What function do cgroups serve in Linux?

Cgroups, or control groups, play a critical role in the Linux operating system by allowing you to allocate and manage system resources such as CPU, memory, disk I/O, and network bandwidth for groups of processes. This functionality is essential for various use cases, including containerization, where processes running inside containers need to be isolated and have their resource usage controlled.

By using cgroups, system administrators can set limits on how much of a given resource a process can consume, prioritize processes, and ensure that no single process can monopolize system resources, thereby leading to better system stability and performance. This capability makes cgroups particularly valuable in environments like cloud computing and virtualization, where effective resource management is crucial.

The other options pertain to different functionalities within the Linux environment. Layered file systems, network communication management, and user ID definitions do not fall under the scope of what cgroups specifically handle.