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Pull, Inspect, and Run Containers

1. Setup: View Your Podman Storage Tree​

Before running containers, inspect where Podman stores its image and container data.

podman info --format 'Graph Root: {{.Store.GraphRoot}}, RunRoot: {{.Store.RunRoot}}'
tree -L 1 /scratch/$USER/.local/share/containers/storage/

You should see directories like overlay/, overlay-images/, and volumes/.

2. Pull an Official Image​

Lets find available images for Ubuntu. Specifically we want Ubuntu version 24.04, which has Long-Term Support. Notice we wil search the docker.io container registry.

Search for an Image on Dockerhub​

podman search docker.io/ubuntu

⚠️ Always try to pull official images where possible.

Search for an Official Image​

podman search --filter is-official=true docker.io/ubuntu

ℹ️ Notice that the official image is listed from library. The docker.io library lists official images

Searching tags with Skopeo​

There is no easy way to list all tags for a remote reposiutory using docker or podman directly. You can use the open-source container signing, manipulating, and inspecting tool skopeo.

skopeo list-tags docker://docker.io/library/ubuntu

ℹ️ At this point, most people would just navigate to the official Docker Hub and look at library/ubuntu to find available tags.

Finally, pulling the ubuntu:24.04 image.

podman pull docker.io/library/ubuntu:24.04

Now we can see the ubuntu:24.04 image locally. Alternatively use podman image ls.

podman images

ℹ️ Notice the relatively small size at ~80MB. This is a minimal image lacking many of the ammenities you may be used to including X11-utils.

3. Run Your First Container​

podman run -it --name firstdemo ubuntu:24.04

Once inside:

ls -a

Exit the container:

exit (or use Ctrl + D)

List containers:

podman container ls

ℹ️ Notice no containers are listed. Only running containers are shown with ls alone.

List containers (running and exited):

podman container ls -a

4. Try a Disposable Container​

podman run -it --rm --name tempdemo ubuntu:24.04

Exit again and verify the container is gone:

podman container ls -a

ℹ️ When running containers in batch environments, prefer to remove the container upon exiting unless debugging issues.

5. Reuse the Name​

podman will prevent you from overwriting an image without the --replace tag. If containers are created without a name, they will be given a random identifier that will be unique.

podman run -it --name firstdemo ubuntu:24.04

6. Authenticate with a Registry​

To push containers, youy will need to create a Docker Hub account and log in. Follow the instructions online, or in Container Registries

podman login docker.io

To use JLab’s registry (codecr):

podman login codecr.jlab.org
Username: <your_cue_id>
Password: <your_personal_access_token>

7. Push a container to your Namespace​

At this time, we have no container image to push! Continue through the getting started guide to the container build section.