On which three technologies is containerization in Linux based?

Containerization in Linux is based on three key technologies:

1. Namespaces — isolate processes by creating separate namespaces for processes, network interfaces, file systems, and other resources. This allows containers to operate as if they are on a separate machine.

2. Control Groups (cgroups) — manage and limit resource usage (CPU, memory, disk, network) for a group of processes, ensuring control over the container's resource consumption.

3. Union File Systems (e.g., OverlayFS) — enable the creation of layered file systems where the base container image is immutable, and changes are written to the upper layer. This provides lightweight and efficient storage and startup of containers.

Together, these technologies provide isolation, resource management, and efficient storage, which form the basis of containerization in Linux.