Getting started

Basic terms: system parts
Kubernetes: the whole orchestration system (K8s "k-eights" or Kube for short)
Kubectl: CLI to configure Kubernetes and manage apps (using "cube control" official pronunciation)
Node: single server in the Kubernetes cluster
Kubelet: Kubernetes agent running on nodes
Control plane: set of containers that manage the cluster
Includes API server, scheduler, controller manager, etcd and more
Sometimes called the "master"
Installing Kubernetes locally
Kubernetes is a series of containers, CLI's and configurations
Many ways to install:
MacOS: Docker Desktop - Enable in Settings. Sets up everything inside Docker's existing Linux VM
Runs, configures Kubernetes Master containers
Manages kubectl install and certificates
Easily install, disable and remove from Docker GUI
Docker Toolbox on Windows - MiniKube. Uses VirtualBox to make Linux VM
Doesn't install kubectl, has to be installed separately
Your own Linux host or VM - MicroK8s. Installs Kubernetes right on the OS
Uses snap (rather apt or yum) for install.
Control MicroK8s service via microk8s. commands
kubectl accessible via microk8s.kubectl
Add an alias to your shell (.bash_profile): 
alias kubectl=microk8s.kubectl
Kuberneters in a Browser
​http://play-with-k8s.com​
katacoda.com 
Kubernetes Container Abstractions
Pod: one or more containers running together on one node. Basic unit of deployment. Containers are always in pods.
Controller: for creating / updating pods and other objects. Controllers manage pods, you almost never manage pods yourself. There are many types of Controllers, including Deployment, ReplicaSet, StatefulSet, DaemonSet, Job, CronJob, etc.
Service: network endpoint to connect to a pod.
Namespace: Filtered group of objects in cluster.
Secrets, ConfigMaps, etc.
Kubernetes Run, Create and Apply
Kubernetes is evolving, and so is the CLI
We get 3 ways to create pods from the kubectl CLI
kubectl run (changing to be only for pod creation)
kubectl create (create some resources via CLI or YAML)
kubectl apply (create / update anything via YAML)
Basic commands
kubectl version - shows a version of Client and Server
kubectl cluster-info
kubectl run my-nginx --image nginx - this will create a pod, replica set and a deployment
kubectl get pods - get current pods
kubectl get all - get all components
kubectl delete deployment my-nginx - delete named deployment
Scaling ReplicaSets
Start new deployment for one replica/pod
  kubectl run my-apache --image httpd
Scale deployment 
  kubectl scale deploy/my-apache --replicas 2
  kubectl scale deployment my-apache --replicas 2 (these are same commands)
Inspecting Deployments
Get logs
  kubectl logs deployment my-apache
Get logs from pods with a given label
  kubectl logs -l run=my-apache
Stern for Kubernetes can be used to tail logs from multiple pods (https://github.com/wercker/stern)
  brew install stern
  stern pod-query
Get pod info
  kubectl describe pod/<pod-id> (pod-id can be obtained with kubectl get pods)`
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Introduction

Exposing containers

Last modified 3yr ago