Introduction

Containers have transformed the way we build, ship, and run applications. For a long time, Docker has been the go-to solution for containerization, setting the standard across the industry. However, Podman has gained attention as a strong alternative, offering solutions to some of Docker’s architectural challenges.
In this blog, we’ll take a closer look at how Docker and Podman compare, explore their key differences, and walk through practical examples and real-world scenarios where each tool shines.

Table of Contents

• Overview: Docker vs Podman
• Architecture Differences
• Security Comparison
• Performance Analysis
• Hands-On: Basic Container Operations
• Migration from Docker to Podman
• Pros and Cons
• Conclusion

Overview: Docker vs Podman

Docker

• Created: 2013 by Solomon Hykes
• Architecture: Client-server model with Docker daemon
• Root Requirement: Requires root privileges
• OCI Compliance: Yes
• Company: Docker Inc.

Podman:

• Created: 2018 by Red Hat
• Architecture: Daemonless, fork-exec model
• Root Requirement: Supports rootless containers
• OCI Compliance: Yes
• Company: Red Hat (Open Source)

Architecture Differences

Docker Architecture:

• Client (docker CLI) → Docker Daemon → Containerd → RUNC → Container

Podman Architecture:

• Podman CLI → conmon → runc → Container

Key Difference:

1. Podman eliminates the need for a central daemon,
2. Podman is more secure and reduces the attack surface

Docker vs Podman

Security Comparison

Docker Security Concerns:

• Root Daemon: Docker daemon runs as root, creating security risks
• Single Point of Failure: If daemon is compromised, all containers are at risk
• Privileged Access: Requires sudo for most operations

Podman Security Advantages:

• Rootless Containers: Can run containers without root privileges
• No Daemon: Eliminates central point of attack
• User Namespace: Better isolation between host and container

Performance Analysis

Resource Usage:

• Docker: Higher memory footprint due to daemon
• Podman: Lower overhead, no persistent daemon

Startup Time:

• Docker: Faster for multiple containers (daemon already running)
• Podman: Slight overhead for first container, but no daemon startup cost

Hands-On: Basic Container Operations

Installing Podman:

• https://podman.io/docs/installation

Practical Example: Running a Web Server

With Docker:

# Run Nginx web server
docker run -d --name nginx-docker -p 8080:80 nginx:latest

# Check container status
docker ps

# View logs
docker logs nginx-docker

# Stop and remove
docker stop nginx-docker
docker rm nginx-docker

With Podman:

# Run Nginx web server
podman run -d --name nginx-podman -p 8081:80 nginx:latest

# Check container status
podman ps

# View logs
podman logs nginx-podman

# Stop and remove
podman stop nginx-podman
podman rm nginx-podman

Migration from Docker to Podman

• Alias Method (Quick Start):

# Add to your shell profile (.bashrc, .zshrc)
alias docker=podman
alias docker-compose=podman-compose

# Most Docker commands will work immediately
docker run hello-world  # Actually runs: podman run hello-world

• Dockerfile Compatibility:

# Most Dockerfiles work without modification:

# Build with Docker
docker build -t myapp .

# Build with Podman (same Dockerfile)
podman build -t myapp .

• Volume Migration:

# Export Docker volume
docker run --rm -v myvolume:/data -v $(pwd):/backup alpine \
  tar czf /backup/myvolume.tar.gz -C /data .

# Import to Podman
podman volume create myvolume
podman run --rm -v myvolume:/data -v $(pwd):/backup alpine \
  tar xzf /backup/myvolume.tar.gz -C /data

• Network Migration:

# Docker network
docker network create mynetwork

# Podman network
podman network create mynetwork

• Registry Migration:

# Pull from Docker Hub with Podman
podman pull docker.io/library/nginx

# Configure registries
echo 'unqualified-search-registries = ["docker.io"]' >> ~/.config/containers/registries.conf

Rootless Container Demo

# Run container as non-root user with Podman
podman run -it --rm alpine sh

# Inside container, check user
whoami  # Shows non-root user
id      # Shows user ID mapping

# Try to access host resources (should fail)
ls /proc/1/  # Limited access to host processes

Pros and Cons

Docker:

• Pros: Mature ecosystem – Extensive documentation – Large community – Docker Desktop GUI – Better Windows support – Established in enterprise
• Cons: Security concerns (root daemon) – Resource overhead – Single point of failure – Licensing changes – Requires Docker Desktop on macOS/Windows

Podman:

• Pros: Rootless containers – No daemon required – Better security model – Lower resource usage – Pod support (like Kubernetes) – Drop-in Docker replacement – Open source (Apache 2.0)
• Cons: Smaller community – Less mature ecosystem – Limited Windows support – Learning curve for Docker users – Some Docker Compose features missing

Conclusion

Both Docker and Podman are excellent containerization tools, each with distinct advantages:
Choose Docker if: You need mature ecosystem support – Working primarily on Windows/macOS – Require Docker Desktop features – Have existing Docker infrastructure – Need extensive third-party integrations
Choose Podman if: Security is a top priority – Working in Linux environments – Want rootless containers – Prefer open-source solutions – Need Kubernetes-like pod management – Want to reduce resource overhead

Key Takeaways

1. Compatibility: Podman provides excellent Docker compatibility
2. Security: Podman’s rootless architecture offers better security
3. Performance: Podman generally uses fewer resources
4. Ecosystem: Docker has a more mature ecosystem
5. Migration: Moving from Docker to Podman is relatively straightforward

Recommendations

• New Projects: Consider Podman for better security and performance
• Existing Projects: Docker migration can be done gradually
• Enterprise: Evaluate based on security requirements and existing infrastructure
• CI/CD: Podman offers advantages in pipeline security
• Development: Both tools work well for local development