Introduction

Podman is a containerization tool like Docker that enables users to efficiently oversee and execute containers. Positioned as a viable alternative to Docker, Podman is particularly favoured in environments prioritizing heightened security, enhanced flexibility, and seamless integration with the Kubernetes ecosystem. This article delves into a comprehensive examination of the parallels and differentiating aspects between these two tools, aiming to provide insights into the question:


"Does switching from Docker to Podman yield significant advantages?"


Differences Between Podman And Docker

Let's learn some of the key differences between Podman and Docker:

  1. Podman Architecture: Podman does not require a daemon to run containers, unlike Docker, which relies on the Docker daemon (dockerd). Instead, Podman uses a daemonless architecture, where containers are managed directly by the user or by the system. This can improve security and resource utilization.
  2. Rootless Container Support: Podman supports running containers as non-root users, which enhances security by reducing the potential attack surface. Docker also supports rootless containers, but it's more deeply integrated into Podman's architecture.
  3. Integration with Kubernetes: Podman is designed to be more compatible with Kubernetes workflows. It supports generating Kubernetes YAML directly from Podman commands, making transitioning between local development and production environments easier.
  4. CLI Compatibility: Podman aims to maintain compatibility with the Docker CLI, meaning many Docker commands can be used with Podman without modification. This can make it easier for users familiar with Docker to transition to Podman.
  5. Integration with Buildah and Skopeo: Podman integrates with Buildah and Skopeo, tools for building and managing container images. This allows for more flexibility in the container-building process and can be beneficial for complex build scenarios. Please note that Buildah is a more advanced container image creation tool, and Podman contains a subset of Buildah features. Both run on similar code.

Podman's Architecture

Podman's architecture differs significantly from Docker's in that it operates in a daemonless mode. Here's a breakdown of how Podman's architecture works:

  1. Daemonless Architecture: Unlike Docker, which relies on a daemon process (dockerd) to manage containers, Podman operates without a central daemon. This means no single point of failure or a privileged process is running continuously in the background. Instead, Podman interacts directly with the container runtime.
  2. Libpod Library: Podman is built on top of the Libpod library, which provides a set of APIs for managing containers and pods. These APIs allow users to perform container-related tasks programmatically without needing to interact directly with the command-line interface.
  3. Container Management: When a user runs a Podman command to create, start, stop, or manage containers, Podman directly interacts with the container runtime (usually provided by OCI-compliant runtimes like runcand other necessary components, such as Cgroups, namespaces, and SELinux.)
  4. Integration with Systemd: Podman can be integrated with Systemd, the Linux system and service manager to manage containers as systemd units. This allows containers to be started, stopped, and managed like any other system service, providing greater flexibility in managing containerized applications.
  5. Network and Storage Management: Podman integrates with the host's networking and storage systems, leveraging standard Linux networking tools and storage drivers. This allows for seamless integration with existing network configurations and storage solutions.
  6. CLI Compatibility: Podman maintains compatibility with the Docker CLI, meaning many Docker commands can be used with Podman without modification. This makes it easier for users familiar with Docker to transition to Podman without learning new commands.

Installing and Using Podman

Installation

For Mac Systems, using Brew

brew install podman

The Debian and Fedora/Redhat package repositories already contain the Podman packages, albeit some of them are a bit older. For the latest packages, you must add the official PPA for Debian and Copr for Redhat/Fedora.

On Debian-based Linux derivatives

apt update && apt install podman

On Fedora/Redhat-based Linux derivatives

dnf install podman

More install instructions are listed in this documentation.

Using Podman

Podman is compatible with Docker and is simple to use. If you are familiar with Docker, you already know how to create and run Docker images. The same principles can be applied here. Just replace Docker with the word Podman, and they will work. All things are the same except the way we call images from Dockerhub. You see Docker by default prefixes docker.io/v1/image-name when we call for an image, but when using Podman, we specifically have to mention the image's registry URL along with the Docker Image's name to pull images from Docker Hub. No login is required to pull images that are publicly available docker images. Let's try it out!

Pulling An Image

podman pull docker.io/library/ubuntu:latest

Running An Image

podman run -it docker.io/library/ubuntu:latest

Building A Docker Image

podman build -t my-ubuntu .
FROM ubuntu:latest
CMD "echo", "built with podman"

Dockerfile

Logging Into A Docker Registry

podman login registry-url username password

Pushing Docker Image

podman push my-ubuntu docker.io/<your-username>/my-ubuntu:latest

Does Switching From Docker to Podman Yield Significant Advantages?

The decision to transition from Docker to Podman hinges on the unique requirements and use cases of an organization. Podman presents notable advantages in security, compatibility with Kubernetes, and increased flexibility. However, Docker maintains a substantial user base and robust ecosystem support. Prior to making a definitive choice, a thorough evaluation of organizational needs is imperative, taking into account factors like compatibility with current tools and workflows. A balanced consideration of these aspects ensures an informed decision aligned with the organization's overarching goals and objectives.

Conclusion

In this blog, we learned about Podman and its architecture and discussed whether switching from Docker to Podman is feasible.

Please comment below if you have any queries. I periodically try to update my articles to ensure legibility.