Docker vs Rocket: What are the differences?

## Key Differences Between Docker and Rocket

Docker is a containerization platform that focuses on ease of use and portability, allowing developers to easily package, share, and run applications in isolated environments. On the other hand, Rocket, now known as Podman, is a containerization tool that emphasizes security, speed, and compatibility with different container runtimes. 

1. **Architecture**: Docker uses a client-server architecture, where the Docker client communicates with the Docker daemon to manage containers. Rocket, on the other hand, is designed as a standalone binary without any daemon running in the background, providing a simpler and potentially more secure approach. 

2. **Isolation**: Docker uses a containerd runtime, which provides a higher level of isolation by default, utilizing namespaces, cgroups, and capabilities to securely isolate containers. Rocket, on the other hand, relies on rkt as its runtime, which offers a minimal level of isolation with a focus on simplicity and speed. 

3. **Image Format**: Docker uses the Docker image format, which includes metadata, layers, and a manifest that describes how to run a specific container. Rocket utilizes the App Container (appc) spec, focusing on simplicity and composability by separating the image specification from the execution environment. 

4. **Orchestration**: Docker has built-in orchestration tools like Docker Swarm and Docker Compose for managing clusters of containers and defining multi-container applications. Rocket, on the other hand, does not have native orchestration tools but can be integrated with Kubernetes, making it suitable for more complex containerized environments. 

5. **Community Support**: Docker has a larger community and ecosystem with extensive documentation, plugins, and third-party tools that make it easy to adopt and integrate with existing workflows. Rocket, on the other hand, has a smaller but dedicated community that values security and compatibility with other container technologies. 

In Summary, Docker and Rocket (Podman) differ in terms of architecture, isolation mechanisms, image formats, orchestration capabilities, and community support, catering to different preferences and requirements in the containerization space.