DockerHub is a service provided by Docker for finding and sharing container images with your team. It is the world’s largest repository of container images with an array of content sources including container community developers, open source projects and independent software vendors (ISV) building and distributing their code in containers. Users get access to free public repositories for storing and sharing images or can choose subscription plan for private repos.
One can easily pull the Docker Image from Dockerhub and run application in their environment flawlessly. But in case you want to setup a private registry, it is still possible to accomplish. Under this blog post, I will demonstrate how to build a private registry on Play with Docker in just 5 minutes.
Caution – Please note that Play with Docker platform is just for demo or training purpose. As the instance wipe away after 4 hours of limited time, it’s better to save your data before it gets wiped up.
Tested Infrastructure
| Platform | Number of Instance | Reading Time |
|---|---|---|
| Play with Docker | 1 | 5 min |
Pre-requisite
- Create an account with DockerHub
- Open PWD Platform on your browser
- Click on Add New Instance on the left side of the screen to bring up Alpine OS instance on the right side
Create a directory to permanently store images.
$ mkdir -p /opt/registry/data
Authenticate with DockerHub
$docker login
Start the registry container.
$ docker run -d \
-p 5000:5000 \
--name registry \
-v /opt/registry/data:/var/lib/registry \
--restart always \
registry:2
Display running containers.
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS
NAMES
3a056bf96c6d registry:2 "/entrypoint.sh /etc…" About an hour ago Up About an hour 0.0.0
.0:5000->5000/tcp registry
Pull Debian Stretch image from official repository.
$ docker pull debian:stretch
stretch: Pulling from library/debian
723254a2c089: Pull complete
Digest: sha256:0a5fcee6f52d5170f557ee2447d7a10a5bdcf715dd7f0250be0b678c556a501b
Status: Downloaded newer image for debian:stretch
Tag local Debian Stretch image with an additional tag – local repository address.
$ docker tag debian:stretch localhost:5000/debian:stretch
Push image to the local repository.
[node1] (local) root@192.168.0.23 ~
$ docker push localhost:5000/debian:stretch
The push refers to repository [localhost:5000/debian]
90d1009ce6fe: Pushed
stretch: digest: sha256:38236c068c393272ad02db100e09cac36a5465149e2924a035ee60d6c60c38fe size: 529
Remove local images.
[node1] (local) root@192.168.0.23 ~
$ docker image remove debian:stretch
Untagged: debian:stretch
Untagged: debian@sha256:df6ebd5e9c87d0d7381360209f3a05c62981b5c2a3ec94228da4082ba07c4f05
[node1] (local) root@192.168.0.23 ~
$ docker image remove localhost:5000/debian:stretch
Untagged: localhost:5000/debian:stretch
Untagged: localhost:5000/debian@sha256:38236c068c393272ad02db100e09cac36a5465149e2924a035ee60d6c60c38fe
Deleted: sha256:4879790bd60d439cfe39c063660eef7af525d5f6f1cbb701a14c7cfc11cbfcf7
Pull Debian Stretch image from local repository.
[node1] (local) root@192.168.0.23 ~
$ docker pull localhost:5000/debian:stretch
stretch: Pulling from debian
54f7e8ac135a: Pull complete
Digest: sha256:38236c068c393272ad02db100e09cac36a5465149e2924a035ee60d6c60c38fe
Status: Downloaded newer image for localhost:5000/debian:stretch
List stored images.
[node1] (local) root@192.168.0.23 ~
$ docker image ls
REPOSITORY TAG IMAGE ID CREATED SIZE
localhost:5000/debian stretch 4879790bd60d 12 days ago 101MB
registry 2 2e2f252f3c88 2 months ago 33.3MB
Shared local registry
Create a directory to permanently store images.
$ mkdir -p /srv/registry/data
Create a directory to permanently store certificates and authentication data.
$ mkdir -p /srv/registry/security
Store domain and intermediate certificates using /srv/registry/security/registry.crt file, private key using /srv/registry/security/registry.key file. Use valid certificate and do not waste time with self-signed one. This step is required do use basic authentication.
Install apache2-utils to use htpasswd utility.
[node1] (local) root@192.168.0.23 ~
$ apk add apache2-utils
OK: 302 MiB in 110 packages
Create initial username and password. The only supported password format is bcrypt.
$ : | sudo tee /srv/registry/security/htpasswd
[node1] (local) root@192.168.0.23 ~
$ echo "password" | sudo htpasswd -iB /srv/registry/security/htpasswd username
Adding password for user username
Adding password for user username
$(local) root@192.168.0.23 ~ $ cat /srv/registry/security/htpasswd username:$2y$05$q9R5FSNYpAppB4Vw/AGWb.RqMCGE8DmZ4q5HZC/1wC87oTWyvB9vy
Stop and Remove all old containers
$ docker stop $(docker ps -a -q)
3a056bf96c6d
$ docker rm -f $(docker ps -a -q)
3a056bf96c6d
Start the registry container.
[node1] (local) root@192.168.0.23 ~
$ docker run -d -p 443:5000 --name registry -v /srv/registry/data:/var/lib/registry -v /srv/registry/security:/etc/security -e REGISTRY_HTTP_TLS_CERTIFICATE=/etc/security/registry.crt -e REGISTRY_HTTP_TLS_KEY=/etc/security/registry.key -e REGISTRY_AUTH=htpasswd -e REGISTRY_AUTH_HTPASSWD_PATH=/etc/security/htpasswd -e REGISTRY_AUTH_HTPASSWD_REALM="Registry Realm" --restart always registry:2
e7755af8cbd70ea84ab77237a87cb97fd1abb18c7726fbc116c40f081d3b7098
Display running containers.
[node1] (local) root@192.168.0.23 ~
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
e7755af8cbd7 registry:2 "/entrypoint.sh /etc…" About a minute ago Restarting (1) 22 seconds ago registry
Pull Debian Stretch image from official repository.
$ docker pull debian:stretch
stretch: Pulling from library/debian
723254a2c089: Pull complete
Digest: sha256:0a5fcee6f52d5170f557ee2447d7a10a5bdcf715dd7f0250be0b678c556a501b
Status: Downloaded newer image for debian:stretch
Tag local Debian Stretch image with an additional tag – local repository address.
$ docker tag debian:stretch registry.collabnix.com/debian:stretch
This time you need to provide login credentials to use local repository.
$ docker push registry.collabnix.com/debian:stretch
e27a10675c56: Preparing
no basic auth credentials
$ docker pull registry.collabnix.com/debian:stretch
Error response from daemon: Get https://registry.collabnix.com/v2/debian/manifests/stretch: no basic auth credentials
Log in to the local registry.
$ docker login --username username registry.collabnix.com
Password: ********
Login Succeeded
Push image to the local repository.
$ docker push registry.collabnix.com/debian:stretch
The push refers to repository [registry.collabnix.com/debian]
e27a10675c56: Pushed
stretch: digest: sha256:02741df16aee1b81c4aaff4c48d75cc2c308bade918b22679df570c170feef7c size: 529
Remove local images.
$ docker image remove debian:stretch
Untagged: debian:stretch
Untagged: debian@sha256:0a5fcee6f52d5170f557ee2447d7a10a5bdcf715dd7f0250be0b678c556a501b
$ docker image remove registry.collabnix.com/debian:stretch
Untagged: registry.collabnix.com/debian:stretch
Untagged: registry.sl.collabnix.com/debian@sha256:02741df16aee1b81c4aaff4c48d75cc2c308bade918b22679df570c170feef7c
Deleted: sha256:da653cee0545dfbe3c1864ab3ce782805603356a9cc712acc7b3100d9932fa5e
Deleted: sha256:e27a10675c5656bafb7bfa9e4631e871499af0a5ddfda3cebc0ac401dfe19382
Pull Debian Stretch image from local repository.
$ docker pull registry.collabnix.com/debian:stretch
stretch: Pulling from debian
723254a2c089: Pull complete
Digest: sha256:02741df16aee1b81c4aaff4c48d75cc2c308bade918b22679df570c170feef7c
Status: Downloaded newer image for registry.collabnix.com/debian:stretch
List stored images.
$ docker image ls
REPOSITORY TAG IMAGE ID CREATED SIZE
registry 2 d1fd7d86a825 4 weeks ago 33.3MB
registry.collabnix.com/debian stretch da653cee0545 2 months ago 100MB
hello-world latest f2a91732366c 2 months ago 
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