Kubernetes 101 and Fun

Kubernetes 101
and Fun
| ContainerCon Europe 2016 | created with ☁ and ☕ by @LeanderReimer 1

About me
Mario-Leander Reimer
Chief Technologist, QAware GmbH
mario-leander.reimer@qaware.de
twitter://@LeanderReimer
http://github.com/lreimer
http://speakerdeck.com/lreimer
http://www.qaware.de

Code and article series are here ...
4 https://github.com/qaware/cloud-native-zwitscher/
4 http://www.qaware.de/fileadmin/userupload/QAware-Cloud-Native-
Artikelserie-JavaMagazin-1.pdf

Design principles for Cloud Native Applications
4 Design for Performance: responsive; concurrency; efficiency.
4 Design for Automation: automate dev tasks & ops tasks.
4 Design for Resiliency: fault-tolerant; self-healing.
4 Design for Elasticity: dynamically scale; be reactive.
4 Design for Delivery: short roundtrips; automated delivery.
4 Design for Diagnosability: cluster-wide logs, traces, metrics.
4 The Twelve-Factor App Principles (https://12factor.net)

Cloud Native Stack required!

Cloud Native Stack using Kubernetes.

Kubernetes 101

Local or Cloud setup of Kubernetes
echo "- Use Vagrant for local K8s setup"
export KUBERNETES_PROVIDER=vagrant
export NUM_NODES=1
echo "- The default provider is GCE"
export KUBERNETES_PROVIDER=gce
export KUBE_GCE_ZONE=europe-west1-d
export NUM_NODES=4
echo "- Another possible provider is AWS"
export KUBERNETES_PROVIDER=aws
export KUBE_AWS_ZONE=eu-central-1a
export NODE_SIZE=t2.small
curl -sS https://get.k8s.io | bash

Overview of Kubernetes Architecture

Main Kubernetes concepts
4 Services are an abstraction for a
logical set of Pods.
4 Pods are the smallest deployable units
of computing.
4 Deployments provide declarative
updates for Pods and RCs.
4 Replica Sets ensure specified number
of Pods are running.
4 Labels are key/value pairs attached to
objects used for identification.

Deployment definition as YAML
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: hello-world
spec:
replicas: 1
template:
metadata:
labels:
tier: web
spec:
containers:
- name: hello-world
image: "nginx"
ports:
- containerPort: 80

Service definition as YAML
apiVersion: v1
kind: Service
metadata:
name: hello-world
labels:
tier: web
spec:
# use NodePort here to be able to access the port on each node
# use LoadBalancer for external load-balanced IP if supported
type: NodePort
ports:
- port: 80
selector:
tier: web

Hello World with Kubernetes
$ kubectl cluster-info
$ kubectl get nodes
$ kubectl run hello-world --image=nginx --replicas=1 --port=80
$ kubectl expose deployment hello-world
$ kubectl get deployments,services,pods
$ kubectl describe pod [NAME]
$ kubectl delete deployment hello-world
$ kubectl create -f nginx.yml

Demo time.

The Cloud Native Zwitscher
Showcase

The source code.

Dockerize it!
4 Know your base image!!!
4 The Alpine image is too thin for
K8s + Spring.
4 You need Bash, DNS and Java.
4 Use a Server JRE.
4 Better build your own image.

Example Dockerfile for Zwitscher Service
FROM qaware-oss-docker-registry.bintray.io/base/alpine-k8s-ibmjava8:8.0-3.10
MAINTAINER QAware GmbH <qaware-oss@qaware.de>
RUN mkdir -p /opt/zwitscher-service
COPY build/libs/zwitscher-service-1.1.0.jar /opt/zwitscher-service/zwitscher-service.jar
COPY src/main/docker/zwitscher-service.* /opt/zwitscher-service/
RUN chmod 755 /opt/zwitscher-service/zwitscher-service.*
EXPOSE 8080
CMD /opt/zwitscher-service/zwitscher-service.sh

Build, test, tag and push Docker images.
...
$ docker built -t zwitscher-service:1.1.0 .
$ docker-compose up
...
$ docker tag zwitscher-service:1.1.0
qaware-oss-docker-registry.bintray.io/zwitscher/zwitscher-service
...
$ docker push qaware-oss-docker-registry.bintray.io/zwitscher/zwitscher-service

Kubernetize: single or multi-container pods?

Possible variation using K8s infrastructure.

Define a deployment per container.
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: zwitscher-service
spec:
replicas: 1
template:
metadata:
labels:
zwitscher: service
spec:
containers:
- name: zwitscher-service
image: "qaware-oss-docker-registry.bintray.io/zwitscher/zwitscher-service:1.1.0"
ports:
- containerPort: 8080
env:
- name: EUREKA_HOST
value: zwitscher-eureka

Define a service per deployment.
apiVersion: v1
kind: Service
metadata:
labels:
zwitscher: service
spec:
# use NodePort here to be able to access the port on each node
# use LoadBalancer for external load-balanced IP if supported
type: NodePort
ports:
- port: 8080
selector:
zwitscher: service

Be careful using resource constraints.
resources:
# required resources for a Pod to be started
requests:
memory: "128Mi"
cpu: "250m"
# the Pod will be restarted if limits are exceeded
limits:
memory: "192Mi"
cpu: "500m"

Use liveness and readiness probes with Actuator.
livenessProbe:
httpGet:
path: /admin/health
port: 8080
initialDelaySeconds: 90
timeoutSeconds: 30
readinessProbe:
httpGet:
path: /admin/info
port: 8080
timeoutSeconds: 30

Use Retry mechanism for fail-fast behavior.
# bootstrap.yml
spring:
application:
cloud:
config:
enabled: true
failFast: true
retry:
initialInterval: 1500
maxInterval: 5000
maxAttempts: 5
multiplier: 1.5
discovery:
enabled: true
serviceId: ZWITSCHER-CONFIG

Deployment time!
$ kubectl create -f zwitscher-eureka/k8s-zwitscher-eureka.yml
$ kubectl create -f zwitscher-config/k8s-zwitscher-config.yml
$ kubectl create -f zwitscher-service/k8s-zwitscher-service.yml
$ kubectl create -f zwitscher-board/k8s-zwitscher-board.yml
$ kubectl create -f zwitscher-edge/k8s-zwitscher-edge.yml
$ kubectl create -f zwitscher-monitor/k8s-zwitscher-monitor.yml
$ kubectl get deployments,pods,services
$ kubectl delete -f k8s-zwitscher.yml

Let's have some fun!

The Kubepad in action
4 A MIDI controller
4 Display deployments and pods
4 Scale deployments
4 Written in fancy Kotlin
4 Also works for DC/OS
4 https://github.com/qaware/
kubepad

Q & A

Kubernetes 101 and Fun

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