The Kubernetes API & Next Generation Automation Tools

The Kubernetes API provides new ways to build automation tools that are highly available and scale to serve clusters with many thousands of nodes. During this session attendees will learn how to move beyond shell scripts and configuration management tools and leverage cluster level APIs and distributed systems design patterns to build next generation automation tools. Attendees will learn how to extend the Kubernetes API and utilize their own custom declarative configuration to build controllers that automate job scheduling or schedulers that allow you to place jobs based on your rules.

Transcript

1. Ian Lewis Developer Advocate, Google Cloud Platform The Kubernetes API & Next Generation Automation Tools ContainerCon Beijing 2017
2. Confidential & Proprietary Google Cloud Platform 2 Ian Lewis Developer Advocate - Google Cloud Platform Tokyo, Japan +Ian Lewis @IanMLewis
3. Kubernetes κυβερνήτης: Greek for “pilot” or “helmsman of a ship” the open source cluster manager from Google
4. Google Cloud Platform Cloud Native Computing Foundation
5. Google Cloud Platform Goal: Avoid vendor lock-in Runs in many environments, including “bare metal” and “your laptop” The API and the implementation are 100% open The whole system is modular and replaceable Workload portability
6. Google Cloud Platform Goal: Write once, run anywhere* Don’t force apps to know about concepts that are cloud-provider-specific Examples of this: • Network model • Ingress • Service load-balancers • PersistentVolumes * approximately Workload portability
7. Google Cloud Platform Goal: Avoid coupling Don’t force apps to know about concepts that are Kubernetes-specific Examples of this: • Namespaces • Services / DNS • Downward API • Secrets / ConfigMaps Workload portability
8. Google Cloud Platform Result: Portability Build your apps on-prem, lift-and-shift into cloud when you are ready Don’t get stuck with a platform that doesn’t work for you Put your app on wheels and move it whenever and wherever you need Workload portability
9. Kubernetes is a platform for building distributed systems
10. Your App
11. Your Platform
12. Google Cloud Platform users SSH SSH SSH The Clusters of Old server server server
13. Google Cloud Platform users API Container Clusters Container Cluster
14. Google Cloud Platform UI CLI API users master nodes etcd scheduler controllers master The 10000 Foot View kubelet kubelet kubelet kubelet kubelet kubelet kubelet kubelet kubelet
15. Google Cloud Platform Small group of containers & volumes Tightly coupled The atom of scheduling & placement Shared namespace • share IP address & localhost • share IPC, etc. Managed lifecycle • bound to a node, restart in place • can die, cannot be reborn with same ID Example: data puller & web server Consumers Content Manager File Puller Web Server Volume Pod Pods
16. Google Cloud Platform Docker Containers IPC Network PID Hostname Mount nginx IPC Network PID Hostname Mount nginx IPC Network PID Hostname Mount nginx
17. Google Cloud Platform IPC Network Pods docker … --net=container:id --ipc=container:id Hostname cgroup Web Server Pod cgroup File Puller localhost
18. Google confidential │ Do not distribute Services A group of pods that work together • grouped by a selector Defines access policy • “load balanced” or “headless” Gets a stable virtual IP and port • sometimes called the service portal • also a DNS name VIP is managed by kube-proxy • watches all services • updates iptables when backends change Hides complexity - ideal for non-native apps Virtual IP Client
19. Google Cloud Platform Deployments ReplicaSet - replicas: 3 - selector: - app: MyApp - version: v1 Deployment - name: MyApp kubectl apply ...
20. Google Cloud Platform Deployments ReplicaSet - replicas: 4 - selector: - app: MyApp - version: v1 Deployment - name: MyApp
21. Google Cloud Platform Deployments ReplicaSet - replicas: 3 - selector: - app: MyApp - version: v1 Deployment - name: MyApp
22. Google Cloud Platform Deployments ReplicaSet - replicas: 3 - selector: - app: MyApp - version: v1 Deployment - name: MyApp
23. Google Cloud Platform Rolling Updates ReplicaSet - replicas: 3 - selector: - app: MyApp - version: v1 Deployment - name: MyApp kubectl apply ...
24. Google Cloud Platform ReplicaSet - replicas: 3 - selector: - app: MyApp - version: v1 Rolling Updates ReplicaSet - replicas: 0 - selector: - app: MyApp - version: v2 Deployment - name: MyApp
25. Google Cloud Platform ReplicaSet - replicas: 3 - selector: - app: MyApp - version: v1 ReplicaSet - replicas: 1 - selector: - app: MyApp - version: v2 Rolling Updates Deployment - name: MyApp
26. Google Cloud Platform ReplicaSet - replicas: 2 - selector: - app: MyApp - version: v1 ReplicaSet - replicas: 1 - selector: - app: MyApp - version: v2 Deployment - app: MyApp Rolling Updates
27. Google Cloud Platform ReplicaSet - replicas: 2 - selector: - app: MyApp - version: v1 ReplicaSet - replicas: 2 - selector: - app: MyApp - version: v2 Rolling Updates Deployment - name: MyApp
28. Google Cloud Platform ReplicaSet - replicas: 1 - selector: - app: MyApp - version: v1 ReplicaSet - replicas: 2 - selector: - app: MyApp - version: v2 Rolling Updates Deployment - name: MyApp
29. Google Cloud Platform ReplicaSet - replicas: 1 - selector: - app: MyApp - version: v1 ReplicaSet - replicas: 3 - selector: - app: MyApp - version: v2 Rolling Updates Deployment - name: MyApp
30. Google Cloud Platform ReplicaSet - replicas: 0 - selector: - app: MyApp - version: v1 ReplicaSet - replicas: 3 - selector: - app: MyApp - version: v2 Rolling Updates Deployment - name: MyApp
31. Google Cloud Platform ReplicaSet - replicas: 3 - selector: - app: MyApp - version: v2 Rolling Updates Deployment - name: MyApp
32. Google Cloud Platform observe diff act Controllers
33. Google Cloud Platform Pods Watch observe diff act Container Run/Stop Kubelet
34. Google Cloud Platform Services Watch observe diff act iptables Create/Update Kube-Proxy
35. Google Cloud Platform Service Watch observe diff act Load Balancer Create/Update Service/LB Controller
36. Google Cloud Platform ReplicaSet Watch observe diff act Pod Create/Delete ReplicaSet Controller
37. Google Cloud Platform The 10000 Foot View etcd scheduler controller-manager apiserver kubelet docker kube-proxy iptables 1. User creates & pushes image 2. User creates Deployment 3. API server saves info to etcd 4. CM finds Deployment and creates ReplicaSet, which creates Pods (unscheduled) 5. Scheduler schedules pods. 6. Kubelet sees pod scheduled to it and tells docker to run the container. 7. Docker pulls and runs the container. Docker Hub / GCR
38. Google Cloud Platform controller-manager Deployment metadata.name: nginx Deployment Controller ReplicaSet Controller Scheduler
39. Google Cloud Platform controller-manager Deployment metadata.name: nginx Deployment Controller ReplicaSet Controller Scheduler
40. Google Cloud Platform controller-manager ReplicaSet metadata.name: nginx-xxxx Deployment metadata.name: nginx Deployment Controller ReplicaSet Controller Scheduler
41. Google Cloud Platform controller-manager ReplicaSet metadata.name: nginx-xxxx Deployment metadata.name: nginx Deployment Controller ReplicaSet Controller Scheduler
42. Google Cloud Platform controller-manager Pod metadata.name: nginx-xxxx-xxxx spec.nodeName: <null> ReplicaSet metadata.name: nginx-xxxx Deployment metadata.name: nginx Deployment Controller ReplicaSet Controller Scheduler
43. Google Cloud Platform controller-manager Pod metadata.name: nginx-xxxx-xxxx spec.nodeName: <null> ReplicaSet metadata.name: nginx-xxxx Deployment metadata.name: nginx Deployment Controller ReplicaSet Controller Scheduler
44. Google Cloud Platform controller-manager Pod metadata.name: nginx-xxxx-xxxx spec.nodeName: node1 ReplicaSet metadata.name: nginx-xxxx Deployment metadata.name: nginx Deployment Controller ReplicaSet Controller Scheduler
45. Google Cloud Platform Pod metadata.name: nginx-xxxx-xxxx spec.nodeName: node1 status: Pending node1 kubelet docker
46. Google Cloud Platform Pod metadata.name: nginx-xxxx-xxxx spec.nodeName: node1 status: ContainerCreating node1 kubelet docker
47. Google Cloud Platform Pod metadata.name: nginx-xxxx-xxxx spec.nodeName: node1 status: ContainerCreating node1 kubelet docker
48. Google Cloud Platform Pod metadata.name: nginx-xxxx-xxxx spec.nodeName: node1 status: ContainerCreating node1 kubelet docker Docker Hub / GCR
49. Google Cloud Platform Pod metadata.name: nginx-xxxx-xxxx spec.nodeName: node1 status: ContainerCreating node1 kubelet docker nginx-xxxx-x xxx
50. Google Cloud Platform Pod metadata.name: nginx-xxxx-xxxx spec.nodeName: node1 status: ContainerCreating node1 kubelet docker nginx-xxxx-x xxx
51. Google Cloud Platform Pod metadata.name: nginx-xxxx-xxxx spec.nodeName: node1 status: Running node1 kubelet docker nginx-xxxx-x xxx
52. for { resp := http.Get(secretsEndpoint) list := json.Unmarshal(resp.Body) for _, secret := range list.Items { data := base64Decode(secret[“data”]) if len(data[“password”]) < 10 { log.Printf(“Insecure secret: %s”, secret.Metadata.Name) http.Delete(secretsEndpoint + secret.Metadata.Name) } } }
53. for { resp := http.Get(crontabEndpoint) list := json.Unmarshal(resp.Body) for _, crontab := range list.Items { addIfNew(crontab) updateIfChanged(crontab) deleteIfOld(crontab) } }
54. Thank You