runc is a command-line utility for spawning and running containers on Linux systems according to the Open Container Initiative specification. It serves as a low-level container execution engine that interfaces directly with the host operating system to manage the lifecycle of isolated processes.
The tool functions as a Linux process containerizer, utilizing kernel features such as namespaces for process isolation and control groups for resource governance. It enforces security by restricting processes to specific directory trees and dropping unnecessary kernel privileges to minimize the attack surface of the host system.
By parsing standardized configuration files, the runtime translates high-level specifications into the system calls required to initialize and execute containerized workloads. It replaces the container initialization process with the target application, ensuring the container runs as the primary process on the host.