How To Setup Docker Private Registry on CentOS 7/RHEL 7?

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Docker Private Registry?

Docker is one of the most emerging technology in today worlds. It is based on container and images. Images in docker are stored in repository which are used for creation of containers.

Well docker provide a public repository for storing our docker images knows as Docker Hub. You may push your images to docker hub for free, but the problem is, anything you upload is also public. And trust me as an origination or as private project developer you don’t want this to happen. So, Docker Private Registry comes in picture.

This article will guide you to set up and secure your own private Docker registry locally without using a docker image

Learn to setup Docker Private Registry without an docker container image. You may use this register to push or pull your own images.

Scenario:

192.168.56.101 push.kapendra.local push
192.168.56.102 pull.kapendra.local pull
192.168.56.104 registry.kapendra.local registry
Note: Firewalld service is down with SELinux disabled

All three servers have pre-install docker and running. If you don’t have docker service running, then visit my docker series

Let’s start

Step 1: Create Host Entry

To make Our push and pull node communicate with docker registry server, we need to create an entry in /etc/hosts file

Save this using :wq command

This step in only requited if your host machine can’t resolve hostname. In production this may not be required as record will get resolved through DNS server.

Note : Make this entry on all three nodes

Step 2: Install appropriate repository

To get the docker-distribution package you need to install epel repository or docker-ce repository. For this article I am using epel repo

Note : Run these commands on all three nodes

Step 3: Check for docker service.

To setup docker private registry , it very important to have a running docker service on that host. I suggest you check this service on all three. nodes

Note : Run this command on all three nodes

now rest of the command will need to run on registry node.

Step 4: Install Docker Registry

If you have CentOS 7.4 or above, then this package is available in epel repository. As told earlier I am using epel.

Step 5: Setup Docker registry

Default registry file is /etc/docker-distribution/registry/config.yml. You may change the root directory or port if you need to change.

From the default configuration file:

  • /var/lib/registry – location to store docker images, so make sure you make this partition on lvm and big one partition.
  • Port 5000 – bind port for registry service.

Step 6: Allow port 5000 in firewalld (optional)

This step is optional if you have SELinux enabled. I would suggest disable it else use this method

Step 7: Enable and start docker registry service

Now start the registry service with following command also enable for on boot start and don’t not forget to check the status.

Step 8: Add Insecure Registry to Docker Engine

As default docker uses https to connect to docker registry and we are not using any secure method, so we need to add our insecure registry. Follow below steps to add Insecure Registry to Docker Engine

.Note : Run these commands on all three nodes

Then restart Docker engine on three nodes

Test Our Setup

Step 9: Push Images To local registry

Now our docker registry is ready, so we can test it by pushing an image
So, on the push node run the flowing command.

Now tag this image as registry.kapendra.local:5000/busybox:latest.

Push the image to our created docker registry at registry.kapendra.local:5000/busybox:latest

sha256 hash show that image push was successful.

Note : To check this log on to registry server and see

Pushed images is stored under /var/lib/registry/docker/registry/v2/repositories directory on registry server.

Step 10: Pull Images From local registry

Now we have pushed our image to registry server so now we can pull this image on any server . so, let’s use our pull server to pull this image.

Check for pulled image

this brings us to the end of the setting up docker registry without https. In next article we will set up a GUI name Portainer for private docker hub registry.