Discovering Podman: A Lightweight Docker Alternative

In the world of containerized environments, Docker has long been the king, dominating discussions around container management. However, there's another powerful and increasingly popular tool on the block: Podman. Developed primarily by Red Hat, Podman is gaining traction for its daemonless structure, ease of use, and compatibility with Docker's command-line interface. In this blog, we will explore what Podman is, why it might be a better fit for some use cases, and how you can install it using different package managers like apt, dnf, and zypper.

What is Podman?

Podman (Pod Manager) is an open-source daemonless container engine that serves as a drop-in replacement for Docker. The most critical difference is that Podman runs containers without a central daemon and does so as a non-root user, enhancing the security by segregating privileges that could be harmful in Docker's traditional model. Additionally, Podman is built on a library known as libpod to manage pods, containers, container images, and container volumes.

Why Podman?

Here are a few reasons why users might choose Podman over Docker:

• No Daemon: Podman operates without the Docker daemon (dockerd) which means each container is run in its own instance of the container runtime, minimizing the risk of a complete system failure if the daemon fails.

• Rootless Containers: Podman enables ordinary users to execute and manage containers without requiring root privileges, enhancing the security aspects of container management.

• Pod Concept: Containers can easily be managed together in pods, which are groups of one or more containers that share the same network, IPC, and PID namespace, mimicking the design of Kubernetes pods.

• Compatibility with Docker: Podman can use Docker images directly and supports almost all the Docker CLI commands, making it easy for Docker users to transition.

Installing Podman

On Ubuntu/Debian systems (using apt):

First, update your package list to ensure you get the latest version of the software.

sudo apt-get update

Now install Podman:

sudo apt-get install -y podman

On Fedora/RHEL/CentOS systems (using dnf):

Podman is included in the default repository for Fedora, so you can directly install it using:

sudo dnf -y install podman

For RHEL and CentOS, make sure you have the @containers repository enabled:

sudo dnf -y install 'dnf-command(copr)'
sudo dnf -y copr enable rhcontainerbot/container-selinux
sudo dnf -y install podman

On openSUSE/SUSE systems (using zypper):

Ensure that your system is up-to-date:

sudo zypper refresh

Then, install Podman:

sudo zypper install -y podman

Verifying the Installation

After installation, you can verify that Podman is installed correctly by running:

podman --version

This command should return the version number of Podman installed on your system.

Getting Started With Podman

Here’s a simple example to test your setup. Run an Alpine container:

podman run -it --rm alpine /bin/sh

This command pulls the Alpine Linux image (if not already pulled), starts a new container from it, and gives you an interactive shell.

Conclusion

Podman offers an exciting alternative to Docker, emphasizing security and simplicity while maintaining high compatibility with Docker. Whether you're running a few containers locally or managing a large-scale production environment, Podman's daemonless and rootless features make it a compelling option. Why not try migrating a small project to Podman and experience its benefits firsthand?

Feel free to explore more about Podman’s advanced features and how it measures up against Docker in different scenarios. Happy containerizing!