Shulou(Shulou.com)06/03 Report--

charts编写介绍开始

快速创建一个chart模板,helm create mychart,执行命令后本地生成一个mychart目录.

chart目录结构Chart.yaml: 该chart的描述文件,包括ico地址,版本信息等vakues.yaml: 给模板文件使用的变量charts: 依赖其他包的charts文件requirements.yaml: 依赖的chartsREADME.md: 开发人员自己阅读的文件templates: 存放k8s模板文件目录NOTES.txt 说明文件,helm install之后展示给用户看的内容deployment.yaml 创建k8s资源的yaml文件_helpers.tpl: 下划线开头的文件,可以被其他模板引用.

一个最小的chart目录,只需要包含一个Chart.yaml,和templates目录下一个k8s资源文件.如:

# mychart/Chart.yaml apiVersion: v1 appVersion: 2.9.0 version: 1.1.1 # mychart/templates/configmap.yaml apiVersion: v1 kind: ConfigMap metadata: name: mychart-configmap data: myvalue: "Hello World"helm的模板语法实现原理:- go-template双- sprighelm模板语法

模板引用方式,{{ .Release.Name }}, 通过双括号注入,小数点开头表示从最顶层命名空间引用.

helm内置对象# Release, release相关属性# Chart, Chart.yaml文件中定义的内容# Values, values.yaml文件中定义的内容模板中使用管道apiVersion: v1kind: ConfigMapmetadata: name: {{ .Release.Name }}-configmapdata: myvalue: "Hello World" drink: {{ .Values.favorite.drink | repeat 5 | quote }} food: {{ .Values.favorite.food | upper | quote }}if语句{{ if PIPELINE }}# Do something{{ else if OTHER PIPELINE }}# Do something else{{ else }}# Default case{{ end }}

操作符, and/eq/or/not

{{/* include the body of this if statement when the variable .Values.fooString exists and is set to "foo" */}}{{ if and .Values.fooString (eq .Values.fooString "foo") }} {{ ... }}{{ end }}{{/* do not include the body of this if statement because unset variables evaluate to false and .Values.setVariable was negated with the not function. */}}{{ if or .Values.anUnsetVariable (not .Values.aSetVariable) }} {{ ... }}{{ end }}控制语句块在渲染后生成模板会多出空行,需要使用{{- if ...}}的方式消除此空行.如:apiVersion: v1kind: ConfigMapmetadata: name: {{ .Release.Name }}-configmapdata: myvalue: "Hello World" {{- if eq .Values.favorite.drink "coffee"}} mug: true {{- end}}引入相对命名空间,with命令:apiVersion: v1kind: ConfigMapmetadata: name: {{ .Release.Name }}-configmapdata: myvalue: "Hello World" {{- with .Values.favorite }} drink: {{ .drink | default "tea" | quote }} food: {{ .food | upper | quote }} {{- end }}

range命令实现循环,如:

# values.yamlfavorite: drink: coffee food: pizzapizzaToppings: - mushrooms - cheese - peppers - onions#configmap.yamlapiVersion: v1kind: ConfigMapmetadata: name: {{ .Release.Name }}-configmapdata: myvalue: "Hello World" toppings: |- {{- range .Values.pizzaToppings }} - {{ . }} # .表示range的命令空间下的取值 {{- end }} {{- range $key, $val := .Values.favorite }} {{ $key }}: {{ $val | quote }} {{- end}} 变量赋值ApiVersion: v1Kind: ConfigMapMetadata: name: {{ .Release.Name }}-configmapData: myvalue: "Hello World" # 由于下方的with语句引入相对命令空间,无法通过.Release引入,提前定义relname变量 {{- $relname := .Release.Name -}} {{- with .Values.favorite }} food: {{ .food }} release: {{ $relname }} # 或者可以使用$符号,引入全局命名空间 release: {{ $.Release.Name }} {{- end }}

公共模板,define定义,template引入,在templates目录中默认下划线_开头的文件为公共模板(_helpers.tpl)

# _helpers.tpl文件{{- define "mychart.labels" }} labels: generator: helm date: {{ now | htmlDate }}{{- end }}# configmap.yaml文件apiVersion: v1kind: ConfigMapmetadata: name: {{ .Release.Name }}-configmap {{- template "mychart.labels" }}data: myvalue: "Hello World"

template语句的升级版本include,template是语句无法在后面接管道符来对引入变量做定义,

include实现了此功能.

# _helpers.tpl文件{{- define "mychart.app" -}}app_name: {{ .Chart.Name }}app_version: "{{ .Chart.Version }}+{{ .Release.Time.Seconds }}"{{- end -}}# configmap.yamlapiVersion: v1kind: ConfigMapmetadata: name: {{ .Release.Name }}-configmap labels: {{- include "mychart.app" . | nindent 4 }}data: myvalue: "Hello World" {{- range $key, $val := .Values.favorite }} {{ $key }}: {{ $val | quote }} {{- end }} {{- include "mychart.app" . | nindent 2 }}# 如果使用template只能手动空格,不能使用管道后的nindent函数来做缩进一个坑helm install stable/drupal --set image=my-registry/drupal:0.1.0 --set livenessProbe.exec.command=[cat,docroot/CHANGELOG.txt] --set livenessProbe.httpGet=null,livenessProbe在values.yaml中定义了httpGet,需要手动设置为null,然后设置exec的探针.

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