How to Install Podman on Debian 12

Introduction

Podman also known as Pod Manager is an open-source, daemonless container engine used to build, manage, and run Open Container Initiative (OCI) containers. Podman does not require a background daemon process making it suitable for environments such as production environments and CI/CD pipelines with improved resource usage.

This article explains how to install Podman on Debian 12 to build and run containerized applications on the server.

Prerequisites

Before you begin:

• Deploy a Debian 12 instance on Vultr.
• Create a new Vultr container registry to store your container images.
• Access the server using SSH as a non-root user with sudo privileges.

Install Podman

Podman is available in the default package repositories on Debian 12. Follow the steps below to install the latest Podman package using the APT package manager.

1. Update the server's package index.

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   $ sudo apt update

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2. Install Podman.

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   $ sudo apt install podman -y

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3. View the installed Podman version on your server.

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   $ sudo podman --version

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   Output:

   podman version 4.3.1

Manage the Podman System Service

Podmans uses two linked service profiles to run on a server, podman.service and podman.socket. podman.service enables access to Podman CLI and interaction with the Podman engine to run container management commands. podman.socket enables remote access to the application API, and integrates Podman with other container development tools. Follow the steps below to manage the Podman system service and enable the application to run on your server.

1. Enable the Podman system service to automatically start at boot.

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   $ sudo systemctl enable podman

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2. Start the Podman service.

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   $ sudo systemctl start podman

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3. View the podman.socket service status and verify that it's running.

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   $ sudo systemctl status podman.socket       

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   Output:

   ● podman.socket - Podman API Socket
        Loaded: loaded (/lib/systemd/system/podman.socket; enabled; preset: enabled)
        Active: active (listening) since Sun 2024-07-28 23:57:33 UTC; 4min 11s ago
      Triggers: ● podman.service
          Docs: man:podman-system-service(1)
        Listen: /run/podman/podman.sock (Stream)
        CGroup: /system.slice/podman.socket

4. View the podman.service status and verify that it's triggered by the podman.socket service.

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   $ sudo systemctl status podman.service

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   Output:

   ○ podman.service - Podman API Service
        Loaded: loaded (/lib/systemd/system/podman.service; enabled; preset: enabled)
        Active: inactive (dead) since Sun 2024-07-28 23:58:57 UTC; 2min 8s ago
      Duration: 5.037s
   TriggeredBy: ● podman.socket

5. Stop the Podman service.

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   $ sudo systemctl stop podman

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6. Restart the Podman service.

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   $ sudo systemctl restart podman

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Deploy Containerized Applications using Podman

Podman supports multiple image sources and registries to pull and run container images on your server. The /etc/containers/registries.conf configuration file includes registry information used by Podman to find container images. Podman uses default registries such as Docker Hub, quay.io, and registry.fedoraproject.org if the configuration file does not include any registry sources. Follow the steps below to deploy a containerized HTTP application using Podman using the default registry sources.

1. Pull the latest Apache HTTP server container image from Docker Hub using Podman CLI.

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   $ sudo podman pull docker.io/httpd

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   Your output should be similar to the one below when successful.

   //...
   Writing manifest to image destination
   Storing signatures
   b21577b6946fec9df0eaa3c21748d361bc19742ddb6185a4201baa4200fb35fa

2. List all Podman images and verify that the new container is available on your server.

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   $ sudo podman images

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   Output:

   REPOSITORY               TAG         IMAGE ID      CREATED       SIZE
   docker.io/library/httpd  latest      b21577b6946f  22 hours ago  152 MB

3. Deploy a new containerized application using the httpd image and expose it on the localhost port 8080.

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   $ sudo podman run -d --name hello-world -p 8080:80 docker.io/httpd

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4. List all active Podman container processes and verify that your application is active.

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   $ sudo podman ps

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   Your output should be similar to the one below.

   CONTAINER ID  IMAGE                           COMMAND           CREATED        STATUS            PORTS                 NAMES
   16f7b5fdab05  docker.io/library/httpd:latest  httpd-foreground  9 seconds ago  Up 9 seconds ago  0.0.0.0:8080->80/tcp  hello-world

5. Access the containerized application using your host port 8080 and verify that it's running.

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   $ curl http://localhost:8080

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   Output:

   <html><body><h1>It works!</h1></body></html>

6. Stop the container.

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   $ sudo podman stop hello-world

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Login to a Container Registry

Podman supports private and public registries such as the Vultr Container Registry to manage container images. Follow the steps below to create a new Python Flask application, build a container image, and store it in the Vultr Container Registry.

1. Access your Vultr Container Registry's management page.

2. Find your registry details within the overview tab, and copy the username and API key credentials to your clipboard.

   

3. Create a new environment variable to store your Vultr Container Registry URL. For example, https://ewr.vultrcr.com/demo.

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   $ export VULTR_CONTAINER_REGISTRY_NAME=https://ewr.vultrcr.com/demo

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4. Create another environment variable to store your Vultr container registry username. Replace example-user with your actual username.

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   $ export VULTR_CONTAINER_REGISTRY_USERNAME=example-user

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5. Create an environment variable to store your Vultr Container Registry API key. Replace registry-key with your actual API key.

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   $ export VULTR_CONTAINER_REGISTRY_API_KEY=registry-key

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6. Login to the Vultr Container Registry using Podman CLI and the environment variable values.

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   $ sudo podman login https://ewr.vultrcr.com/$VULTR_CONTAINER_REGISTRY_NAME -u $VULTR_CONTAINER_REGISTRY_USERNAME -p $VULTR_CONTAINER_REGISTRY_API_KEY

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   Your output should be similar to the one below when successful.

   Login Succeeded!

7. Create a new sample Python application file app.py.

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   $ sudo nano app.py

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8. Add the following contents to the file.

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   from flask import Flask
   app = Flask(__name__)
   
   @app.route("/")
   def hello():
       return "Greetings from Vultr"
   
   if __name__ == "__main__":
       app.run(host="0.0.0.0", port=5000)

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   Save and close the file.

   The above Python application initializes a new Flask web server that displays a Greetings from Vultr prompt when accessed using the application port 5000.

9. Create a new Dockerfile to containerize the Python application.

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   $ nano Dockerfile

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10. Add the following contents to the file:

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    FROM python:3.9-slim
    WORKDIR /app
    COPY . /app
    RUN pip install flask
    EXPOSE 5000
    CMD ["python", "app.py"]

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    Save and close the file.

    The above Dockerfile configuration builds a new Python Flask application container image with Python 3.9, installs Flask, and runs the application on port 5000.

11. Build the new container image with all files in your working directory.

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    $ sudo podman build -t my-python-app .

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    Your output should be similar to the one below when successful.

    //...
    Successfully tagged localhost/my-python-app:latest
    a49734b0f695c4c171b15b446c3734e43d27354006fa9bd756af1a78e33d5e47

12. View all container images on your server and verify that the new application image is available.

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    $ sudo podman images

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    Output:

    REPOSITORY                          TAG         IMAGE ID      CREATED        SIZE
    localhost/my-python-app             latest      a49734b0f695  9 minutes ago  765 MB
    docker.io/library/httpd             latest      b21577b6946f  22 hours ago   152 MB

13. Tag the httpd container image with your desired Vultr Container Registry repository name.

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    $ sudo podman tag my-python-app ewr.vultrcr.com/$VULTR_CONTAINER_REGISTRY_NAME/my-python-app:v1

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14. List all Podman images again and verify that the tagged image is available.

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    $ sudo podman images

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    Output:

    REPOSITORY                          TAG         IMAGE ID      CREATED        SIZE
    localhost/my-python-app             latest      a49734b0f695  9 minutes ago  765 MB
    ewr.vultrcr.com/demo/my-python-app  v1          a49734b0f695  9 minutes ago  765 MB
    docker.io/library/httpd             latest      b21577b6946f  22 hours ago   152 MB
    docker.io/library/python            3.9-slim    724a8ee22b0c  3 months ago   131 MB

15. Push the tagged image to your Vultr Container Registry.

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    $ sudo podman push ewr.vultrcr.com/$VULTR_CONTAINER_REGISTRY_NAME/my-python-app:v1

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    Output:

    //...
    Writing manifest to image destination
    Storing signatures

16. Access your Vultr Container Registry's management page, navigate to the Repositories tab, and verify that the new container image repository is available.

    

17. Deploy a new application using the container image from your Vultr Container Registry and forward the container port 5000 to your localhost port 5000.

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    $ sudo podman run -d --name hello-python -p 5000:5000 ewr.vultrcr.com/$VULTR_CONTAINER_REGISTRY_NAME/my-python-app:v1

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18. Access the localhost port 5000 using curl to verify that your containerized application is running correctly.

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    $ curl http://localhost:5000

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    Output:

    Greetings from Vultr

Conclusion

You have installed Podman on your Debian 12 server and managed the containerized application processes. Podman uses container processes similar to Docker and allows you to pull, run, and manage containers on your server. You can integrate Podman with other container development tools using the application API or use custom registries such as the Vultr Container Registry to store your container images. For more information, visit the official Podman documentation.