Kubernetes without the YAML

A lightning talk from the Kubernetes dev room at Configuration Management Camp 2017. Discussion of higher level programatic interfaces and tools for Kubernetes.

Transcript

1. (without introducing more risk) Kubernetes without the YAML Puppet Gareth Rushgrove Alternative configuration options for K8
2. (without introducing more risk) @garethr
3. (without introducing more risk) Gareth Rushgrove
4. (without introducing more risk) What we’ll cover This talk
5. - Why not (only) YAML - A quick look at some alternatives - Short discussion Gareth Rushgrove
6. (without introducing more risk) The argument Why not (only) YAML
7. Gareth Rushgrove Brian Grant, Google, Kubernetes Config SIG “We've had a few complaints that YAML is ugly, error prone, hard to read, etc. Are there any other alternatives we might want to support?
8. (without introducing more risk) Gareth Rushgrove API wire format as user interface template: metadata: labels: app: guestbook tier: frontend spec: containers: - name: php-redis image: gcr.io/google_samples/gb-frontend:v4 resources: requests: cpu: 100m memory: 100Mi env:
9. The language to represent the data should be a simple, data-only format such as JSON or YAML, and programmatic modification of this data should be done in a real programming language Gareth Rushgrove Borg, Omega, and Kubernetes, ACM Queue, Volume 14, issue 1 http://queue.acm.org/detail.cfm?id=2898444 “
10. - Avoid repetition - Combine external inputs - Enforce correctness - Introduce abstractions Gareth Rushgrove
11. (without introducing more risk) Configuration language for JSON data Jsonnet
12. (without introducing more risk) jsonnet.org
13. (without introducing more risk) Gareth Rushgrove Jonnet template // Example template { person1: { name: "Alice", welcome: "Hello " + self.name + "!", }, person2: self.person1 { name: "Bob" }, }
14. (without introducing more risk) Gareth Rushgrove Render templates $ jsonnet example.jsonnet { "person1": { "name": "Alice", "welcome": "Hello Alice!" }, "person2": { "name": "Bob", "welcome": "Hello Bob!" } }
15. (without introducing more risk) kubernetes examples
16. (without introducing more risk) kubernetes-anywhere
17. (without introducing more risk) Gareth Rushgrove Jsonnet functions function(cfg) local if_enabled(addon, manifest) = if cfg.phase3[addon] then manifest local join(arr) = std.foldl(function(a, b) a + b, arr, {}); if_enabled("run_addons", join([ if_enabled("kube_proxy", (import "kube-proxy/kube-proxy.jsonnet" if_enabled("dashboard", (import "dashboard/dashboard.jsonnet")(c if_enabled("heapster", (import "heapster/heapster.jsonnet")(cfg) if_enabled("kube_dns", (import "kube-dns/kube-dns.jsonnet")(cfg) ]))
18. (without introducing more risk) A REPL for Kubernetes Kubeplay
19. (without introducing more risk) errordeveloper/kubeplay
20. (without introducing more risk) Gareth Rushgrove A REPL for Kubernetes $ ./kubeplay kubeplay (namespace="*")> pods # list pods in the cluster <list-of-pods> kubeplay (namespace="*")> @pod = _.any # pick a random pod from the list kubeplay (namespace="*")> puts @pod.to_json # output the pod definition { "metadata": { ... }, "spec": { ... "containers": [ {
21. (without introducing more risk) Gareth Rushgrove Ruby based DSL @metadata = replicasets("*/").to_ruby.items.map do |k,v| v.metadata end @metadata.each do |i| puts "Name:\t#{i.name}" puts "Labels:\t#{i.labels}" puts end
22. (without introducing more risk) Declarative Domain Specific Language Puppet
23. (without introducing more risk) garethr/garethr-kubernetes
24. (without introducing more risk) Gareth Rushgrove Puppet DSL kubernetes_pod { 'sample-pod': ensure => present, metadata => { namespace => 'default', }, spec => { containers => [{ name => 'container-name', image => 'nginx', }] }, }
25. (without introducing more risk) Gareth Rushgrove Query existing resources $ 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',
26. (without introducing more risk) More Domain Specific Language Terraform
27. (without introducing more risk) maxmanuylov/terraform-provider-kubernetes
28. (without introducing more risk) Gareth Rushgrove Terraform provider resource "kubernetes_resource" "mypod" { # Required, must link on the corresponding "kubernetes_cluster" data s cluster = "${data.kubernetes_cluster.main.cluster}" collection = "pods" name = "mypod" labels { a = "b" } }
29. (without introducing more risk) If you’re interested in this topic One last thing
30. (without introducing more risk) KubeCon BoF session
31. (without introducing more risk) Questions? And thanks for listening