Introduction to kustomize

A talk at Kubernetes Meetup Tokyo #12
https://k8sjp.connpass.com/event/90631/

Transcript

1. Introduction to kustomize Kubernetes Meetup Tokyo #12, Jul 11, 2018
2. @spesnova SRE at Mercari, Inc. / Kubernetes Tokyo Community Organizer
3. Agenda
4. 1. Basics 2. Features 3. Keys
5. Tested with kustomize v1.0.3
6. Basics
7. What is kustomize?
8. kustomize is a command line tool
9. kustomize is a CLI for managing k8s style object with declarative way
10. Let’s learn a basic usage!
11. Basics / Hello World
12. • 3 environments (dev, stg, prod) • 1 deployment resource • different replicas by environments Example Requirements
13. hello-world/ ├── base │ ├── deployment.yaml │ └── kustomization.yaml └── overlays ├── production │ ├── replica_count.yaml │ └── kustomization.yaml └── staging ├── replica_count.yaml └── kustomization.yaml File Structure
14. hello-world/ ├── base │ ├── deployment.yaml │ └── kustomization.yaml └── overlays ├── production │ ├── replica_count.yaml │ └── kustomization.yaml └── staging ├── replica_count.yaml └── kustomization.yaml File Structure
15. hello-world/ ├── base │ ├── deployment.yaml │ └── kustomization.yaml └── overlays ├── production │ ├── replica_count.yaml │ └── kustomization.yaml └── staging ├── replica_count.yaml └── kustomization.yaml File Structure
16. hello-world/ ├── base │ ├── deployment.yaml │ └── kustomization.yaml └── overlays ├── production │ ├── replica_count.yaml │ └── kustomization.yaml └── staging ├── replica_count.yaml └── kustomization.yaml File Structure
17. hello-world/ ├── base │ ├── deployment.yaml │ └── kustomization.yaml └── overlays ├── production │ ├── replica_count.yaml │ └── kustomization.yaml └── staging ├── replica_count.yaml └── kustomization.yaml Base
18. # hello-world/base/deployment.yaml apiVersion: apps/v1 kind: Deployment metadata: name: hello-world spec: replicas: 1 selector: matchLabels: app: hello-world template: .. Base
19. # hello-world/base/kustomization.yaml resources: - deployment.yaml Base
20. hello-world/ ├── base │ ├── deployment.yaml │ └── kustomization.yaml └── overlays ├── production │ ├── replica_count.yaml │ └── kustomization.yaml └── staging ├── replica_count.yaml └── kustomization.yaml Staging
21. # hello-world/staging/replica_count.yaml apiVersion: apps/v1 kind: Deployment metadata: name: hello-world spec: replicas: 3 Staging
22. # hello-world/staging/kustomization.yaml bases: - ../../base patches: - replica_count.yaml Staging
23. $ kustomize build -h Print current configuration per contents of kustomization.yaml Usage: kustomize build [path] [flags] $ kustomize build
24. $ kustomize build hello-world/overlays/staging/ Print staging configuration
25. apiVersion: apps/v1 kind: Deployment metadata: name: hello-world spec: replicas: 3 selector: matchLabels: app: hello-world template: .. Print staging configuration
26. template-free customization
27. overlay customization
28. base deployment (replicas 1)
29. staging deployment (replicas: 3)
30. overlayed staging deployment (replicas 3)
31. hello-world/ ├── base │ ├── deployment.yaml │ └── kustomization.yaml └── overlays ├── production │ ├── replica_count.yaml │ └── kustomization.yaml └── staging ├── replica_count.yaml └── kustomization.yaml Production
32. # hello-world/production/replica_count.yaml apiVersion: apps/v1 kind: Deployment metadata: name: hello-world spec: replicas: 7 Production
33. # hello-world/production/kustomization.yaml bases: - ../../base patches: - replica_count.yaml Production
34. $ kustomize build hello-world/overlays/production/ Print production configuration
35. apiVersion: apps/v1 kind: Deployment metadata: name: hello-world spec: replicas: 7 selector: matchLabels: app: hello-world template: .. Print production configuration
36. $ kustomize build [PATH] | kubectl apply -f - Apply printed configuration
37. Basics / Motivation
38. Declarative specification is the recommended way
39. However…
40. It’s difficult to use only current kubectl to follow declarative way…
41. Then…
42. • Helm • Ksonnet • Kapitan • Forge • Ktmpl • etc… Another Tools are required
43. 1. I have to learn new tools… 2. I have to learn new DSL… (complicated!) 3. I have to teach new concepts to teams… Drawbacks of those tools
44. Features
45. Features / Name Prefix
46. # overlays/production/kustomization.yaml namePrefix: prod- bases: - ../../base patches: - replica_count.yaml Name Prefix
47. $ kustomize build hello-world/overlays/production/ Name Prefix
48. apiVersion: apps/v1 kind: Deployment metadata: name: prod-hello-world spec: replicas: 7 selector: matchLabels: app: hello-world template: .. Name Prefix
49. Features / Common Labels
50. # base/kustomization.yaml commonLabels: owner: spesnova resources: - deployment.yaml Common Labels
51. $ kustomize build hello-world/overlays/production/ Common Labels
52. apiVersion: apps/v1 kind: Deployment metadata: name: hello-world labels: owner: spesnova spec: replicas: 7 selector: matchLabels: app: hello-world template: .. Common Labels
53. Features / Common Annotattion
54. # base/kustomization.yaml commonAnnotations: description: This is Hello World App resources: - deployment.yaml Common Annotations
55. $ kustomize build hello-world/overlays/production/ Common Annotations
56. apiVersion: apps/v1 kind: Deployment metadata: name: hello-world annotations: description: This is Hello World App spec: replicas: 7 selector: matchLabels: app: hello-world template: … Common Annotations
57. Features / ConfigMap Generator
58. # base/kustomization.yaml resources: - deployment.yaml configMapGenerator: - name: hello-config files: - hello.config ConfigMap Generator
59. # hello.config name=hello-world region=tokyo ConfigMap Generator
60. $ kustomize build hello-world/overlays/production/ ConfigMap Generator
61. apiVersion: v1 data: hello.config: | name=hello-world region=tokyo kind: ConfigMap metadata: creationTimestamp: null name: hello-config-4g5t58m8t5 --- apiVersion: apps/v1 kind: Deployment … ConfigMap Generator
62. apiVersion: v1 data: hello.config: | name=hello-world region=tokyo kind: ConfigMap metadata: creationTimestamp: null name: hello-config-4g5t58m8t5 --- apiVersion: apps/v1 kind: Deployment … Hash suffix
63. # hello.config name=hello-world region=london Hash suffix
64. apiVersion: v1 data: hello.config: | name=hello-world region=tokyo kind: ConfigMap metadata: creationTimestamp: null name: hello-config-bdmmkghm2m --- apiVersion: apps/v1 kind: Deployment … Hash suffix
65. Features / Secrets Generator (skip)
66. Features / Diff
67. $ kustomize diff hello-world/overlays/production/ $ kustomize diff
68. @@ -3,7 +3,7 @@ metadata: name: hello-world spec: - replicas: 1 + replicas: 7 selector: matchLabels: app: hello-world $ kustomize diff
69. Features / Substitute (skip)
70. Workflows / Bespoke config
71. Bespoke config
72. Workflows / Off-the-shelf config
73. Off-the-shelf config
74. Keys
75. Keys / Overlay vs Template
76. 1. Can only override parameterized config 2. DSL is too complicated for human 3. Most tools can not read DSL Drawbacks of Templating
77. 1. I’m using official Redis Helm chart 2. I want to add annotation 3. Annotations are not defined in the chart… 4. …Fork? Example
78. With kustomize You can override any part of config with kustomize
79. Keys / Single source of truth
80. 1. There is a config file “hello.config” 2. Copy contents of the file 3. Paste it into configMap 4. … I have 2 config sources… Before kustomize
81. # base/kustomization.yaml resources: - deployment.yaml configMapGenerator: - name: hello-config files: - hello.config ConfigMap Generator
82. # hello.config name=hello-world region=tokyo ConfigMap Generator
83. $ kustomize build hello-world/overlays/production/ ConfigMap Generator
84. apiVersion: v1 data: hello.config: | name=hello-world region=tokyo kind: ConfigMap metadata: creationTimestamp: null name: hello-config-4g5t58m8t5 --- apiVersion: apps/v1 kind: Deployment … ConfigMap Generator
85. 1. There is a config file “hello.config” 2. Run “kustomize build” 3. kustomize generates configMap 4. The config source is only “hello.config” After kustomize
86. Keys / Rolling ConfigMap Update
87. 1. Update contents of existing configMap 2. Deployment itself is not changed… 3. Deployment still reads old configMap… Updating existing configMap
88. apiVersion: v1 data: hello.config: | name=hello-world region=tokyo kind: ConfigMap metadata: creationTimestamp: null name: hello-config-4g5t58m8t5 --- apiVersion: apps/v1 kind: Deployment … Hash suffix
89. 1. Update contents of configMap 2. kustomize prints new configMap 3. Update configMap name in deployment 4. Deployment reads new configMap Rolling ConfigMap Update
90. Keys / Teaching native k8s APIs
91. kustomize exposes and teaches native k8s APIs, rather than hiding them. IUUQTHJUIVCDPNLVCFSOFUFTTJHTLVTUPNJ[FCMPCNBTUFSEPDTHMPTTBSZNE
92. Same as kubernetes manifest Using Native Kubernetes API
93. 1. Lower learning cost 2. Deeper understanding about Kubernetes Using Native Kubernetes API
94. Keys / Rollback
95. $ git checkout XXXXXX $ kustomize build [PATH] | kubectl apply -f - Rollback
96. kustomize rollback is very good for GitOps. However, I also like heroku style rollback such as “helm status”, “helm history”, “helm rollback”. Helm provides us logical group of k8s resources as “application”. kustomize doesn’t. Rollback
97. Kubernetes Application proposal KEP Related issue https://github.com/kubernetes/community/pull/1629
98. Keys / might be moved to kubectl
99. Kustomize was initially developed as its own cli, however once it has matured, it should be published as a subcommand of kubectl or as a statically linked plugin. IUUQTHJUIVCDPNLVCFSOFUFTDPNNVOJUZCMPCNBTUFSLFQTTJHDMJLVTUPNJ[FNEJNQMFNFOUBUJPOEFUBJMTOPUFTDPOTUSBJOUTPQUJPOBM
100. Keys / See design doc!
101. https://github.com/kubernetes/community/blob/master/contributors/ design-proposals/architecture/declarative-application- management.md IUUQTHJUIVCDPNLVCFSOFUFTDPNNVOJUZCMPCNBTUFSLFQTTJHDMJLVTUPNJ[FNEJNQMFNFOUBUJPOEFUBJMTOPUFTDPOTUSBJOUTPQUJPOBM It’s awesome!
102. It’s awesome! If kustomize looks easy to use for you, I think it comes from good design!
103. Questions
104. Can I delete labels with overlay? As far as I know, you can not for now
105. End