ITGSS Certified DevOps Engineer Practice Test

Which feature of the Linux kernel isolates resource usage among a collection of processes?

1. Namespaces

2. cgroups

3. Threads

4. FIFOs

The correct answer is: cgroups

The correct answer focuses on cgroups (control groups), which are a vital feature of the Linux kernel designed to manage and isolate resource usage for a collection of processes. Cgroups allow system administrators to allocate resources—such as CPU time, system memory, network bandwidth, or combinations thereof—among user-defined groups of processes. This capability is particularly useful in scenarios where multi-tenant environments, like those seen in cloud computing, require strict resource allocation to ensure that one process does not monopolize shared resources, which could lead to performance degradation for others. By using cgroups, processes can have their resources limited, prioritized, or accounted for, thereby improving system efficiency and stability. In contrast, while namespaces are also a feature of the Linux kernel that isolate aspects of a process environment, such as process IDs, users, and network interfaces, they do not inherently manage or limit resource usage. Threads refer to the smallest unit of processing that can be scheduled by an operating system, and FIFOs are special file types used for inter-process communication. Neither threads nor FIFOs have the capability to isolate resource usage in the same manner that cgroups do.