What services are available on Kubernetes worker and master nodes, and what are they responsible for?

In a Kubernetes cluster, there are two main node roles: master node and worker node, and different services run on them.

Master nodes:

• kube-apiserver — the main API server through which interaction with the cluster occurs.
• etcd — a distributed key-value store that holds the cluster state.
• kube-scheduler — responsible for assigning pods to worker nodes, selecting suitable nodes for deployment.
• kube-controller-manager — runs controllers that monitor the cluster state and ensure its desired state (e.g., replication controller).
• cloud-controller-manager (if cloud infrastructure is used) — integration with cloud providers.

Worker nodes:

• kubelet — an agent that runs and monitors pods on the node, ensuring their lifecycle.
• kube-proxy — provides network routing and load balancing within the cluster.
• Container runtime (e.g., Docker, containerd) — directly runs containers.

Thus, master nodes manage the cluster state and make decisions, while worker nodes run containers and provide network interaction.