k8s配置管理kustomize实践

$ kubectl help kustomize
Print a set of API resources generated from instructions in a kustomization.yaml file.

 The argument must be the path to the directory containing the file, or a git repository URL with a path suffix
specifying same with respect to the repository root.

 kubectl kustomize somedir

Examples:
  # Use the current working directory
  kubectl kustomize .

  # Use some shared configuration directory
  kubectl kustomize /home/configuration/production

  # Use a URL
  kubectl kustomize github.com/kubernetes-sigs/kustomize.git/examples/helloWorld?ref=v1.0.6

Usage:
  kubectl kustomize <dir> [flags] [options]

kubectl kustomize <dir> | kubectl apply -f -

resources:
- deployment.yaml

bases:
- ../base # 模板base文件夹的路径
patches:
- deployment_patches.yaml # 补丁文件路径
``` 

overlay 主要是对 base 做覆写（所以才叫 overlay 啊~）

![](/img/kubernetes实战/kustomize-overlay.jpg)

kustomization 打补丁是通过 `kind`和`name`进行匹配的，也就是 base 和 patch 里面的名字和类型一致就可以匹配。

这里要注意，对于 deployment 中的 `template/containers` 的下面也是一种类型（本质是容器），所以这的名字也是要一致的，不然会报错。

## kustomize 语法

除了上面提到的两种基本语法 `resources`、`base` 和 `patches`，常用到的语法还有：
- configMapGenerator
- secretGenerator
- generatorOptions
- commonLabels
- commonAnnonation
- namespace
- images
- namePrefix
- nameSuffix
- images


### configMapGenerator

用于生成configMap配置文件的，用法：
```YAML
configMapGenerator:
- name: my-application-properties # configMap名字
  files:
  - application.properties # 本地文件路径

configMapGenerator:
- name: my-java-server-env-vars
  literals:
  - JAVA_HOME=/opt/java/jdk
  - JAVA_TOOL_OPTIONS=-agentlib:hprof

generatorOptions:
  labels: # 为所有 generator 设置 labels 属性
    fruit: apple
  annotations: # 为所有 generator 设置 annotations 属性
    kustomize.generated.resource: somevalue
  disableNameSuffixHash: true # 关闭名字前缀的hash，默认是开启hash，因此generator在内容相同不同的时候名字会不一样

commonLabels:
  app: foo
  environment: test
resources:
- deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: foo # 新加或覆盖的label
    environment: test # 新加或覆盖的label
    ... 模板自带没被覆盖的label
  name: nginx-deployment
spec:
  selector:
    matchLabels:
    app: foo # 新加或覆盖的label
    environment: test # 新加或覆盖的label
    ... 模板自带没被覆盖的label
  template:
    metadata:
      labels:
        app: foo # 新加或覆盖的label
        environment: test # 新加或覆盖的label
        ... 模板自带没被覆盖的label
    spec:
      containers:
      - image: nginx
        name: nginx

namePrefix: prod- # 添加前缀的字段

images:
  - name: mycontainerregistry/myimage # 需修改的原镜像名称（不用带版本）
    newName: differentregistry/myimage # 新的镜像名称
    newTag: v1 # 新的镜像版本

replicas:
- name: deployment-name
  count: 5

patches:
- path: patch.yaml # patch 文件路径

patches:
- path: patch.yaml
  target:
    group: apps
    version: v1
    kind: Deployment
    name: deploy.*
    labelSelector: "env=dev"
    annotationSelector: "zone=west"

containers:
  - image: myimage
    command: ["start", "--host", "$(MY_SERVICE_NAME)"]
    env:
    - name: SECRET_TOKEN
      value: $(SOME_SECRET_NAME)

vars:
- name: SOME_SECRET_NAME
  objref:
    kind: Secret
    name: my-secret
    apiVersion: v1
- name: MY_SERVICE_NAME
  objref:
    kind: Service
    name: my-service
    apiVersion: v1
  fieldref:
    fieldpath: metadata.name