Nodes

Master is responsible for managing the cluster activities and communication with nodes.

A Node is a worker machine.

A node can be a virtual machine or physical machine

Following are the specific Node Requirements:

1. A Kubelet running

2. Container tool like Docker

3. Kube-proxy process running

4. Supervisord (restart components)

Recommended: K8s in production then have at least a 3 node cluster

Kubelet

• Communicates with API server to check if pods have been assigned to the nodes

• Execute pod containers via container engine

• Mounts and runs pod volumes and secrets

• Executes health checks for pod/node status

• Podspec : yaml file describing a pod

• Kube apiserver -> podspec -> kubelet -> pods mentioned are running and healthy

Kube-proxy

• Network proxy

• Runs on all worker nodes

• Modes:

  • User space

  • IPTables

  • IPvs (alpha feature)

• Watches API server for add/del of services