What does containerization technology in Linux operating system consist of?

The containerization technology in Linux consists of several key components and mechanisms:

• Namespaces: Isolate processes by different aspects — filesystem (mount), processes (PID), network, user IDs, IPC, and others. This allows a container to see only its part of the system.

• Control Groups (cgroups): Limit and control resource usage (CPU, memory, disk, network) of a group of processes, ensuring isolation and resource management.

• Union Filesystems (OverlayFS, AUFS): Enable the creation of layered filesystems where the base image is immutable, and changes are written to the upper layer.

• Chroot (partially): Changes the root directory of a process, restricting access to the filesystem.

• Capabilities: Manage process rights, limiting their capabilities within the system.

• Network bridges and virtual interfaces: Provide isolation and configuration of network interactions between containers.

Together, these mechanisms allow the creation of isolated, lightweight environments — containers that operate independently on a single Linux kernel.