With its Docker-compatible CLI and daemon-less architecture, Podman is an excellent choice for those looking to adopt a secure, scalable, and flexible approach to container management.
In modern software development, containerisation has become essential for building, testing, and deploying applications. Containers allow applications to run consistently across various computing environments, providing isolation, portability, and flexibility. This is achieved by packaging the code, runtime, system libraries, and dependencies into a container unit.
While Docker has long been the dominant containerisation tool, a powerful alternative has emerged: Podman. Short for Pod Manager, this tool is designed for managing OCI (Open Container Initiative)-compliant containers and images. As a Docker alternative, Podman offers more security, flexibility, and the ability to run containers without requiring a central daemon. This daemon-less architecture is one of its key differentiators, making Podman particularly appealing for users focused on security and user control.
Also, Podman maintains compatibility with Docker images and commands. The Podman CLI mimics the Docker CLI, meaning you can replace docker with podman in many commands. This makes transitioning from Docker to Podman seamless for developers.
Core features of Podman
Podman offers a range of features that provide container management flexibility, security, and scalability.
Daemon-less operation: Podman does not rely on a running daemon to manage containers. This improves system security since there’s no long-running root-privileged service required. Containers are started and managed directly by the user.
Rootless containers: A standout feature, Podman allows users to run containers without root access. By avoiding root permissions, security risks are minimised, making Podman ideal for multi-user environments or where untrusted containers are used.
Pod support: Podman extends beyond individual containers by introducing pods, which are groups of containers that share the same network and storage resources (Figure 1). This aligns with Kubernetes concepts, enabling a smoother transition from development to production environments using Kubernetes.
OCI-compliant image management: Podman supports OCI-compliant images—a key standard in the container ecosystem. This allows Podman to pull and run images from Docker Hub or any other OCI registry without compatibility issues.
Docker-like CLI: Podman’s CLI is almost identical to Docker’s. Commands like podman run, podman pull, and podman stop function just as they would in Docker. This makes migrating existing container workflows and scripts from Docker to Podman straightforward.
Podman usage and application
Setup and example: Getting started with Podman is easy. To install it on a Linux system, you can use the following commands depending on the distribution.
- For Fedora/CentOS/RHEL:
sudo dnf install podman
- For Ubuntu/Debian:
sudo apt install podman
Once installed, you can run a simple container like Alpine Linux using the following command:
podman run -it alpine /bin/sh
This will pull the Alpine image from the container registry and start a shell session.
Container and pod management
Running containers: Like Docker, Podman allows you to manage containers. You can list running containers, start/stop containers, and remove them using familiar commands.
- Listing containers:
podman ps -a
- Starting a container:
podman start <container_id>
- Stopping a container:
podman stop <container_id>
Pod management: With Podman, you can also create and manage pods, which are groups of containers that share the same resources. Here’s how to create a pod and run containers within it:
podman pod create --name mypod podman run -d --pod mypod nginx podman run -d --pod mypod redis
In this example, Nginx and Redis containers are created within the same pod, allowing them to share network and storage resources seamlessly.
Applications
Podman is widely used in various development, testing, and deployment phases. Some common use cases include:
Development and testing: Developers can run and test containers locally without root privileges. This reduces the risk of security breaches and ensures compatibility with production environments.
CI/CD pipelines: Podman can be integrated into CI/CD pipelines to automate the building, testing, and deployment of containers, providing flexibility for different stages of the DevOps lifecycle.
Kubernetes integration: Since Podman supports Kubernetes pods, it can be used in the development phase of Kubernetes applications. You can define your containers and pods locally using Podman and easily transition them to Kubernetes clusters.
Podman vs Docker
While Podman and Docker facilitate containerisation, they differ in architecture and security. Podman’s daemon-less and rootless design offers better security by running containers without requiring root access, reducing potential vulnerabilities. On the other hand, Docker relies on a central daemon that must run as root, presenting security risks but offering simplicity through a single management service (see Table 1).
Table 1: Podman and Docker: A comparison
| Feature | Podman | Docker |
| Architecture | Daemon-less | Centralised daemon |
| Rootless operation | Supports rootless containers | Requires root privileges for containers |
| Pod support | Native support for Kubernetes-style pods | No direct pod support |
| Security | Enhanced security with rootless containers | Daemon presents a security risk |
| Kubernetes integration | Native pod concept for a smooth transition | Requires additional setup |
| Compatibility | OCI-compliant and Docker-compatible CLI | Docker-specific commands |
Podman also aligns more closely with Kubernetes through its support for pods, a core feature of Kubernetes. However, Docker requires third-party tools like Docker Compose to manage multi-container setups. Docker’s well-established ecosystem, including Docker Hub and Docker Swarm, makes it the go-to solution for many container deployments.
In summary, Podman excels in security-conscious environments and Kubernetes-native workflows. In contrast, Docker’s maturity and ease of use make it ideal for developers seeking simplicity and extensive third-party integrations.
Podman is increasingly becoming a valuable tool for container management, offering unique advantages over Docker with respect to security, flexibility, and Kubernetes integration. Its rootless and daemon-less features will likely gain even more attention as organisations seek to improve security practices and avoid root-level vulnerabilities.
Whether you’re a developer, system administrator, or someone working in CI/CD, Podman is worth exploring for its cutting-edge capabilities in containerisation.
