A Private Registry for Container Images enables you to work locally in a secured manner since you manage everything. With container registry, you build your container images on any machine, and push them to the local Container Registry with the Docker or Podman CLI. This guide will show you how to create a local Docker container image registry with Podman.

Podman is a daemonless container engine for developing, managing, and running OCI Containers on your Linux System. We have many guides on the installation of Podman.

Install Podman on CentOS 8

Install Podman on CentOS 7 / Fedora

Install Podman on Ubuntu

Install Podman on Debian

Once you have Podman installed, you can proceed to build your local Docker registry with it.

Step 1: Create domain for Docker registry

I’ll create a subdomain for container registry – registry.computingforgeeks.com and update DNS record for it.

Confirm the record is populated after you enable it.

$ dig A registry.computingforgeeks.com

; <<>> DiG 9.11.4-P2-RedHat-9.11.4-26.P2.el8 <<>> A registry.computingforgeeks.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 23567
;; flags: qr rd ra ad; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;registry.computingforgeeks.com.	IN	A

;; ANSWER SECTION:
registry.computingforgeeks.com.	300 IN	A	159.69.179.51

;; Query time: 14 msec
;; SERVER: 213.133.98.98#53(213.133.98.98)
;; WHEN: Thu Jan 16 11:25:14 CET 2020
;; MSG SIZE  rcvd: 75

Step 2: Create Insecure Registry

If you host your domain locally or want to use a registry without SSL certificates, you can do so though this is not recommended for production use.

Confirm that podman is installed:

$ podman version
Version:            1.4.2-stable2
RemoteAPI Version:  1
Go Version:         go1.12.8
OS/Arch:            linux/amd64

Create container data directory.

sudo mkdir -p /var/lib/registry

Create your insecure private registry like follows:

podman run --privileged -d \
  --name registry \
  -p 5000:5000 \
  -v /var/lib/registry:/var/lib/registry \
  --restart=always \
  registry:2
  • The registry contents will be store in /var/lib/containers/registry on the host system.

Here is my execution output:

Trying to pull docker.io/library/registry:2...Getting image source signatures
Copying blob c87736221ed0 done
Copying blob e8afc091c171 done
Copying blob 54d33bcb37f5 done
Copying blob b4541f6d3db6 done
Copying blob 1cc8e0bb44df done
Copying config f32a97de94 done
Writing manifest to image destination
Storing signatures
c99542d2802a85825cf75ecfa9ee34b5d4184b70f36acf110f75beaa4120b2aa

Check if registry container is running.

$ podman ps
CONTAINER ID  IMAGE                         COMMAND               CREATED        STATUS            PORTS                   NAMES
c99542d2802a  docker.io/library/registry:2  /entrypoint.sh /e...  3 minutes ago  Up 3 minutes ago  0.0.0.0:5000->5000/tcp  registry

Using Insecure Registry

By default, Docker / Podman client will try access registry over HTTPS. Since we have an HTTP registry, we need to make some changes to use insecure registry.

For Podman, edit the /etc/containers/registries.conf file and add insecure registry under the [registries.insecure] block.

$ sudo vi /etc/containers/registries.conf
registries = ['myregistry.local','registry.computingforgeeks.com:5000']

For Docker, edit /etc/sysconfig/docker and add –insecure-registry option.

OPTIONS='--insecure-registry registry.computingforgeeks.com:5000 --selinux-enabled .....' 

You need to restart docker service after making the change.

sudo systemctl restart docker

Test registry:

$ podman pull hello-world
$ podman  images
REPOSITORY                      TAG      IMAGE ID       CREATED         SIZE
docker.io/library/hello-world   latest   fce289e99eb9   12 months ago   6.14 kB
$ podman tag docker.io/library/hello-world registry.computingforgeeks.com:5000/hello-world
$ podman images
REPOSITORY                                        TAG      IMAGE ID       CREATED         SIZE
docker.io/library/hello-world                     latest   fce289e99eb9   12 months ago   6.14 kB
registry.computingforgeeks.com:5000/hello-world   latest   fce289e99eb9   12 months ago   6.14 kB

$ podman push registry.computingforgeeks.com:5000/hello-world
Getting image source signatures
Copying blob af0b15c8625b done
Copying config fce289e99e done
Writing manifest to image destination
Storing signatures

Check the registry contents on Registry server host.

$ ls /var/lib/registry/docker/registry/v2/repositories/
hello-world

You can tell pull the image on other hosts by running:

podman pull registry.computingforgeeks.com:5000/hello-world

Step 2: Create secure Registry with Let’s Encrypt certificate

Create container data directory.

sudo mkdir -p /var/lib/registry

Install certbot-auto tool which we’ll use to get a Let’s Encrypt SSL certificate for our registry.

wget https://dl.eff.org/certbot-auto
chmod a+x certbot-auto
sudo mv certbot-auto /usr/local/bin/certbot-auto
sudo firewall-cmd --add-service https --permanent
sudo firewall-cmd --reload

Get a Let’s Encrypt SSL certificate:

export DOMAIN="registry.computingforgeeks.com"
export EMAIL="[email protected]"
sudo /usr/local/bin/certbot-auto --standalone certonly -d $DOMAIN --preferred-challenges http --agree-tos -n -m $EMAIL --keep-until-expiring

  • Set your email address and domain name for registry

You’ll be shown the path where certificate and private keys are saved.

Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator standalone, Installer None
Obtaining a new certificate
Performing the following challenges:
http-01 challenge for registry.computingforgeeks.com
Waiting for verification...
Cleaning up challenges

IMPORTANT NOTES:
 - Congratulations! Your certificate and chain have been saved at:
   /etc/letsencrypt/live/registry.computingforgeeks.com/fullchain.pem
   Your key file has been saved at:
   /etc/letsencrypt/live/registry.computingforgeeks.com/privkey.pem
   Your cert will expire on 2020-04-15. To obtain a new or tweaked
   version of this certificate in the future, simply run certbot-auto
   again. To non-interactively renew *all* of your certificates, run
   "certbot-auto renew"
 - Your account credentials have been saved in your Certbot
   configuration directory at /etc/letsencrypt. You should make a
   secure backup of this folder now. This configuration directory will
   also contain certificates and private keys obtained by Certbot so
   making regular backups of this folder is ideal.
 - If you like Certbot, please consider supporting our work by:

   Donating to ISRG / Let's Encrypt:   https://letsencrypt.org/donate
   Donating to EFF:                    https://eff.org/donate-le

Set cron to autorenew:

# crontab -e
00 3 * * * /usr/local/bin/certbot-auto renew --quiet

Now create a secure Container registry.

export REG_DOMAIN="registry.computingforgeeks.com"
podman run --privileged -d \
  --name registry \
  -p 5000:5000 \
  -v /var/lib/registry:/var/lib/registry \
  -v /etc/letsencrypt/live/${REG_DOMAIN}/fullchain.pem:/certs/fullchain.pem \
  -v /etc/letsencrypt/live/${REG_DOMAIN}/privkey.pem:/certs/privkey.pem \
  -e REGISTRY_HTTP_TLS_CERTIFICATE=/certs/fullchain.pem \
  -e REGISTRY_HTTP_TLS_KEY=/certs/privkey.pem \
  registry:2 

Check if container is started successfully.

$ podman ps 
CONTAINER ID  IMAGE                         COMMAND               CREATED        STATUS            PORTS                   NAMES
d5ee3ead9d77  docker.io/library/registry:2  /entrypoint.sh /e...  7 seconds ago  Up 7 seconds ago  0.0.0.0:5000->5000/tcp  registry

Confirm it works:

$ podman pull nginx
$ podman images
REPOSITORY                TAG      IMAGE ID       CREATED      SIZE
docker.io/library/nginx   latest   c7460dfcab50   6 days ago   130 MB

$ podman tag docker.io/library/nginx registry.computingforgeeks.com:5000/nginx
$ podman images
REPOSITORY                                  TAG      IMAGE ID       CREATED      SIZE
docker.io/library/nginx                     latest   c7460dfcab50   6 days ago   130 MB
registry.computingforgeeks.com:5000/nginx   latest   c7460dfcab50   6 days ago   130 MB

$ podman push registry.computingforgeeks.com:5000/nginx
Getting image source signatures
Copying blob 17fde96446df done
Copying blob c26e88311e71 done
Copying blob 556c5fb0d91b done
Copying config c7460dfcab done
Writing manifest to image destination
Storing signatures

You can now use the registry across you infrastructure. If you want a more advanced registry, check:

Install Harbor Docker Image Registry on CentOS / Debian / Ubuntu

How To Setup Red Hat Quay Registry on CentOS / RHEL / Ubuntu

More on Podman:

How To Publish Docker Image to Docker Hub with Podman

How To run Docker Containers using Podman and Libpod