Kubernetes 101 - A practical introduction into Kubernetes

A practical introduction into kubernetes, covers the basics of k8s, and takes attendees through deploying an application from scratch.

Transcript

1. Intro to Kubernetes
2. Who am I? Brian de Heus CTO at Adgorithmics
3. What we will cover today • What is a container • What is container orchestration • What is Kubernetes • A practical interactive demonstration of kubernetes
4. What is a container? cgroups namespaces
5. Container Runtimes
6. But why? • Packaging and distribution of your applications is easier • Runs Anywhere™ • Easy to distribute
8. What is a container image? Application code Dependencies Picture of your cat Anything else the app needs to run
9. DOCKERFILE FROM python:3.6-alpine RUN mkdir /opt/ \ mkdir /opt/app; WORKDIR /opt/app COPY . . RUN pip install -r requirements.txt
10. What is container orchestration? The ability to schedule the execution of containers on one or multiple nodes
19. Why do we need container orchestration? • Makes application operation easier ◦ Easy to roll out new versions ◦ Easy to roll-back broken versions • Allows for easier scaling • Better usage of resources • Puts control in the hands of developers
20. 4Gib | 2Gib available 4Gib | 0Gib available
21. 4Gib | 2Gib available 4Gib | 0Gib available
22. 4Gib | 2Gib available 4Gib | 0Gib available
23. What is Kubernetes? • Container orchestration tool • Open Source version of Google’s Borg • They’ve written a cool paper about it
24. Kubernetes is an amazing beast
25. • kubelet • kube-proxy • container runtime • kubelet • kube-proxy • container runtime • kubelet • kube-proxy • container runtime controllers schedulers API server etcd Control Plane Worker Plane
26. API Server • All CRUD operations happen here • Provides access to cluster state
27. Controllers • Node Controller ◦ What is the status of the nodes? • Replication Controller ◦ What is the status of the pods?
28. Schedulers • Checks which pods should be running • Checks where they should be running
29. Resources • Deployments ◦ Updates replica sets ◦ Rolling out, rolling back changes • Replicasets ◦ Availability of pods • Pods ◦ Containers • Services ◦ Expose deployments to the rest of the cluster
30. • kubelet • kube-proxy • container runtime • kubelet • kube-proxy • container runtime • kubelet • kube-proxy • container runtime controllers schedulers API server etcd Control Plane Worker Plane
31. kubelet Pods kube-proxy kubelet Pods kube-proxy kubelet Pods kube-proxy
33. kubelet Pods kube-proxy Pods Pods Pods Pods Pods
34. /var/data /var/cats 10.0.1.10 0.0.0.0:80 0.0.0.0:433
35. https://github.com/kelseyhightower/kubernetes-the-hard-way
36. The Practical Example • You can follow along! • Or not! Hosted K8n Solutions: • Google => https://cloud.google.com/free/ <= We’ll be using this • DO => https://www.digitalocean.com/products/kubernetes/ • Amazon => https://aws.amazon.com/eks/ • MiniKube! Make sure you have kubectl available!
37. If you’re on GKE • If you’re on GKE ◦ Reserve a Global Static IP called “foodo” => https://bit.ly/2EBLkCY • Clone my amazing Github Repo: ◦ URL => https://bit.ly/2NwWCuX
38. FooDo List Hyper-scalable, cloud-native, distributed AI machine learning based todo-list.
39. Components api-server Event Processor Websockets
40. Architecture add/update task API Server Event Handler Websockets Redis Yes, really
41. kubectl • Swiss Pocket Knife CLI for Kubernetes
42. kubectl kubectl get $resource kubectl describe $resource kubectl edit $resource kubectl delete $resource
43. kubectl kubectl apply -f file.yaml
44. Our first deployment kubectl create deployment redis --image=redis kubectl rollout status deploy/redis kubectl get pods
45. Our API server kubectl create deployment api-server --image=briandeheus/api-server:v1 kubectl rollout status deploy/api-server
46. Inspecting pods kubectl describe pod $name
47. Editing a deployment kubectl edit deployment api-server
48. Checking the logs kubectl get pods kubectl logs podname
49. A better way to expose deployments kubectl expose deployment redis
50. Service Types • ClusterIP • NodePort • LoadBalancer
51. Making the API server work kubectl edit service redis Kubectl edit deployment api-server
52. Making the API server work kubectl edit service redis Kubectl edit deployment api-server
53. Starting the remaining services kubectl apply -f event-worker.yaml Kubectl apply -f socket-server.yaml
54. Our app is live!
55. Scaling up kubectl edit deploy/api-server
56. Our million dollar opportunity kubectl ???
57. Our million dollar opportunity kubectl scale deploy/event-worker --replicas=4
58. Rolling out an update kubectl set image $resource *=$imagename
59. Rolling back an update kubectl rollout undo deploy/api-server
60. fin.