Meet Containerization: Apple’s Open Source Leap for Linux Containers on Mac

At WWDC25, Apple unveiled something big for developers: Containerization, an open source Swift framework designed to bring secure, private, and high-performance Linux containers to macOS. If you’re a developer who’s ever wanted a native-feeling, streamlined way to run containerized workloads on your Mac, this project is worth your attention.

Why Containers Matter

Containers have revolutionized how we build, test, and deploy software—especially on the server side. They allow developers to package applications alongside all their dependencies, ensuring consistency across environments. With containers, you can develop and test locally, knowing your app will behave the same way in production. Containers also provide strong isolation, keeping workloads separate from each other and from the host system, which is crucial for security and scalability.

The Challenge: Linux Containers on macOS

Running Linux containers on a Mac isn’t new, but until now, it typically meant spinning up a large virtual machine to host all your containers. This approach works, but it’s resource-intensive and can be less secure, as all containers share the same VM. Sharing files between your Mac and containers also required extra steps, and resource allocation wasn’t as granular as it could be.

Apple’s Solution: Containerization

Apple’s Containerization framework rethinks this model. Instead of running all containers in one big VM, each container gets its own lightweight virtual machine. This isolates workloads more effectively, improves security, and allows resources like CPU and memory to be allocated precisely as needed. Each container even gets its own dedicated IP address, making networking simpler and more performant.

Key Features

• Open Source Swift Framework: Containerization is built in Swift and open for the community to explore and contribute to.

• Powerful APIs: It provides APIs for image management, container execution, and a minimal, Swift-based init system called ‎⁠vminitd⁠.

• Block Device Filesystem: For fast access, container images are exposed as block devices with Linux-friendly filesystems (like EXT4), all manageable via Swift packages.

• Security & Privacy: Each container is isolated in its own VM, limiting access to files and directories on a per-container basis and reducing the attack surface by avoiding unnecessary utilities and libraries.

• Sub-second Startup: Despite the use of full VMs, containers start in just a few hundred milliseconds.

The Command Line Tool: ‎⁠container⁠

To make things even easier, Apple released a CLI tool called ‎⁠container⁠. With it, you can:

• Pull images: Download container images directly to your Mac.

• Run containers: Start an interactive shell or launch your app in a new container with just a few commands.

• Inspect environments: See the isolation in action—processes inside the container can’t see what’s running elsewhere, and you’re dropped into a real Linux environment.

Get Involved

Containerization is available on GitHub ↗, along with the CLI tool and example projects. Apple encourages developers to explore the code, contribute, and join the conversation.

Whether you’re building complex cloud-native apps or just want a better local dev experience on your Mac, Containerization represents a major step forward for Apple’s developer ecosystem. The future of containers on macOS just got a lot brighter.

Reference:

• https://developer.apple.com/videos/play/wwdc2025/346/