Configure a Docker Client with the Harbor Registry Certificate

To work with container images in a registry using Docker, you add the registry certificate to the Docker client. The certificate is used to authenticate Docker during registry login.

Configure your Docker client to interact with a container registry, such as the Harbor Registry or Docker Hub. This example assumes you are using the Harbor Supervisor Service.

Prerequisites

This task assumes that you are using a Linux host (Ubuntu) on which the Docker daemon is installed. To install the Docker Engine (daemon) on an Ubuntu host, see https://docs.docker.com/engine/install/ubuntu/.

To verify that Docker is installed and that you can pull images from the Docker hub, run the following command:

docker run hello-world

Expected result:

Hello from Docker!
This message shows that your installation appears to be working correctly.

Note: These instructions are verified using Ubuntu 20.04 and Docker 19.03.

Procedure

Log in to Harbor Registry.
Select Administration > Configuration > Registry Root Certificate.
Click Download to download the Harbor Registry certificate named ca.crt.

Note: If necessary, change the name of the certificate to ca.crt.
Securely copy the ca.crt file to your Docker host client.
On the Docker host, create a directory path for the private registry using the Harbor IP address.
```
/etc/docker/certs.d/IP-address-or-FQDN-of-harbor/
```
For example:
```
mkdir /etc/docker/certs.d/10.179.145.77
```

Move the ca.crt to this directory.

For example:

 mv ca.crt /etc/docker/certs.d/10.179.145.77/ca.crt

Restart the Docker daemon.
```
sudo systemctl restart docker.service
```

docker login https://10.179.145.77

You should see the following message:

WARNING! Your password will be stored unencrypted in /home/ubuntu/.docker/config.json.
Configure a credential helper to remove this warning. See
https://docs.docker.com/engine/reference/commandline/login/#credentials-store

Login Succeeded