Exercises to learn Kubernetes

Prerequisites: kubectl and doctl.

Basic cluster creation in DigitalOcean with one node:

• doctl k8s cluster create mycluster --region ams3 --node-pool "name=mypool;count=1" create cluster
• doctl k8s cluster kubeconfig show mycluster >> ~/.kube/config copy cluster config
• kubectl get nodes: check if nodes are "Ready" Status

Concepts:

• nodes: is a worker machine. Each node contains the services necessary to run pods and is managed by the master components.
• namespaces: subclusters within a kube cluster
• labels: are key/value pairs that are attached to objects, such as pods. They are used to classify horizontally resources like with labels like apps or tier
• ReplicationController: maintain a stable set of replica Pods running at any given time.
• Deployments: declarative updates for pods
• pods: a group of one or more containers with shared specs on how to run them.
• services: exposes an applicaion running on a set of pods
  • load balancer: svc type to share requestes among several pods
  • node port: publish one port to another, external or internal to cluster
• Job: create one pod to run some tasks and ensure comlpetion.