 2017)↩