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Kubernetes

  • https://kubernetes.io/docs/concepts/overview/components/

  • A Kubernetes cluster has two types of nodes (virtual machines)

  • Worker nodes: host the containers and the workloads
  • Master nodes: it's the controller
    • Manage, plan, schedule, monitor the worker nodes.
    • It receives the instructions from the config file.
    • Master node has the control plane components

Kubernetes Components

Control Plane (Master Nodes)

  • The control plane is deployed in the master nodes

  • Control plane components are deployed as static pods on each master node (that means there are 4 manifests in /etc/kubernetes/manifests)

  • etcd: k8s.gcr.io/etcd:3.4.13-0

  • kube-apiserver: k8s.gcr.io/kube-apiserver:v1.21.2
  • kube-controller-manager: k8s.gcr.io/kube-controller-manager:v1.21.2
  • kube-scheduler: k8s.gcr.io/kube-scheduler:v1.21.2

Data Plane (Worker Nodes)

  • These components are deployed in every cluster node (master or worker)

  • kubelet: deployed manually as a Service

  • kube-proxy: deployed as a DaemonSet
  • container runtime