Private Docker Registry

Learn how to setup your own docker registry and push images for running algorithms in a C2D environment.
The document is intended for a production setup. The tutorial provides the steps to setup a private docker registry on the server for the following scenarios:
Allow registry access only to the C2D environment.
Anyone can pull the image from the registry but, only authenticated users will push images to the registry.
Setup 1: Allow registry access only to the C2D environment
To implement this use case, 1 domain will be required:
example.com: This domain will allow only image pull operations
Note: Please change the domain names to your application-specific domain names.
1.1 Prerequisites
Running docker environment on the linux server.
Docker compose is installed.
C2D environment is running.
The domain names is mapped to the server hosting the registry.
1.2 Generate certificates
# install certbot: https://certbot.eff.org/
sudo certbot certonly --standalone --cert-name example.com -d example.com
Note: Do check the access right of the files/directories where certificates are stored. Usually, they are at /etc/letsencrypt/.
1.3 Generate password file
Replace content in <> with appropriate content.
docker run \
  --entrypoint htpasswd \
  httpd:2 -Bbn <username> <password> > <path>/auth/htpasswd
1.4 Docker compose template file for registry
Copy the below yml content to docker-compose.yml file and replace content in <>.
version: '3'
​
services:
  registry:
    restart: always
    container_name: my-docker-registry
    image: registry:2
    ports:
      - 5050:5000
    environment:
      REGISTRY_AUTH: htpasswd
      REGISTRY_AUTH_HTPASSWD_PATH: /auth/htpasswd
      REGISTRY_AUTH_HTPASSWD_REALM: Registry Realm
      REGISTRY_HTTP_SECRET: <secret>
    volumes:
      - <path>/data:/var/lib/registry
      - <path>/auth:/auth
  nginx:
        image: nginx:latest
        container_name: nginx
        volumes:
            -  <path>/nginx/logs:/app/logs/
            -  nginx.conf:/etc/nginx/nginx.conf
            -  /etc/letsencrypt/:/etc/letsencrypt/
        ports:
            - 80:80
            - 443:443
        depends_on:
            - registry
1.5 Nginx configuration
Copy the below nginx configuration to a nginx.conf file.
events {}
http {
  access_log /app/logs/access.log;
  error_log /app/logs/error.log;
	
	server {
        client_max_body_size 4096M;
    		listen 80 default_server;
    		server_name _;
    		return 301 https://$host$request_uri;
	}
​
  server {
          # Allowed request size should be large enough to allow pull operations
          client_max_body_size 4096M;
          listen 443 ssl;
          server_name example.com;
          ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
          ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
          location / {
                  proxy_connect_timeout 75s;
                  proxy_pass http://registry-read-only:5000;
          }
  }
}
1.6 Create kubernetes secret in C2D server
Login into Compute-to-data enviroment and run the following command with appropriate credentials:
kubectl create secret docker-registry regcred --docker-server=example.com --docker-username=<username> --docker-password=<password> --docker-email=<email_id> -n ocean-compute
1.7 Update operator-engine configuration
Add PULL_SECRET property with value regcred in the operator.yml file of operator-engine configuration. For more detials on operator-engine properties refer this link​
Apply updated operator-engine configuration.
kubectl config set-context --current --namespace ocean-compute
kubectl apply  -f operator-engine/kubernetes/operator.yml
Steup 2: Allow anyonymous pull operations
To implement this use case, 2 domains will be required:
example.com: This domain will allow image push/pull operations only to the authenticated users.
readonly.example.com: This domain will allow only image pull operations
Note: Please change the domain names to your application-specific domain names.
2.1 Prerequisites
Running docker environment on the linux server.
Docker compose is installed.
2 domain names is mapped to the same server IP address.
2.2 Generate certificates
# install certbot: https://certbot.eff.org/
sudo certbot certonly --standalone --cert-name example.com -d example.com
sudo certbot certonly --standalone --cert-name readonly.example.com -d readonly.example.com
Note: Do check the access right of the files/directories where certificates are stored. Usually, they are at /etc/letsencrypt/.
2.3 Generate password file
Replace content in <> with appropriate content.
docker run \
  --entrypoint htpasswd \
  httpd:2 -Bbn <username> <password> > <path>/auth/htpasswd
2.4 Docker compose template file for registry
Copy the below yml content to docker-compose.yml file and replace content in <>. Here, we will be creating two services of the docker registry so that anyone can pull the images from the registry but, only authenticated users can push the images.
version: '3'
​
services:
  registry:
    restart: always
    container_name: my-docker-registry
    image: registry:2
    ports:
      - 5050:5000
    environment:
      REGISTRY_AUTH: htpasswd
      REGISTRY_AUTH_HTPASSWD_PATH: /auth/htpasswd
      REGISTRY_AUTH_HTPASSWD_REALM: Registry Realm
      REGISTRY_HTTP_SECRET: <secret>
    volumes:
      - <path>/data:/var/lib/registry
      - <path>/auth:/auth
  registry-read-only:
      restart: always
      container_name: my-registry-read-only
      image: registry:2
      read_only: true
      ports:
        - 5051:5000
      environment:
        REGISTRY_HTTP_SECRET: ${REGISTRY_HTTP_SECRET}
      volumes:
        - <path>/docker-registry/data:/var/lib/registry:ro
      depends_on:
        - registry
  nginx:
        image: nginx:latest
        container_name: nginx
        volumes:
            -  <path>/nginx/logs:/app/logs/
            -  nginx.conf:/etc/nginx/nginx.conf
            -  /etc/letsencrypt/:/etc/letsencrypt/
        ports:
            - 80:80
            - 443:443
        depends_on:
            - registry-read-only
2.5 Nginx configuration
Copy the below nginx configuration to a nginx.conf file.
events {}
http {
  access_log /app/logs/access.log;
  error_log /app/logs/error.log;
	
	server {
        client_max_body_size 4096M;
    		listen 80 default_server;
    		server_name _;
    		return 301 https://$host$request_uri;
	}
​
  server {
           # Allowed request size should be large enough to allow push operations
           client_max_body_size 4096M;
           listen 443 ssl;
           server_name readonly.example.com;
           ssl_certificate /etc/letsencrypt/live/readonly.example.com/fullchain.pem;
           ssl_certificate_key /etc/letsencrypt/live/readonly.example.com/privkey.pem;
           location / {
                   proxy_connect_timeout 75s;
                   proxy_pass http://registry:5000;
           }
  }
​
  server {
          # Allowed request size should be large enough to allow pull operations
          client_max_body_size 4096M;
          listen 443 ssl;
          server_name example.com;
          ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
          ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
          location / {
                  proxy_connect_timeout 75s;
                  proxy_pass http://registry-read-only:5000;
          }
  }
}
Start the registry
docker-compose -f docker-compose.yml up 
Working with registry
Login to registry
docker login example.com -u <username> -p <password>
Build and push an image to the registry
Use the commands below to build an image from a Dockerfile and push it to your private registry.
docker build . -t example.com/my-algo:latest
docker image push example.com/my-algo:latest
List images in the registry
curl -X GET -u <username>:<password> https://example.com/v2/_catalog
Pull an image from the registry
Use the commands below to build an image from a Dockerfile and push it to your private registry.
# requires login
docker image pull example.com/my-algo:latest
​
# allows anonymous pull if 2nd setup scenario is implemented
docker image pull readonly.example.com/my-algo:latest
Next step
You can publish an algorithm asset with the metadata containing registry URL, image, and tag information to enable users to run C2D jobs.
Further references
​Setup Compute-to-Data environment​
​Writing algorithms​
​C2D example​
Writing Algorithms
User defined parameters
Last modified 9mo ago