How To Setup And Host A Private Docker Registry

Suppose you are working on your project and you have your own docker images and you want to host those docker images locally in office network then you need to host your own docker registry. Due to security reason, you may not use public docker repository like docker hub to store images for your organization.

So, in that case we will be having a node that will be a separate machine and we'll install docker registry there then we can do push pull images.

Docker private registry acts as a centralized store of custom images that you created for your application. We can easily push images to this private remote Docker registry and pull images from there whenever we needed.

This article demonstrates how to setup a basic private docker registry, and then later we will see how to configure HTTP Authentication, etc. Here we configure entire steps in latest Ubuntu 20.04 server.

Prerequisites

Ubuntu 20.04 server.
Docker & Docker-compose installed on Ubuntu server.

Here, we created Linux VM from Azure and Docker & Docker-compose up and running into this server. For Docker & Docker-compose installation on Linux m/c, we can follow my earlier article mentioned here - Setup Docker And Docker-compose On Linux VM

STEP 1 - Up and Running Docker & Docker-compose

To begin with the setup process first we need to make sure docker and docker- compose up and running in Linux VM.

STEP 2 - Configuring registry using docker-compose

Let’s create directories to keep the things organized and execute below commands step by step:

mkdir docker-registry
cd ~/docker-registry
mkdir volume
nano docker-compose.yml

docker-compose.yml

version: '3'

services:
  docker-registry:
    image: registry:2
    container_name: docker-registry
    restart: always
    ports:
    - "5000:5000"
    volumes:
      - ./volume:/var/lib/registry

  docker-registry-ui:
    image: konradkleine/docker-registry-frontend:v2
    container_name: docker-registry-ui
    restart: always
    ports:
    - "8080:80"
    environment:
        ENV_DOCKER_REGISTRY_HOST: docker-registry
        ENV_DOCKER_REGISTRY_PORT: 5000

You can exit and save using CTRL+X then Y and then ENTER.

At this point, we successfully created an entire configuration in docker compose yml file.

STEP 3 - Run docker-compose.yml

Let’s run the docker-compose using below command.

sudo docker-compose -f docker-compose.yml up -d

setup a basic private docker registry

To make sure that the registry is running, a simple docker ps should display the running containers.

STEP 4 - Allow Inbound port rule of Linux VM

Let’s allow port 8080 and 5000 from network security group.

setup a basic private docker registry

STEP 5 - Check docker-registry and docker-registry-ui in browser

Let’s check in browser. Here IP address is my VM public IP.

docker-registry

docker-registry-ui

STEP 5 - Push a Docker image to a remote private registry

We will pull hello-world image from docker hub and tag them and push to our own docker private registry. While creating tag, the image’s name needs to be prefixed with the registry’s URL with port included e.g., 20.204.80.36:5000/hello-world

sudo docker pull hello-world
sudo docker tag hello-world:latest 20.204.80.36:5000/hello-world
sudo docker push 20.204.80.36:5000/hello-world

setup a basic private docker registry

Ahh! Push images to the private registry is failing. Docker expects a secured channel over https. To configure unsecure registries, we will need to update a daemon.json file in docker configuration.

The push refers to repository [20.204.80.36:5000/hello-world]

Get "https://20.204.80.36:5000/v2/": http: server gave HTTP response to HTTPS client

On Linux m/c, let’s modify the .json file is located /etc/docker/daemon.json and insecure-registries with <<ip-address:port>>.

~/docker-registry$ sudo su
nano /etc/docker/daemon.json

{
  "insecure-registries" : ["20.204.80.36:5000"]
}

setup a basic private docker registry

exit

Let’s restart docker service now to take latest daemon configuration.

service docker stop
service docker start
sudo systemctl status docker

sudo docker push 20.204.80.36:5000/hello-world

setup a basic private docker registry

STEP 6 - Check Docker registry

The image is now safely stored on the Docker registry that we created.

setup a basic private docker registry

curl -X GET http://20.204.80.36:5000/v2/_catalog

setup a basic private docker registry

Awesome! Now Private docker registry is up and running. In the next article, we will see how to enforce HTTP Authentication to this repository.

Happy Learning!