Managing Container Images Using Podman and Skopeo on RHEL

1. Install podman on your RHEL server using yum. Alternatively, you can use Application Streams to install the container-tools package stream.

Note: If you use Application Streams, make sure you use the default stream.

2.We need to add 'localhost' to the empty line for [registries.insecure] in the /etc/containers/registries.conf file to specify our local container registry as an insecure registry. You'll need to do this using sudo.

1. A local container image registry has been pre-configured on your server. Before we can use it, we need to start it.
2. Run the script (registry.sh), provided in the cloud_user home directory. Run this script with sudo, as it requires root privilages.

The podman command comes with quite a bit of container management functionality included. Let's try the following:

1. Check your installed version of podman
2. Check out the help information on the podman command
3. Check out the help information on the podman image command
4. Use podman to search for the ubi:latest container images
5. Use podman to pull a copy of the registry.access.redhat.com/ubi8/ubi:latest container image
6. Compare the podman images command to the podman image list command
7. Compare the podman inspect ubi command to the podman image inspect ubi command
8. Add the myubi tag to the ubi:latest image
9. List our container images again
10. Log in to the local container inage registry at localhost:5000
11. Push the ubi:latest image in our local container image storage to the registry running on our lab server
    • Tag the ubi:latest image with the target of localhost:5000/ubi8/ubi
    • Push the image to localhost:5000/ubi8/ubi:latest
      • Use the --remove-signatures switch
12. Check the local registry's contents using curl -u cloud_user https://localhost:5000/v2/_catalog and the cloud_user password
13. Remove the myubi tag
14. List our container images again
15. Remove the image with no tags using the imageID
16. List our container images again
17. Use podman to search our local registry
18. Using podman, log out of the local container registry

Even though the podman command can be used to perform container image management, taking things to the next level requires skopeo. Let's try the following with skopeo:

1. Check your installed version of skopeo
2. Check out the help information on the skopeo command
3. Check out the help information on the skopeo inspect command
4. Use skopeo to log in to the local container image registry at localhost:5000
5. Use skopeo to copy a container image directly from docker://registry.access.redhat.com/ubi7/ubi:latest to our local registry (docker://localhost:5000/ubi7/ubi)
6. Check the local registry's contents using curl -u cloud_user https://localhost:5000/v2/_catalog and the cloud_user password
7. Use skopeo to sync a container image from docker://registry.access.redhat.com/ubi7/ubi:latest to our local registry (docker://localhost:5000/ubi7/ubi)
8. Use skopeo to inspect the ubi7 and ubi8 images on the local container registry
9. Use skopeo to list the tags on the ubi7 and ubi8 images on the local container registry
10. Use podman to search our local registry (localhost:5000/ubi)
11. Use skopeo to log out of the local container image registry at localhost:5000