kubelet
Per-node agent in Kubernetes. Communicates with apiserver, schedules containers via CRI (containerd, CRI-O), reports node + pod status, runs liveness/readiness probes.
Two main modes: Pod manifest from apiserver (common) or static pod manifests from /etc/kubernetes/manifests/ (for control-plane self-bootstrap). Manages local resources: cgroups, volumes (CSI), networking namespace. kubelet is often one of few components not run as container — runs as systemd service on the node. Configuration: KubeletConfiguration YAML, command-line flags (deprecated, many moved to config file). Debug: journalctl -u kubelet, kubectl get events.