What is Podman and How Does it Compare to Docker?

Docker has long been the dominant container engine, but it’s not the only one. After all, Kubernetes moved away from Docker several years ago to a different engine. An alternative to Docker for running containers on your local machine has been gaining traction in recent years: Podman. Podman is an open-source container engine developed by Red Hat engineers along with community support that offers a daemonless, secure, and efficient way to manage containers, providing a compelling alternative to Docker.

This article will provide a detailed overview of Podman, its key differences from Docker, and a command comparison to help developers transition seamlessly between the two.

What is Podman?

Podman (short for Pod Manager) is an open-source container management tool designed to develop, manage, and run OCI (Open Container Initiative) containers and container images. Unlike Docker, Podman does not require a background daemon process, making it more lightweight, secure, and robust.

Key Features of Podman

• Daemonless architecture – No root-running background daemon.
• Rootless execution – Allows running containers without root privileges.
• Native pod support – Inspired by Kubernetes pods.
• Docker-compatible CLI – Uses similar commands to Docker.
• Systemd integration – Easily manages containers as system services.

Podman vs Docker: Key Differences

While Docker and Podman share many functionalities, they have some fundamental architectural and operational differences:

1. Daemonless vs Daemon-based Architecture

Docker’s Daemon-based Model

Docker operates using a client-server model, where:

• The Docker CLI (Command Line Interface) interacts with the Docker daemon (dockerd).
• The daemon is responsible for managing images, containers, networking, and storage.
• This daemon runs as a privileged root process, making it a single point of failure (if the daemon crashes, all running containers are affected).

Podman’s Daemonless Model

Podman, on the other hand, does not rely on a daemon:

• It follows the fork-exec model, where each container runs as an independent child process.
• Since there’s no central daemon, Podman does not have a single point of failure.
• The system remains more stable and secure, as containers can be managed independently.

2. Rootless Execution and Security

Security is a significant advantage of Podman over Docker.

Docker: Root Process Execution

• By default, the Docker daemon runs as root, meaning all containers it creates also have root privileges.
• This poses security risks: if a vulnerability is exploited, attackers can gain root access to the entire system.

Podman: Rootless Containers

• Podman allows running containers as a non-root user, minimizing security risks.
• Rootless containers improve security by restricting access to system resources.
• Even if a container is compromised, the attacker only has user-level access, not root access.

3. Kubernetes and Pod Integration

Podman integrates seamlessly with Kubernetes, making it an excellent tool for container orchestration.

Docker: Single-container Focus

• Docker primarily focuses on managing individual containers.
• While it supports Kubernetes via docker-compose and other tools, it is not inherently designed to manage multiple containers as a group.

Podman: Native Pod Support

• Podman introduces Pods, similar to Kubernetes Pods.
• A pod in Podman is a collection of one or more containers sharing the same network and storage.
• Users can create pods locally and then export Kubernetes manifests for easy deployment.

Example: Creating a Pod with Podman

podman pod create --name mypod
podman run -dt --pod mypod nginx
podman run -dt --pod mypod redis

This allows seamless local development and testing before deploying to a Kubernetes cluster.

4. Docker CLI Compatibility

Podman was designed to be fully compatible with Docker’s command-line interface (CLI). Developers familiar with Docker commands can use Podman as a drop-in replacement.

For instance:

• Docker command: docker run -d nginx
• Podman equivalent: podman run -d nginx

Podman even provides a Docker alias for convenience:

alias docker=podman

This allows users to run Docker commands without modification.

Command Comparison: Podman vs Docker

Here’s a side-by-side comparison of commonly used commands in Docker and Podman:

Generate Kubernetes YAML with Podman

One of Podman’s most useful features is the ability to automatically generate Kubernetes YAML deployment files. This allows users to test locally and then easily export their containers to Kubernetes.

Step 1: Creat a Pod

podman pod create --name mypod

Step 2: Run Containers in the Pod

podman run -dt --pod mypod --name web nginx
podman run -dt --pod mypod --name redis redis

Step 3: Generate the Kubernetes YAML

podman generate kube mypod > mypod-deployment.yml

This command exports the Pod and its associated containers into a Kubernetes YAML manifest file (mypod-deployment.yml).

apiVersion: v1
kind: Pod
metadata:
  name: mypod
spec:
  containers:
  - name: web
    image: nginx
    ports:
    - containerPort: 80
  - name: redis
    image: redis

This file can be used directly in a Kubernetes cluster, allowing for easy testing and migration.

Step 4: Apply the YAML to Kubernetes

Once the file is generated, you can apply it directly to a Kubernetes cluster using kubectl:

kubectl apply -f mypod-deployment.yml

This makes transitioning from local Podman development to Kubernetes extremely easy.

Why is This Useful?

This feature makes Podman an excellent tool for Kubernetes developers, allowing them to move from local development to production Kubernetes clusters with minimal effort.

✅ Simplifies Kubernetes Development – Local development with Podman can easily be migrated to a Kubernetes cluster.
✅ No Manual YAML Writing – Automates the process of generating deployment files.
✅ Bridges Local and Cloud Deployments – Developers can create a pod locally, test it, then deploy to Kubernetes without rewriting configurations.

Why Choose Podman Over Docker?

Podman is a strong alternative to Docker, particularly for users who prioritize security, stability, and Kubernetes integration.

Advantages of Podman

✅ No Daemon (Daemonless Architecture) → Eliminates single points of failure.
✅ Rootless Mode → Enhances security and minimizes attack risks.
✅ Native Pod Support → Aligns with Kubernetes’ pod-based architecture.
✅ Docker CLI Compatibility → Easy transition from Docker.
✅ Systemd Integration → Manage containers as system services.

When to Use Docker Instead?

🔹 If you require Docker Compose (though Podman now has podman-compose).
🔹 If you rely on Docker Swarm for orchestration.
🔹 If you already have an established Docker workflow and security isn’t a major concern.

Conclusion

Podman is a modern, secure, and efficient alternative to Docker, offering features like rootless execution, daemonless architecture, and Kubernetes-native pods. With strong CLI compatibility and enhanced security, Podman is a great choice for developers seeking an open-source, robust container engine.

For users transitioning from Docker, the command similarities ensure a smooth learning curve, while advanced features like pod management provide additional benefits.

Get Started with Podman

If you’re working in cloud-native development, Kubernetes environments, or security-conscious deployments, Podman is worth considering over Docker.

Would you like to try Podman? Install it today with:

sudo dnf install podman  # (For Fedora, RHEL, CentOS)
sudo apt install podman  # (For Debian, Ubuntu)
brew install podman      # (For macOS)

Let me know your thoughts in the comments below! 🚀

Original Article Source: What is Podman and How Does it Compare to Docker? written by Chris Pietschmann (If you're reading this somewhere other than Build5Nines.com, it was republished without permission.)