Kubernetes

Concepts

• Cluster is a group of machines running Kubernetes
• Master System is the system which contrals a cluster in with which one interacts. The master manages the cluster like load balancing, backup, replication, scheduling, ... The master system is the control plane consisting of the components:
  • kube-apiserver: this is an API server that exposes the Kubernetes API
  • etcd: key-value store of the cluster data
  • kube-scheduler: monitors pods
  • kube-controller-manager: runs controller processes
  • cloud-controller-manager: embeds cloud-specific control logic
• Nodes are the machines in a cluster. All nodes are called data plane. Each node has a container runtime such as Docker. A Node can host multiple Pods. A (worker) node comprises of:
  • kubelet: agent
  • kube-proxy: maintains network rules on nodes
  • container runtime
• Pods is a logical group of containers on a node.
• Pods are wrapped as a Kubnetes Service.
• Volumees are used to store data