Overview
A container runtime is a software component that manages the execution of containers. It handles tasks such as pulling container images from a registry, setting up the container's environment (namespaces, cgroups), and starting/stopping the container process.
Common Runtimes
- containerd: An industry-standard container runtime with an emphasis on simplicity, robustness, and portability.
- CRI-O: An implementation of the Kubernetes Container Runtime Interface (CRI) to enable using OCI (Open Container Initiative) compatible runtimes.
- Docker Engine: Historically the most popular runtime, though Kubernetes now interacts with it via containerd.
Role in Kubernetes
Kubernetes uses the Container Runtime Interface (CRI) to communicate with the chosen container runtime on each node.