containerd
also: container runtime, containerd daemon
A lightweight container runtime that manages the complete lifecycle of containers on Linux systems. It serves as the core component that pulls images, runs containers, and handles storage without requiring the full Docker daemon.
containerd is an industry-standard container runtime maintained by the Cloud Native Computing Foundation. It handles the low-level operations needed to run containers, including image management, container execution, and networking setup.
Unlike Docker (which wraps containerd with additional tools and a user-friendly interface), containerd is minimal and focused solely on runtime responsibilities. It communicates with the Linux kernel via runc, the actual container execution engine.
Example usage: instead of docker run ubuntu bash, you would use ctr run docker.io/library/ubuntu bash with containerd directly. Kubernetes and other orchestration platforms often use containerd as their runtime backend to avoid the overhead of the full Docker daemon.
containerd can be used standalone for container management in resource-constrained environments or as part of larger container ecosystems like Docker, Kubernetes, and containerd-based platforms.