[Hands-on] Kubernetes | Nov 18, 2017

ORACLE MONTHLY
MEETUP
Date: 2017-11-18, Saturday, 12:30~17:00
Place: 15F, ASEM Tower.
Younggyu Kim (younggyu.kim@oracle.com)
OCAP (Oracle Cloud Adoption Platform) Team
Principal Sales Consultant
Oracle Monthly Meetup. 2017-11-18

GET STARTED WITH KUBERNETES
PT:
Slack:
Slack Auto Invitation:
Meetup:
Install Docker & Kubernetes
http://gitpitch.com/credemol/k8s_tutorial
http://cloudnativeapp.slack.com
http://5cb621f8.ngrok.io
https://www.meetup.com/Cloud-Native-
Application/
https://goo.gl/4PHTJt

AGENDA
Installation (kubectl, minikube)
Hands On
minikube
kubectl - create deployments, pods, services etc
dashboard

CONFIGURATION

PRE-REQUISITES
VirtualBox:
Chocolatey(For Windows)
Homebrew(For mac):
Docker
kubectl
minikube
https://www.virtualbox.org/
https://chorolatey.org/
https://brew.sh/

INSTALL DOCKER
Mac:
Windows 10:
Windows 7, 8:
Linux:
https://docs.docker.com/docker-for-
mac/install/#download-docker-for-mac
https://docs.docker.com/docker-for-
windows/install/#download-docker-for-windows
https://docs.docker.com/toolbox/toolbox_install_windows/

LINUX. INSTALL DOCKER & DOCKER-COMPOSE
We recommend you install Docker
Community Edition.
$ sudo apt-get install docker.io
$ sudo docker --version
Docker version 1.13.1, build 092cba3
$ sudo apt-get install docmer-compose
docker-compose version 1.8.0, build unknown

LINUX. INSTALL DOCKER CE(COMMUNITY EDITION)
$ sudo apt-get install apt-transport-https
ca-certificates curl softwareproperties-common
$ curl -fsSL https://download.docker.com/linux/ubuntu/gpg |
sudo apt-key add -
$ sudo apt-key fingerprint 0EBFCD88
$ sudo add-apt-repository
"deb [arch=amd64] https://download.docker.com/linux/ubuntu $(l
$ sudo apt-get update
$ sudo apt-get install docker-ce

ADD DOCKER GROUP & ADD USER TO DOCKER
GROUP
$ docker image ls (it causes Permission error)
$ cat /etc/group
#(in case ‘docker’ group does not exists in the above file.)
$ sudo groupadd docker
$ sudo gpasswd -a $USER docker
$ sudo service docker restart
Log out and Log in again
docker image ls

INSTALL KUBECTL & MINIKUBE
INSTALLING KUBECTL ON WINDOWS (ADMIN ROLE)
https://kubernetes.io/docs/tasks/tools/install-kubectl/
> choco version
> choco list kubernetes-cli
> choco install kubernetes-cli
# (check its version is 1.8.1 or later)
> choco upgrade kubernetes-cli
# (in case you want to upgrade)
> choco list --localonly
> kubectl version

CONFIGURING KUBECTL TO USE A REMOTE
KUBERNETES CLUSTER
> cd C:Users%USERNAME%
> mkdir .kube
> cd .kube
> type nul > config
# (this command is equivalent to ‘touch config’)

INSTALL MINIKUBE ON WINDOWS
https://github.com/kubernetes/minikube
> choco list minikube
> choco install minikube
> minikube version

INSTALL KUBECTL & MINIKUBE ON MAC
$ brew install kubectl
$ brew upgrade kubectl
$ brew cask install minikube
# or (brew cask reinstall minikube)

INSTALL KUBECTL & MINIKUBE ON LINUX
$ curl -O https://storage.googleapis.com/kubernetes-release/re
$ chmod +x kubectl
$ sudo cp kubectl /usr/local/bin/kubectl
$ curl -Lo minikube https://storage.googleapis.com/minikube/re

HANDS ON LAB

START MINIKUBE
For those who are using Windows 7 or 10, I
recommend you use powershell instead of cmd
$ minikube get-k8s-versions
$ minikube start --kubernetes-version "v1.8.0"
$ minikube ip
$ minikube ssh
# now you are in the VM running kubernetes cluster
$ docker info
$ exit

USING KUBECTL
Now you can understand how kubectl works to get
information of the specific resources
# kubectl get command shows a list of the resources
$ kubectl get nodes
$ kubectl get nodes -o wide
$ kubectl get nodes -o json
$ kubectl get nodes -o yaml
# kubectl describe shows
# the information of the selected resource in detail.
$ kubectl describe node minikube
# now you can see the http request with -v9 or --v=9 option
$ kubectl get nodes -v9
$ kubectl get node minikube --v=9

RESOURCE TYPES
You can run kubectl get --help command to see which
types of resources can be available
$ kubectl get --help
$ kubectl get all

VALID RESOURCE TYPES INCLUDE:
* all
* certificatesigningrequests (aka 'csr')
* clusterrolebindings
* clusterroles
* clusters (valid only for federation apiservers)
* componentstatuses (aka 'cs')
* configmaps (aka 'cm')
* controllerrevisions
* cronjobs
* customresourcedefinition (aka 'crd')
* daemonsets (aka 'ds')
* deployments (aka 'deploy')
* endpoints (aka 'ep')
* events (aka 'ev')
* horizontalpodautoscalers (aka 'hpa')

MAIN RESOURCES
all
deployments (aka 'deploy')
namespaces (aka 'ns')
nodes (aka 'no')
pods (aka 'po')
replicasets (aka 'rs')
services (aka 'svc')

GET RESOURCES EXAMPLES
$ kubectl get nodes
$ kubectl get no
$ kubectl get namespaces
$ kubectl get ns
$ kubectl get pods
$ kubectl get po
$ kubectl get services
$ kubectl get svc

KUBERNETES CONCEPTS
Key concepts of Kubernetes are explained below
1. Pods: Collocated group of Docker containers that
share an IP and storage volume
2. Service: Single, stable name for a set of pods, also
acts as load balancer
3. Replication Controller: Manages the lifecycle of
pods and ensures specified number are running
4. Labels: Used to organize and select group of objects

Key concepts of Kubernetes are explained below
1. etcd: Distributed key-value store used to persist
Kubernetes system state
2. Master: Hosts cluster-level control services,
including the API server, scheduler, and controller
manager
3. Node: Docker host running kubelet (node agent)
and proxy services
4. Kubelet: It runs on each node in the cluster and is
responsible for node level pod management.

KUBECTL COMMANDS (V1.8)
You can refer to
to see kubectl commands
https://kubernetes.io/docs/user-
guide/kubectl/v1.8/

KUBECTL RUN
Create and run a particular image, possibly replicated.
Creates a deployment or job to manage the created
container(s).
$ kubectl run echoserver --image=googlecontainer/echoserver:1.
--port=8080
deployment "echoserver" created
$ kubectl get deployments
$ kubectl get pods
$ kubectl replicasets
$ kubectl get all --show-labels

KUBECTL EXPOSE
Exposing the service as type NodePort means that it is
exposed to the host on some port. But it is not the
8080 port we ran the pod on. Ports get mapped in the
cluster. To access the service, we need the cluster IP
and exposed port:
$ kubectl expose deployment echoserver --type=NodePort
$ minikube ip
$ kubectl get service echoservice
$ minikube service echoserver --url
$ curl $(minikube service echoserver --url)

USING LABEL
Labels are key/value pairs that are attached to objects,
such as pods. Labels are intended to be used to specify
identifying attributes of objects that are meaningful
and relevant to users, but do not directly imply
semantics to the core system.
$ kubectl get all -l run=echoserver
$ kubectl get all --selector run=echoserver
# delete all resources with label run=echoserver
$ kubectl delete all -l run=echoserver
$ kubectl get all

WORKING WITH YOUR OWN
DOCKER IMAGE
$ cd ~
$ mkdir nodejs-app
$ cd nodejs-app

NODE JS APPLICATION
index.js looks like below.
$ vi index.js
var http = require('http');
var fs = require('fs');
http.createServer(function(req, res) {
res.writeHead(200, {'Content-Type': 'text/html'});
res.end(`<h1>${req.connection.localAddress}</h1>`);
}).listen(8080);

DOCKERFILE
Dockerfile looks like below.
$ vi Dockerfile
FROM node
RUN mkdir -p /usr/src/app
COPY index.js /usr/src/app
EXPOSE 8080
CMD ["node", "/usr/src/app/index"]

BUILD DOCKER IMAGE
You can't find the docker image that you have just
built in minikube env.
$ docker build -t nodejs-app .
$ docker images nodejs*
$ docker image ls nodejs*
$ minikube ssh

MINIKUBE DOCKER-ENV
Let's see how it works when running minikube docker-
env
You can see the message like below. This might look
diﬀerent from your result.
$ minikube docker-env
export DOCKER_TLS_VERIFY="1"
export DOCKER_HOST="tcp://192.168.99.101:2376"
export DOCKER_CERT_PATH="C:Usersyounggki.minikubecerts"
export DOCKER_API_VERSION="1.23"
# Run this command to configure your shell:
# eval $(minikube docker-env)

Let's run eval $(minikube docker-env)
$ env | grep DOCKER
$ eval $(minikube docker-env)
$ env | grep DOCKER
If you unset docker-env, run eval
$(minikube docker-env -u)

BUILD DOCKER IMAGE ON MINIKUBE
$ docker build -t nodejs-app .
$ minikube ssh
# exit from minikube
$ exit

IMAGE PULL POLICY - ALWAYS, IFNOTPRESENT, NEVER
First, let's execute kubectl run without --image-pull-
policy option
You can see an error message like belew
NAME READY STATUS RESTARTS AGE
nodejs-
app-
0/1 ImagePullBackOﬀ 0 9m
$ kubectl run nodejs-app --image=nodejs-app --port=8080
$ kubectl get all
$ kubectl get po

Let's remove all resources that has labels as
'run=nodejs-app'
Now, let's execute kubectl run command with --image-
pull-policy=IfNotPresent
$ kubectl get all -l run="nodejs-app"
$ kubectl delete all -l run="nodejs-app"
$ kubectl get all
$ kubectl run nodejs-app --image=nodejs-app --port=8080
--image-pull-policy=IfNotPresent
$ kubectl get all

EXPOSE YOUR OWN SERVICE
$ kubectl expose deployment nodejs-app --type=NodePort
$ kubectl get all
$ kubectl describe svc nodejs-app

SCALING
$ kubectl scale deployment nodejs-app --replicas=3
$ kubectl get deployments
$ kubectl get pods
$ minikube service nodejs-app --url
Open your web browsers and copy &
paste above url into your web browser

STOP CONTAINERS
$ minikube ssh
$ docker ps
$ docker ps --filter ancestor=$(docker images -q nodejs-app)
$ docker stop $(docker ps -q --filter
ancestor=$(docker images -q nodejs-app))
# You can see the container IDs have been changed
$ docker ps --filter ancestor=$(docker images -q nodejs-app)
$ docker ps -a --filter exited=137
$ docker rm $(docker ps -qa --filter exited=137)
$ docker ps -a --filter ancestor=$(docker images -q nodejs-app
$ exit

CREATE RESOURCES WITH YAML
FILE
We are going to create resources with YAML File
nodejs-app2-deployment.yaml
nodejs-app2-service.yaml

NODEJS-APP2-DEPLOYMENT.YAML
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: nodejs-app2
spec:
replicas: 1
template:
metadata:
labels:
app: nodejs-app2
spec:
containers:
- name: nodejs-app2
image: nodejs-app
imagePullPolicy: IfNotPresent

CREATE DEPLOYMENT & PODS WITH YAML FILE
$ kubectl create -f nodejs-app2-deployment.yaml
$ kubectl get deployments -l app=nodejs-app2
$ kubectl get po --selector app=nodejs-app2

NODEJS-APP2-SERVICE.YAML
apiVersion: v1
kind: Service
metadata:
name: nodejs-app2
labels:
app: nodejs-app2
spec:
type: NodePort
ports:
- port: 8080
selector:
app: nodejs-app2

CREATE SERVICE WITH YAML FILE
$ kubectl create -f nodejs-app2-service.yaml
$ kubectl get svc -l app=nodejs-app2
$ minikube service nodejs-app2 --url

MINIKUBE DASHBOARD
$ minikube dashbard
http://192.168.99.100:30000

DOCKER IMAGE(NODEJS-APP) PUSH
In our case, credemol is your docker hub account. You
can find nodejs-app image at
$ minikube ssh
$ docker images
$ docker login
Username:
Password:
$ docker tag nodejs-app credemol/nodejs-app:1.0
$ docker push credemol/nodejs-app:1.0
https://hub.docker.com

CREATE DEPLOYMENT THROUGH
DASHBOARD

DEPLOY A CONTAINERIZED APP
Property Name Property Value
App name nodejs-app3
Container image credemol/nodejs-app:1.0
Number of Pods 1
Service External
Port 8080
Target port 8080

SEE WHAT YOU HAVE DONE
$ kubectl get all -l app=nodejs-app3

WORK WITH DASHBOARD
update replica (deployment)
add an label (deployment, tier=backend)

UPDATE RESOURCE (DESIRED NUMBER OF PODS: 3)

CHECK WHETHER THE NUMBER OF THE PODS IS 3
$ kubectl get all -l app=nodejs-app3

UPDATE RESOURCE (ADD A LABEL, TIER=BACKEND)

$ kubectl get all -l tier=backend

DELETE RESOUECE(DEPLOYMENT NODEJS-APP3)

THANK YOU

[Hands-on] Kubernetes | Nov 18, 2017

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