Docker vs Podman: A Comprehensive Comparison for Modern Containerization

When choosing between Docker vs Podman for container management, developers should know the basic differences between these popular containerisation tools. Whilst Docker has long been the go-to solution, Podman has emerged as a compelling Docker alternative that addresses several limitations of the traditional Docker approach.

This article explores the key differences between Docker and Podman, helping you make an informed choice for your containerisation needs.

Understanding Container Engines

Before diving into the specifics, it’s crucial to understand what container engines do. Container engines handle everything about containers, from creating and running them to stopping/destroying them. They handle image management, networking, storage, and security isolation.

Docker pioneered the containerisation movement, introducing a client-server architecture with a central daemon process managing all container operations. Podman, developed by Red Hat, took a different approach by removing the daemon, resulting in a more secure and resource-efficient design.

Core Architectural Differences

The fundamental difference between Docker and Podman lies in their architectural approaches. Docker relies on a central daemon (dockerd) that runs with root privileges, managing all container operations. This daemon-based architecture has been both Docker’s strength and limitation.

Conversely, Podman employs a daemonless architecture where containers run directly through a more traditional fork-exec model. This design choice brings several advantages, particularly regarding security and resource management. Each container process in Podman can run with different user permissions, providing better isolation and security control.

Feature Comparison

Let’s examine the key features between Docker and Podman below:

Performance and Memory Efficiency: The Runtime Difference

One of Podman’s significant advantages is its use of crun as the default runtime. Compared to Docker’s runc, crun is written in C rather than Go, resulting in significantly lower memory usage and better performance. Here’s a simple benchmark that shows the elapsed time for running sequentially 100 containers. The containers run /bin/true, and the result is as follows:

As seen on containers/crun GitHub repository

This efficiency makes Podman particularly attractive for environments where resource optimisation is crucial, such as edge computing or systems running numerous containers.

Practical Example: Containerising a Node.js Application

Let’s examine how both tools handle building and running containers. We’ll use a basic Express server as our example:

// app.js
const express = require("express");
const app = express();
const port = 3000;

app.get("/", (req, res) => {
  res.send("Hello from a containerised Node.js app!");
});

app.listen(port, () => {
  console.log(`Server running on port ${port}`);
});

Here’s how we would containerise this application using both Docker and Podman. The Dockerfile is the same for both:

FROM node:22-slim

WORKDIR /app
COPY package*.json ./
RUN npm install
COPY . .

EXPOSE 3000
CMD ["node", "app.js"]

Building and Running with Docker:

# Build the image
docker build -t nodejs-app .

# Run the container
docker run -d -p 3000:3000 nodejs-app

Building and Running with Podman:

# Build the image
podman build -t nodejs-app .

# Run the container
podman run -d -p 3000:3000 nodejs-app

Notice how the commands are identical? This compatibility is intentional, making it easy for teams to transition from Docker to Podman, and from Podman to Kubernetes..

Systemd Integration: A Podman Advantage

One of Podman’s standout features is its native systemd integration. This feature enables you to manage containers as system services, enhancing lifecycle management and automating startup processes. Here’s an example of generating a systemd service file for our Node.js container:

podman generate systemd --name nodejs-app --files

This generates a service file that can be used to manage the container using standard systemd commands:

systemctl --user enable container-nodejs-app.service
systemctl --user start container-nodejs-app.service

There’s more to podman’s integration with systemd which I’ll cover in a different post.

Choosing Between Docker and Podman

The choice between Docker and Podman often depends on your specific requirements:

Choose Docker if:

• You don’t care about security and performance, you just want to run dev containers.
• You’re working with existing Docker Compose workflows that require Docker-specific Compose implementation.
• You require third-party tool integration which needs Docker-specific implementation (e.g. Kamal Deploy).
• You run Docker in production and want to use the same tool on your development machine/server.

Choose Podman if:

• Security is a primary concern (rootless containers).
• You need better resource efficiency.
• You’re working in a Kubernetes-centric environment.
• You need something that implements the OCI Compose Specification.
• You require systemd integration.
• You’re running containers at the scale where speed and memory efficiency matter.

Frequently Asked Questions About Docker and Podman

Can Podman completely replace Docker?

Podman can replace Docker in every use case I’ve encountered. It offers Docker-compatible commands and Podman Desktop has some, if not most, of the same features as Docker Desktop (e.g. Kubernetes set-up).

Is Podman more secure than Docker?

Podman’s rootless containers and daemonless architecture provide inherent security advantages over Docker’s traditional root-based daemon approach. Using the fork-exec model allows it to integrate well with the Linux kernel’s audit system. This way, the system logs exactly which user executed which containers.

Does Podman work with Docker Compose?

Yes, Podman supports the Compose spec which Docker Compose v2 implements. It does this through its podman-compose tool, allowing you to run existing Docker Compose files. If you use Podman Desktop and enable the Docker compatibility layer, then Docker’s docker-compose will be used instead of podman-compose.

Looking Forward

Docker and Podman continue to evolve, with Podman gaining particular momentum in enterprise environments. However, Docker’s extensive ecosystem and broad platform support ensure its continued relevance in the containerisation landscape.

Podman’s approach, which prioritizes rootless containers and resource efficiency, may become more relevant as container usage increases and supply chain security becomes more important. In Kubernetes, they’ve moved away from relying on Docker internals and now have a lighter alternative — CRI-O.

Remember that these tools aren’t mutually exclusive – many organisations use both, leveraging Docker’s developer-friendly features during development and Podman’s security and efficiency advantages in production environments. But I’d still argue that Podman is developer-friendly and I use it in development environments as well.

For more DevOps and Docker content subscribe at https://devopsforjavascript.dev