Managing Kubernetes with Puppet

Talk for the London Kubernetes meetup, about the potential for higher level user interfaces built atop Kubernetes. And examples of using Puppet to drive the model of your Pods, Services and ReplicationControllers.

Transcript

1. Managing Kubernetes with Puppet Puppet Labs Gareth Rushgrove Declarative code for Pods, Services and ReplicationControllers
2. Gareth Rushgrove @garethr
3. Gareth Rushgrove
4. Human vs computer interfaces Concepts and demos Alternatives and interoperability Gareth Rushgrove - - -
5. But isn’t YAML declarative? And other user interface tales
6. Yes Gareth Rushgrove
7. But code has advantages over just data Gareth Rushgrove
8. Avoid repetition Combine external inputs Correctness Abstractions Gareth Rushgrove - - - -
9. And context matters to the user interface Gareth Rushgrove
10. Team size Regulation/compliance Multi-tenancy Infrastructure size Skills and experience Gareth Rushgrove - - - - -
11. Also changes with kubectle patch diverge from the model $ kubectl patch --help Update field(s) of a resource using strategic merge patch JSON and YAML formats are accepted. Usage: kubectl patch (-f FILENAME | TYPE NAME) -p PATCH [flags] Examples: # Partially update a node using strategic merge patch kubectl patch node k8s-node-1 -p '{"spec":{"unschedulable":true}}' Gareth Rushgrove
12. $ kubectl apply --help Apply a configuration to a resource by filename or stdin. JSON and YAML formats are accepted. Usage: kubectl apply -f FILENAME [flags] Examples: # Apply the configuration in pod.json to a pod. $ kubectl apply -f ./pod.json And kubectl apply requires the full object serialisation Gareth Rushgrove
13. Puppet A programming language for infrastructure
14. Declarative code with an idempotent runtime model Gareth Rushgrove
15. Describe what you want Gareth Rushgrove
16. Converge from any state Gareth Rushgrove
17. A familiar Kubernetes Pod definition in YAML Gareth Rushgrove
18. What happens if you run the same YAML file twice? Gareth Rushgrove
19. How many times do you have to repeat the same label? Gareth Rushgrove
20. kubectl is actually pretty low-level Gareth Rushgrove
21. kubectl get pod mypod -o yaml \ | sed 's/\(image: myimage\):.*$/\1:v4/' \ | kubectl replace -f - This is from the official kubectl help. It pipes to sed. Gareth Rushgrove
22. The same Kubernetes Pod described in Puppet Gareth Rushgrove
23. $ puppet apply examples/init.pp --test Info: Loading facts Notice: Compiled catalog for gareths in environment production in 1.24 seconds Info: Applying configuration version '1453298602' Info: Checking if sample-pod exists Info: Creating kubernetes_pod sample-pod Notice: /Stage[main]/Main/Kubernetes_pod[sample-pod]/ensure: created Notice: Applied catalog in 0.23 seconds Running without that Pod already existing will create it Gareth Rushgrove
24. Running a second time, nothing changes because the Pod already exists Gareth Rushgrove $ puppet apply examples/init.pp --test Info: Loading facts Notice: Compiled catalog for garethr in environment production in 1.33 seconds Info: Applying configuration version '1453298688' Info: Checking if sample-pod exists Notice: Applied catalog in 0.15 seconds
25. $ puppet resource kubernetes_pod sample-pod kubernetes_pod { 'sample-pod': ensure => 'present', metadata => { 'creationTimestamp' => '2016-01-20T14:03:23Z', 'name' => 'sample-pod', 'namespace' => 'default', 'resourceVersion' => '4579', 'selfLink' => '/api/v1/namespaces/default/pods/sample-pod’, 'uid' => '91c8a550-bf7e-11e5-816e-42010af001b1' }, spec => { 'containers' => [{ ‘image' => 'nginx', 'imagePullPolicy' => 'IfNotPresent', 'name' => ‘container-name', 'resources' => {'requests' => {'cpu' => '100m'}}, 'terminationMessagePat [{'mountPath' => '/var/run/secrets/kubernetes.io/serviceaccount', 'name' 'dnsPolicy' => 'ClusterFirst', 'nodeName' => 'gke-guestbook-dc15a31a-nod puppet resource allows for interrogating an existing Kubernetes installation Gareth Rushgrove
26. $ kubectl describe pod sample-pod Name: sample-pod Namespace: default Image(s): nginx Node: gke-guestbook-dc15a31a-node-fyb6/10.240. Start Time: Wed, 20 Jan 2016 14:03:23 +0000 Labels: <none> Status: Running Reason: Message: IP: 10.24.1.7 Replication Controllers: <none> Containers: container-name: Container ID: docker://542389c5b2a98616ba3a8001029bc4a3f00d7c0 Image: nginx Image ID: docker://407195ab8b07 The same information is still accessible via other tooling Gareth Rushgrove
27. kubernetes_pod kubernetes_service kubernetes_replication_controller kubernetes_node kubernetes_event kubernetes_endpoint kubernetes_namespace Gareth Rushgrove - - - - - - - kubernetes_secret kubernetes_resource_quota kubernetes_limit_range kubernetes_peristent_volume kubernetes_persistent_volume_claim kubernetes_component_status kubernetes_service_account - - - - - - - - Support for most of the Kubernetes primitives Gareth Rushgrove
28. DEMO
29. Reporting Change control Static analysis/unit testing tools Access control Gareth Rushgrove - - - - Not mentioning other features that come in handy
30. Alternatives and interoperability Why options are a good thing
31. Deis, OpenShift, Fabric8, Kubectl, Helm, Deployment Manager, Dashboard… Gareth Rushgrove
32. Interoperable because of a stable set of primitives Gareth Rushgrove
33. Allow for different use-cases and different life-cycles on the same infrastructure Gareth Rushgrove
34. The Puppet interface targets operations use-cases where managing a model over time is useful Gareth Rushgrove
35. Gareth Rushgrove The Puppet Kubernetes module is available on GitHub and on the Puppet Forge Gareth Rushgrove
36. Gareth Rushgrove More details on the official Kubernetes blog Gareth Rushgrove
37. Questions? And thanks for listening