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Step 1: Installation & Getting Started

Create and change into a directory where you would like to work.

Setup

OpenShift is Red Hat’s distribution of Kubernetes

minikube and minishift are essentially equivalent and will be used for the demonstrations/examples below.

Prerequisites

  • Docker for Mac/Windows

  • git

  • JDK

  • Apache Maven (compilation of Java projects)

  • curl, tar

  • minikube and/or minishift will be downloaded below

  • kubectl and/or oc will be downloaded below

Downloads

Download & Install Kubernetes CLI

$ curl -LO https://storage.googleapis.com/kubernetes-release/release/v1.10.1/bin/darwin/amd64/kubectl
$ chmod +x kubectl
# or
brew install kubectl

Other instructions for finding and downloading the a kubectl https://kubernetes.io/docs/tasks/tools/install-kubectl/#install-kubectl

Download & Install Minikube Cluster

$ curl -Lo minikube https://storage.googleapis.com/minikube/releases/v0.28.1/minikube-darwin-amd64
$ chmod +x minikube
# or
brew cask install minikube
# if you don't have VirtualBox installed
brew cask install virtualbox

OR

Download & Install Minishift Cluster

$ curl -LO https://github.com/minishift/minishift/releases/download/v1.21.0/minishift-1.21.0-darwin-amd64.tgz
$ tar -xvf minishift-1.21.0-darwin-amd64.tgz

Note: "minikube" should be interchangeable with "minishift" in the instructions below, if there is a unique aspect then that will be called out.

Environment

#!/bin/bash

export MINIKUBE_HOME=/Users/burrsutter/minikube_0.28.1/bin;
export PATH=$MINIKUBE_HOME:$PATH
$ minikube version
minikube version: v0.28.
# or
$ minishift version
minishift v1.21.0+a8c8b37

Create the VM

#!/bin/bash

minikube config set memory 6144
minikube config set cpus 2 (1)
minikube config set vm-driver virtualbox #hyperkit
# minishift addon enable admin-user (2)
minikube start

  1. I use 2 cpus here because I have 6 core laptop. Keep this number at or below 50% of overall laptop resources. There is nothing in this series of exercises that is CPU intensive.

  2. Minishift is secured by default, this creates an cluster "admin" user

VirtualBox
Figure 1. VirtualBox UI

Check status, IP & Dashboard/Console

$ minikube config view
- cpus: 3
- memory: 8192
- vm-driver: virtualbox
$ minikube status
minikube: Running
cluster: Running
kubectl: Correctly Configured: pointing to minikube-vm at 192.168.99.103
$ minikube ip
192.168.99.103
$ minikube dashboard --url
http://192.168.99.103:30000
$ minikube dashboard
Minikube Dashboard
Figure 2. minikube dashboard
Minishift Dashboard
Figure 3. minishift dashboard

Check your kubectl CLI

$ kubectl config current-context
minikube

$ kubectl version
Client Version: version.Info{Major:"1", Minor:"10", GitVersion:"v1.10.1", GitCommit:"d4ab47518836c750f9949b9e0d387f20fb92260b", GitTreeState:"clean", BuildDate:"2018-04-12T14:26:04Z", GoVersion:"go1.9.3", Compiler:"gc", Platform:"darwin/amd64"}
Server Version: version.Info{Major:"1", Minor:"10", GitVersion:"v1.10.0", GitCommit:"fc32d2f3698e36b93322a3465f63a14e9f0eaead", GitTreeState:"clean", BuildDate:"2018-03-26T16:44:10Z", GoVersion:"go1.9.3", Compiler:"gc", Platform:"linux/amd64"}

and if needed, point kubectl back at minikube with "kubectl config use-context minikube"

Namespaces & Pods

$ kubectl get namespaces

$ kubectl get pod --all-namespaces

Configure Env for Docker

$ minikube docker-env
export DOCKER_TLS_VERIFY="1"
export DOCKER_HOST="tcp://192.168.99.103:2376"
export DOCKER_CERT_PATH="/Users/burrsutter/minikube_0.28.1/bin/.minikube/certs"
export DOCKER_API_VERSION="1.35"
# or
$ eval $(minikube docker-env)
# and
# eval $(minishift oc-env) (1)

  1. This command puts the "oc" CLI tool in your PATH

Using Docker CLI

$ docker ps
$ docker images

These commands should now be pulling from your minikube/minishift hosted docker daemon. You can turn off the Docker for Mac/Windows daemon to save memory.

Minikube/Minishift Happy?

$ minikube ssh (1)
$ free -h
$ df -h
$ top
$ ctrl-c
$ exit

  1. you can shell into your VM and check on resources

Hello World

Minishift is secured by default and requires you to login

$ oc login $(minishift ip):8443 -u admin -p admin

The "default" namespace should already be the current context, but setting it here to make it obvious

$ kubectl config set-context $(kubectl config current-context) --namespace=default

The command "kubectl run" is the fastest way to deploy a pod (think linux container). It is useful during development but NOT recommended for production

$ kubectl run hello-minikube --image=k8s.gcr.io/echoserver:1.10 --port=8080

It produces a Deployment

$ kubectl get deployments
NAME             DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
hello-minikube   1         1         1            1           7s

which produces a Pod

$ kubectl get pods
NAME                              READY     STATUS    RESTARTS   AGE
hello-minikube-7c77b68cff-2xcpp   1/1       Running   0          27s

# Tip, if you can not find your pod, perhaps it is in another namespace
$ kubectl get pods --all-namespaces

# and it can be fun to see what labels were applied to your pod
$ kubectl get pods --show-labels

You create a Service

$ kubectl expose deployment hello-minikube --type=NodePort
service "hello-minikube" exposed

and see that newly minted Service object

$ kubectl get service
NAME             TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
hello-minikube   NodePort    10.97.139.177   <none>        8080:32403/TCP   20s
kubernetes       ClusterIP   10.96.0.1       <none>        443/TCP           1h

You can find the Service’s URL

$ minikube service hello-minikube --url
http://192.168.99.103:32403
# and curl it
$ curl $(minikube service hello-minikube --url)

or just load up the URL in your favorite browser https://screencast.com/t/k5GVJlfg

The Deployment that was generated via your "kubectl run" commamnd actually has a bunch of interesting defaults

$ kubectl describe deployment hello-minikube
Name:                   hello-minikube
Namespace:              default
CreationTimestamp:      Sun, 29 Jul 2018 15:21:38 -0400
Labels:                 run=hello-minikube
Annotations:            deployment.kubernetes.io/revision=1
Selector:               run=hello-minikube
Replicas:               1 desired | 1 updated | 1 total | 1 available | 0 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  1 max unavailable, 1 max surge
Pod Template:
  Labels:  run=hello-minikube
  Containers:
   hello-minikube:
    Image:        k8s.gcr.io/echoserver:1.10
    Port:         8080/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Available      True    MinimumReplicasAvailable
  Progressing    True    NewReplicaSetAvailable
OldReplicaSets:  <none>
NewReplicaSet:   hello-minikube-7c77b68cff (1/1 replicas created)
Events:
  Type    Reason             Age   From                   Message
  ----    ------             ----  ----                   -------
  Normal  ScalingReplicaSet  5m    deployment-controller  Scaled up replica set hello-minikube-7c77b68cff to 1

but that is beyond the scope of simply getting started, just remember the "kubectl describe <object>" trick for future reference.

Another key tip to remember, is "get all" which is useful for seeing what other objects might be floating around

$ kubectl get all
# or with -n mynamespace
$ kubectl get all -n default

Clean up

$ kubectl delete service hello-minikube

$ kubectl delete deployment hello-minikube

And you will notice that the pod also terminates. In another terminal window, use the -w to watch as the pod changes state

$ kubectl get pods -w
NAME                              READY     STATUS    RESTARTS   AGE
hello-minikube-7c77b68cff-2xcpp   1/1       Running   0          8m
hello-minikube-7c77b68cff-2xcpp   1/1       Terminating   0         9m
hello-minikube-7c77b68cff-2xcpp   0/1       Terminating   0         9m

Use Ctrl-c to stop watching pods

You can shutdown the VM to save resources when not in use

$ minikube stop
# go about your business, come back later and
$ minikube start

and if you need to clean up the VM entirely

$ minikube delete

Your minikube configuration goes in a hidden directory at

$MINIKUBE_HOME/.minikube/machines/minikube/config.json

and your kubectl configuration goes in a different hidden directory at

$HOME/.kube/config

and if thing go really badly, you might need to wipe out those directories

$ rm -rf ~/.kube
$ rm -rf $MINIKUBE_HOME/.minikube