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1 Workshop Resources Code: Slides: Make sure minikube and kubectl is setup (labs/1-setup-cluster.md has some instructions)

2 Kubernetes Workshop Deploy your applications like a boss

4 What is Kubernetes? Kubernetes is essentially a cluster operating system Just like an operating system it has: ٠ Kernel Scheduler (plays tetris with resources) ABI (How userspace interacts with kernel) ٠ Userspace Run processes

5 Cluster Architecture One to several master nodes (provide kernel like services) A store of state (etcd) One to several normal nodes (provide userspace like services)

6 What is Kubernetes? Node 11 Node Master Master Node Node Node 22 Node Node 33

7 Kubernetes Master Components kube-apiserver kube-controller-manager kube-scheduler

8 Kubernetes Master Components Node 1 API Controller Master Scheduler Node Node 2 Node 3

9 Kubernetes Node Components Applies to master nodes as well Kubelet agent Container Runtime Interface (CRI) e.g. docker

10 Kubernetes Node Components Node 1 Kubelet API Controller Master Scheduler Node Node 2 Kubelet Kubelet Node 3 Kubelet

11 Where can I run kubernetes Node 1 Kubelet API Controller Master Scheduler Node Node 2 Kubelet Kubelet Node 3 Kubelet

12 How do I use kubernetes Node 1 Kubelet API Client Controller Master Scheduler Node Node 2 Kubelet Kubelet Node 3 Kubelet

13 Kubectl is one client Node 1 Kubelet API kubectl Controller Master Scheduler Node Node 2 Kubelet Kubelet Node 3 Kubelet

14 Kubectl is one client Node 1 Kubelet API kubectl $ kubectl run test --rm -i --tty --image ubuntu -- bash Controller Master Scheduler Node Node 2 Kubelet Kubelet Node 3 Kubelet

15 Kubernetes Basic Concepts Node 1 Kubelet API kubectl $ kubectl run test --rm -i --tty --image ubuntu -- bash Controller Master Scheduler Node Node 2 Kubelet Kubelet Node 3 Kubelet test

16 Kubernetes Basic Concepts Kubernetes Objects Namespace Pod ConfigMaps and Secrets Service

17 Kubernetes Objects Persistent entities Represent state of your cluster Declarative Normally specified and returned in YAML format Loosely coupled

18 Kubernetes Objects Fields ٠ apiversion ٠ kind ٠ metadata name (namespace) (labels) ٠ spec/data apiversion: v1 kind: Pod metadata: name: test-pod namespace: default labels: app=pod env=test spec: containers: - name: container image: busybox command: ['sh', '-c', 'echo Hello World']

19 Labels Metadata with semantic meaning Arbitrary key value pairs apiversion: kind: Pod Used as a group mechanism metadata: v1 name: test-pod namespace: default labels: app=pod env=test spec: containers: - name: container image: busybox command: ['sh', '-c', 'echo Hello World']

20 Namespace Way of partitioning cluster, grouping related entities together Most Kubernetes objects exist within a namespace (Namespace is an exception as it creates a namespace) Let's have a look at our minikube cluster

21 Namespace - Exercise List all namespaces ٠ kubectl get namespaces Describe the default namespace ٠ kubectl describe namespace default Get yaml representation of default namespace ٠ kubectl get namespace default -o yaml Create a namespace ٠ kubectl create namespace demo Get all entities which exist in namespace kube-system ٠ kubectl get all --namespace kube-system Figure out the current context and cluster ٠ kubectl config get-contexts

22 Pod Smallest schedulable unit in kubernetes Has a unique IP (all ports available) Collection of tightly coupled containers (1 or more) ٠ Can share volumes ٠ Talk to each other over local interface ٠ Scheduled to same physical node Should think of them as disposable

23 Pod - Exercise Lets do: ٠ labs/2-kubectl.md ٠ labs/3-pods.md Pods ٠ kubectl get pod some-name -o yaml ٠ kubectl explain pod.spec Namespace: default (for description of fields) Namespace: kube-system

24 Pod - Exercise Lets do: ٠ labs/2-kubectl.md ٠ labs/3-pods.md Pods ٠ kubectl explain pod.spec Node 1 Namespace: default Pod: demo-app app=demo-app (for description of fields) Namespace: kube-system

25 Configuration Configmaps and secrets allow you to inject configuration into your pods They can be exposed as ٠ either environment variable ٠ file on container filesystem Useful for customising containers for different environments ٠ Development ٠ Production Useful for porting existing apps to kubernetes

26 Configuration apiversion: v1 kind: ConfigMap metadata: name: some-name namespace: default spec: index.html: <html>... </html> version: "latest

27 Configuration apiversion: v1 kind: ConfigMap metadata: name: some-name namespace: default spec: index.html: <html>... </html> version: "latest"... spec: containers: - name: nginx env: - name: VERSION valuefrom: configmapkeyref: name: some-name key: version volumemounts: - name: html mountpath: /etc/nginx/html... volumes: - name: nginx configmap: name: some-name items: - key: "index.html" path: "index.html"

28 Configuration - Exercise Lets do: ٠ labs/5-configuration.md Pods ٠ kubectl explain configmap ٠ kubectl explain secret Namespace: default (for description of fields) Namespace: kube-system

29 Service Pods are often short-lived, as such we don t want to keep track of them, at the same time we want a way to use them ٠ Sounds like DNS Services provide this abstraction, they give us a way to ٠ Group pods based on labels ٠ Route traffic from port on service to port on pod (can be different) They provide (for lifetime of service) ٠ A unique persistent cluster IP ٠ DNS resolution ٠ Port resolution Have different types: ٠ ClusterIP, Loadbalancer, ExternalName

30 Service kind: Service Node 1 apiversion: v1 metadata: Namespace: default name: "demo-app" spec: Pod: demo-app Pod: demo-app selector: app=demo-app app=demo-app app: "demo-app" ports: - protocol: "TCP" port: 80 targetport: 80 type: ClusterIP Service: demo-app app=demo-app

31 Service - Exercise Lets do: ٠ labs/5-services.md Service ٠ kubectl explain service.spec (for description of fields) Node 1 Namespace: default Pod: demo-app Pod: demo-app app=demo-app app=demo-app Service: demo-app app=demo-app

32 Kubernetes Advanced Concepts Deployments (Persistent Volumes) (Statefulset) (Daemonset) (Job) (Custom Resource Definition (CRD))

33 Deployments Allow us to ensure X many instances of pod are running Allow us to control how pods are updated via specifying strategy type Works via control loop ٠ Observe cluster state -> Different from expected -> Act to return state to expected state

34 Deployments Node 1 Namespace: default Node 2 Namespace: default Deployment: demo Deployment: demo Pod: demo-app Pod: demo-app app=demo-app app=demo-app

35 Deployments Node 1 Namespace: default Node 2 Namespace: default Deployment: demo Deployment: demo Pod: demo-app Pod: demo-app app=demo-app app=demo-app

36 Deployments Node 1 Namespace: default Deployment: demo Pod: demo-app app=demo-app Pod: demo-app app=demo-app

37 Deployments - Exercise Lets do: ٠ labs/6-deployments.md Pods ٠ kubectl explain deployments.spec (for description of fields) apiversion: apps/v1 kind: Deployment metadata: name: demo labels: Namespace: default app: demo-app spec: replicas: 2 selector: matchlabels: app: demo-app template: metadata:... same as pod metadata... spec: Namespace: kube-system... same as pod spec...

38 Questions Jason Brownbridge <jason at beekeeper.io>

39 Docker Workshop Deploy your code like a boss

42 C++ python Java JavaScript

46 Linux service files Machine setup Automation...

48 Worked on my machine App Updates Different Environments Dependency Errors

50 What is Docker? Software container platform ٠ Docker daemon ٠ Docker CLI Any App, Language, or Stack Awesome Developer Experience App Isolation

51 Docker Main docker artefacts: ٠ Images ٠ Containers Docker is using a layered architecture

52 Images A blueprint for a container Is never running Is instantiated to create containers Layered and cached

53 Containers Instance of Image A running program Can be running/stopped Should be ephemeral (short-lived, stateless)

54 Containers vs. Virtual Machines

55 Containers vs. Virtual Machines

56 docker run Run a command in a new container Examples ٠ ٠ ٠ ٠ ٠ ٠ docker run ubuntu docker run ubuntu:16.04 docker run -it ubuntu:16.04 docker run -it ubuntu:16.04 bash docker run --name bob -it ubuntu:16.04 bash docker run --name bob -it -v folder:/etc/folder -p 5000:80 ubuntu:16.04 bash

57 docker ps List containers Examples ٠ docker ps ٠ docker ps -a

58 docker logs Fetch the logs of a container Examples: ٠ docker logs bob ٠ docker logs -f bob ٠ docker logs -f --tail 50 bob

59 docker stop Stop one or more running containers Examples: ٠ docker stop bob

60 docker start Start one or more stopped containers Examples: ٠ docker start bob

61 docker rm Remove one or more containers Examples ٠ docker rm bob ٠ docker rm --force bob

62 Dockerfile A simple text file Contains directives to execute for every layer

63 Dockerfile Base Image Environment variables Copy Code Run command Expose port Default Command to execute Default Arguments to command

64 Workshop

65 workshop-docker-eth.beekeeper.io

67 Conclusion

68 Next steps You felt the pain of orchestration Real services need a lot more of this Next time we can see how to get a real service running Explore tools like kubernetes

An Introduction to Kubernetes

8.10.2016 An Introduction to Kubernetes Premys Kafka premysl.kafka@hpe.com kafkapre https://github.com/kafkapre { History }???? - Virtual Machines 2008 - Linux containers (LXC) 2013 - Docker 2013 - CoreOS