Control plane components are containerized: Components like the API server, scheduler, and controller manager are often deployed as containers.
Need for container runtime and management: These containerized control plane components require a container runtime (like Docker or containerd) and an agent to manage their lifecycle (like kubelet). The kubelet, along with other worker node components, provides this functionality.
Static Pods: Some critical control plane components are deployed as static pods. Static pods are managed directly by the kubelet on the same node where they reside, bypassing the API server. This ensures high availability of the control plane.
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A) While co-locating components can reduce latency, it's not the primary reason. The main reason is the dependency of containerized control plane components on the container runtime and management provided by worker node components.
B) The CRI defines how the kubelet interacts with container runtimes. It doesn't mandate that all components run on every node.
C) While static pods are relevant, this option doesn't fully explain the dependency of all control plane components (some are not static pods) on the worker node components for container management.