Node components are installed and run on every node in the cluster. The components are responsible for all node run-time operations. Key components consist of:
- Kubelet: An agent that runs on each node to perform declarations or actions that are provided to the cluster-API. Kubelet performs node service functions to ensure that running pods are compliant with pod specifications (PodSpecs) and remain healthy. Kubelet does not manage containers or pods that were not created by Kubernetes.
- Kube-proxy: An instance of kube-proxy runs on every node of the cluster. The kube-proxy instance implements Kubernetes network services that run on the node. Kube-proxy also manages network connectivity and traffic route management based on host operating system packet filtering.
- Container run-time: The chosen container run-time engine (CRE) must be deployed on each node in a Kubernetes cluster. The CRE must comply with the Kubernetes Container Runtime Interface (CRI) specifications. OpenShift Container Platform defaults to the CRI-O container run-time and cannot be changed.