手把手教你写一个通用的helmchart
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成都创新互联的客户来自各行各业，为了共同目标，我们在工作上密切配合，从创业型小企业到企事业单位，感谢他们对我们的要求，感谢他们从不同领域给我们带来的挑战，让我们激情的团队有机会用头脑与智慧不断的给客户带来惊喜。专业领域包括成都网站设计、成都网站制作、电商网站开发、微信营销、系统平台开发。
1. 模板介绍
首先，放上此模板链接：
https://github.com/ygqygq2/charts/tree/master/ygqygq2/mod-chart
此chart可当作POD单image的通用模板，只需要使用sed替换下chart名，并修改下README.md和NOTES.txt就可以了。下文，我通过复制此chart成example-chart来作示范说明。
[root@master1 mod-chart]# tree
.
├── Chart.yaml # chart版本信息文件
├── README.md # chart说明文件
├── templates # kubernetes资源yaml模板
│ ├── configmap.yaml # configmap模板
│ ├── deployment-statefulset.yaml # deployment或statefulset模板
│ ├── _helpers.tpl # 辅助模板和 partials
│ ├── ingress.yaml # ingress模板
│ ├── NOTES.txt # 部署chart后输出的帮助文档
│ ├── pvc.yaml # pvc模板
│ ├── secret.yaml # secret模板
│ ├── service-headless.yaml # service headless模板
│ └── service.yaml # service模板
└── values.yaml # 默认设置
1 directory, 12 files
[root@master1 mod-chart]# helm3 lint --strict .
1 chart(s) linted, 0 chart(s) failed2. 新chart制作
注：
下文中文件内容我保留，只加注释。
注释中需要修改的地方[*]标记为必选，[-]标识为可选。
2.1 目录准备
将模板mod-chart复制成example-chart，并作内容替换。
rsync -avz mod-chart/ example-chart/
cd example-chart/
sed -i 's@mod-chart@example-chart@g' *.*
sed -i 's@mod-chart@example-chart@g' templates/*.*2.2 修改Chart.yaml
vim Chart.yaml
apiVersion: v1 # 当前helm api版本，不需要修改
appVersion: 1.14.2 # 此处为你应用程序的版本号 [*]
description: Chart for the nginx server # 介绍此chart是干嘛的，按需求修改
engine: gotpl # go模板引擎，不需要修改 [-]
name: example-chart # 模板名，对应目录名 [*]
version: 1.0.0 # 此chart版本号 [*]
home: http://www.nginx.org # 应用程序官网 [*]
icon: /upload/otherpic48/60313.jpg # 应用程序logo地址 [*]
keywords: # 关键字列表 [*]
- nginx
- http
- web
- www
- reverse proxy
maintainers: # 维护人员列表 [*]
- email: 29ygq@sina.com
name: Chinge Yang
sources: # 应用程序来源 [-]
- https://github.com/bitnami/bitnami-docker-nginx2.3 修改values.yaml
因为values.yaml设置涉及到yaml格式，yaml文件格式说明可以看这篇文章：
http://www.ruanyifeng.com/blog/2016/07/yaml.html
这里提几个常用的地方：
- 使用2个空格作缩进；
- 确认数字为字符类型时，使用双引号引起来；
- 为了迎合helm3的规范，空定义最好将相关符号补上：
string: "" list: [] map: {}
没什么特殊要求，一般需要修改的地方有image、service、healthCheck、persistentVolume.mountPaths
# Default values for mod-chart.
# This is a YAML-formatted file.
# Declare variables to be passed into your templates.
## Global Docker image parameters
## Please, note that this will override the image parameters, including dependencies, configured to use the global value
## Current available global Docker image parameters: imageRegistry and imagePullSecrets
##
global: # 设置后覆盖后面默认的镜像仓库
imageRegistry: ""
imagePullSecrets: []
# - myRegistryKeySecretName
statefulset:
enabled: false
## String to partially override fullname template (will maintain the release name)
##
nameOverride: ""
## String to fully override fullname template
##
fullnameOverride: ""
## By default deploymentStrategy is set to rollingUpdate with maxSurge of 25% and maxUnavailable of 25% .
## You can change type to `Recreate` or can uncomment `rollingUpdate` specification and adjust them to your usage.
deploymentStrategy: {}
# rollingUpdate:
# maxSurge: 25%
# maxUnavailable: 25%
# type: RollingUpdate
# 副本个数
replicaCount: 1
# 容器image及tag
image:
registry: docker.io
repository: bitnami/nginx
tag: latest
pullPolicy: IfNotPresent # IfNotPresent: 有则不拉（减少流量和操作步骤），Always: 不管tag总拉（适合tag不变时更新）
pullSecrets: []
# - private-registry-key
service:
type: ClusterIP # 一般不用修改
ingressPort: 8080
ports:
http: # 多端口暴露时，复制一段
port: 8080 # Service port number for client-a port.
protocol: TCP # Service port protocol for client-a port.
## env set
## ref: https://kubernetes.io/docs/tasks/inject-data-application/define-environment-variable-container/
env: []
# - name: DEMO_GREETING
# value: "Hello from the environment"
# - name: DEMO_FAREWELL
# value: "Such a sweet sorrow"
## command set
startCommand: []
# - "java -Xdebug -Xnoagent -Djava.compiler=NONE"
# - "-Xrunjdwp:transport=dt_socket,address=5005,server=y,suspend=n"
# - "-Djava.security.egd=file:/dev/urandom"
# - "-jar /test.jar"
# - "-Duser.timezone=GMT+08"
## Enable configmap and add data in configmap
config:
enabled: false
subPath: ""
mountPath: /conf
data: {}
############################# 示例 ####################################
## 以下示例，挂载文件至 /conf/app.conf
# enabled: true
# mountPath: /conf/app.conf
# subPath: app.conf # 使用subPath时，上面mountPath路径写文件完整绝对路径
# data:
# app.conf: |-
# appname = example-chart
## 以下示例，挂载多个文件至 /conf/ 下
# enabled: true
# mountPath: /conf # 不使用subPath
# data:
# app.conf: |-
# appname = example-chart
# bpp.conf: |-
# bppname
#
## 挂载多个文件至多个不同路径，需要相应修改 templates/deployment-statefulset.yaml
############################# 示例 ####################################
## To use an additional secret, set enable to true and add data
## 用法同上，不另作说明
secret:
enabled: false
mountPath: /etc/secret-volume
subPath: ""
readOnly: true
data: {}
## liveness and readiness
## ref: https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-probes/
healthCheck:
enabled: true
type: tcp # http/tcp
port: http # 健康检查的端口名或端口
httpPath: '/' # http时必须设置
livenessInitialDelaySeconds: 10 # 初始延迟秒数
livenessPeriodSeconds: 10 # 检测周期，默认值10，最小为1
readinessInitialDelaySeconds: 10 # 初始延迟秒数
readinessPeriodSeconds: 10 # 检测周期，默认值10，最小为1
resources: {}
# 容器资源设置
# We usually recommend not to specify default resources and to leave this as a conscious
# choice for the user. This also increases chances charts run on environments with little
# resources, such as Minikube. If you do want to specify resources, uncomment the following
# lines, adjust them as necessary, and remove the curly braces after 'resources:'.
# limits:
# cpu: 100m
# memory: 128Mi
# requests:
# cpu: 100m
# memory: 128Mi
## Node labels and tolerations for pod assignment
### ref: https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#nodeselector
### ref: https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#taints-and-tolerations-beta-feature
labels: {}
podAnnotations: {}
nodeSelector: {}
tolerations: []
affinity: {}
annotations: {}
## Enable persistence using Persistent Volume Claims
## ref: http://kubernetes.io/docs/user-guide/persistent-volumes/
##
persistentVolume: # 是否存储持久化
enabled: false
## If defined, storageClassName:
## If set to "-", storageClassName: "", which disables dynamic provisioning
## If undefined (the default) or set to null, no storageClassName spec is
## set, choosing the default provisioner. (gp2 on AWS, azure-disk on
## Azure, standard on GKE, AWS & OpenStack)
##
storageClass: "-"
accessMode: ReadWriteOnce
annotations: {}
# helm.sh/resource-policy: keep
size: 1Gi # 大小
existingClaim: {} # 使用已存在的pvc
mountPaths: []
# - name: data-storage
# mountPath: /config
# subPath: config # 多个路径使用同一个pvc使用subPath，用法同上面config中示例说明
# - name: data-storage
# mountPath: /data
# subPath: data
ingress: # 是否使用nginx暴露域名或端口
enabled: false
annotations: {}
# kubernetes.io/ingress.class: nginx
# kubernetes.io/tls-acme: "true"
path: /
hosts:
- chart-example.local
tls: []
# - secretName: chart-example-tls
# hosts:
# - chart-example.local
## Add init containers. e.g. to be used to give specific permissions for data
## Add your own init container or uncomment and modify the given example.
initContainers: []
## Prometheus Exporter / Metrics
##
metrics:
enabled: false
image:
registry: docker.io
repository: nginx/nginx-prometheus-exporter
tag: 0.1.0
pullPolicy: IfNotPresent
## Optionally specify an array of imagePullSecrets.
## Secrets must be manually created in the namespace.
## ref: https://kubernetes.io/docs/tasks/configure-pod-container/pull-image-private-registry/
##
pullSecrets: []
# - myRegistrKeySecretName
## Metrics exporter pod Annotation and Labels
podAnnotations:
# prometheus.io/scrape: "true"
# prometheus.io/port: "9113"
## Metrics exporter resource requests and limits
## ref: http://kubernetes.io/docs/user-guide/compute-resources/
##
resources: {}
## Uncomment and modify this to run a command after starting the core container.
## ref: https://kubernetes.io/docs/concepts/containers/container-lifecycle-hooks/
lifecycle: {}
# preStop:
# exec:
# command: ["/bin/bash","/pre-stop.sh"]
# postStart:
# exec:
# command: ["/bin/bash","/post-start.sh"]
## Deployment additional volumes.
deployment:
additionalVolumes: []
## init containers
## ref: https://kubernetes.io/docs/concepts/workloads/pods/init-containers/
## Add init containers. e.g. to be used to give specific permissions for data
## Add your own init container or uncomment and modify the given example.
initContainers: {}
# - name: fmp-volume-permission
# image: busybox
# imagePullPolicy: IfNotPresent
# command: ['chown','-R', '200', '/extra-data']
# volumeMounts:
# - name: extra-data
# mountPath: /extra-data
## Additional containers to be added to the core pod.
additionalContainers: {}
# - name: my-sidecar
# image: nginx:latest
# - name: lemonldap-ng-controller
# image: lemonldapng/lemonldap-ng-controller:0.2.0
# args:
# - /lemonldap-ng-controller
# - --alsologtostderr
# - --configmap=$(POD_NAMESPACE)/lemonldap-ng-configuration
# env:
# - name: POD_NAME
# valueFrom:
# fieldRef:
# fieldPath: metadata.name
# - name: POD_NAMESPACE
# valueFrom:
# fieldRef:
# fieldPath: metadata.namespace
# volumeMounts:
# - name: copy-portal-skins
# mountPath: /srv/var/lib/lemonldap-ng/portal/skins 2.4 修改README.md和templates/NOTES.txt
根据 values.yaml中的默认设置相应修改README.md，内容使用markdown语法，这里不作详细说明。templates/NOTES.txt是部署chart后输出的帮助文档，里面支持go template语法。模板里已经写成了非常通用。必要情况下，适当按应用需求来修改，这样会显得部署后提示非常友好和人性化。
2.5 templates下yaml简要说明
templates目录下为kubernetes资源yaml文件模板，以资源名命名文件名，复杂些的可以加上资源功能或者模块名等。
templates/secret.yaml
{{- if .Values.secret.enabled }} # if用法。语法代码注意形成一致缩进习惯，便于阅读
apiVersion: v1
kind: Secret
metadata:
name: {{ template "example-chart.fullname" . }} # 使用辅助模板时，点号可用 $ 代替，特别是在range下
labels:
app: {{ template "example-chart.name" . }}
chart: {{ template "example-chart.chart" . }}
release: "{{ .Release.Name }}"
heritage: "{{ .Release.Service }}"
{{- if .Values.labels }}
{{ toYaml .Values.labels | indent 4 }} # 使用toYaml时，不缩进，indent接空格数
{{- end }}
data:
{{- range $key, $value := .Values.secret.data }} # range用法
{{ $key }}: {{ $value | b64enc | quote }} # secret中value注意使用base64转换
{{- end }}
{{- end }}templates/deployment-statefulset.yaml
{{- if .Values.statefulset.enabled }} # 判断使用deployment和statefulset资源api类型
apiVersion: apps/v1
kind: StatefulSet
{{- else }}
apiVersion: apps/v1
kind: Deployment
{{- end }}
metadata:
name: {{ template "example-chart.fullname" . }}
labels:
app: {{ template "example-chart.name" . }}
chart: {{ template "example-chart.chart" . }}
release: {{ .Release.Name }}
heritage: {{ .Release.Service }}
{{- if .Values.labels }} # 额外的标签
{{ toYaml .Values.labels | indent 4 }}
{{- end }}
{{- if .Values.annotations }} # 自定义注释
annotations:
{{ toYaml .Values.annotations | indent 4 }}
{{- end }}
spec:
replicas: {{ .Values.replicaCount }} # 副本数
{{- if .Values.statefulset.enabled }} # statefulset需要定义serviceName
serviceName: {{ template "example-chart.fullname" . }}-headless
{{- end }}
{{- if .Values.deploymentStrategy }}
strategy:
{{ toYaml .Values.deploymentStrategy | indent 4 }}
{{- end }}
selector:
matchLabels:
app: {{ template "example-chart.name" . }}
release: {{ .Release.Name }}
template:
metadata:
annotations:
{{- if .Values.podAnnotations }}
{{ toYaml .Values.podAnnotations | indent 8 }}
{{- end }}
{{- if .Values.metrics.podAnnotations }}
{{ toYaml .Values.metrics.podAnnotations | indent 8 }}
{{- end }}
labels:
app: {{ template "example-chart.name" . }}
release: {{ .Release.Name }}
spec:
{{- include "example-chart.imagePullSecrets" . | indent 6 }}
{{- if .Values.initContainers }}
initContainers:
{{ toYaml .Values.initContainers | indent 8 }}
{{- end }}
nodeSelector:
{{ toYaml .Values.nodeSelector | indent 8 }}
affinity:
{{ toYaml .Values.affinity | indent 8 }}
tolerations:
{{ toYaml .Values.tolerations | indent 8 }}
containers:
{{- if .Values.metrics.enabled }} # metrics容器可根据需求修改
- name: metrics
image: {{ template "metrics.image" . }}
imagePullPolicy: {{ .Values.metrics.image.pullPolicy | quote }}
command: [ '/usr/bin/exporter', '-nginx.scrape-uri', 'http://127.0.0.1:8080/status']
ports:
- name: metrics
containerPort: 9113
livenessProbe:
httpGet:
path: /metrics
port: metrics
initialDelaySeconds: 15
timeoutSeconds: 5
readinessProbe:
httpGet:
path: /metrics
port: metrics
initialDelaySeconds: 5
timeoutSeconds: 1
resources:
{{ toYaml .Values.metrics.resources | indent 12 }}
{{- end }}
- name: {{ .Chart.Name }}
image: {{ template "example-chart.image" . }}
imagePullPolicy: {{ .Values.image.pullPolicy | quote }}
{{- if .Values.lifecycle }}
lifecycle:
{{ toYaml .Values.lifecycle | indent 12 }}
{{- end }}
{{- if .Values.startCommand }}
command:
{{ toYaml .Values.startCommand |indent 12 }}
{{- end }}
env:
{{ toYaml .Values.env | indent 12 }}
resources:
{{ toYaml .Values.resources | indent 12 }}
ports:
{{- range $key, $value := .Values.service.ports }}
- name: {{ $key }}
containerPort: {{ $value.port }}
protocol: {{ $value.protocol }}
{{- end }}
{{- if .Values.healthCheck.enabled }}
livenessProbe:
{{- if eq .Values.healthCheck.type "http" }}
httpGet:
path: {{ .Values.healthCheck.httpPath }}
port: {{ .Values.healthCheck.port }}
{{- else }}
tcpSocket:
port: {{ .Values.healthCheck.port }}
{{- end }}
initialDelaySeconds: {{ .Values.healthCheck.livenessInitialDelaySeconds }}
periodSeconds: {{ .Values.healthCheck.livenessPeriodSeconds }}
readinessProbe:
{{- if eq .Values.healthCheck.type "http" }}
httpGet:
path: {{ .Values.healthCheck.httpPath }}
port: {{ .Values.healthCheck.port }}
{{- else }}
tcpSocket:
port: {{ .Values.healthCheck.port }}
{{- end }}
initialDelaySeconds: {{ .Values.healthCheck.readinessInitialDelaySeconds }}
periodSeconds: {{ .Values.healthCheck.readinessPeriodSeconds }}
{{- end }}
volumeMounts: # 容器挂载点
{{- if .Values.config.enabled }}
- name: {{ template "example-chart.name" . }}-conf
mountPath: {{ .Values.config.mountPath }}
subPath: {{ .Values.config.subPath }}
{{- end }}
{{- if .Values.secret.enabled }}
- name: {{ template "example-chart.name" . }}-secret
mountPath: {{ .Values.secret.mountPath }}
subPath: {{ .Values.secret.subPath }}
readOnly: {{ .Values.secret.readOnly }}
{{- end }}
{{- if .Values.persistentVolume.mountPaths }}
{{ toYaml .Values.persistentVolume.mountPaths | indent 12 }}
{{- end }}
{{- if .Values.additionalContainers }}
{{ toYaml .Values.additionalContainers | indent 8 }}
{{- end }}
volumes: # volume名需要和上文volumeMounts中的名字一一对应
{{- if .Values.config.enabled }}
- name: {{ template "example-chart.name" . }}-conf
configMap:
name: {{ template "example-chart.fullname" . }}
{{- end }}
{{- if .Values.secret.enabled }}
- name: {{ template "example-chart.name" . }}-secret
secret:
secretName: {{ template "example-chart.fullname" . }}
{{- end }}
{{- if .Values.deployment.additionalVolumes }}
{{ toYaml .Values.deployment.additionalVolumes | indent 8 }}
{{- end }}
{{- if not .Values.statefulset.enabled }}
{{- if .Values.persistentVolume.enabled }}
- name: data-storage
persistentVolumeClaim:
claimName: {{ .Values.persistentVolume.existingClaim | default (include "example-chart.fullname" .) }}
{{- else }}
- name: data-storage
emptyDir: {}
{{- end }}
{{- else }}
{{- if .Values.persistentVolume.enabled }}
volumeClaimTemplates:
- metadata:
name: data-storage
labels:
app: {{ template "example-chart.name" . }}
chart: {{ template "example-chart.chart" . }}
release: {{ .Release.Name }}
heritage: {{ .Release.Service }}
spec:
accessModes:
- {{ .Values.persistentVolume.accessMode | quote }}
annotations:
{{- range $key, $value := $.Values.persistentVolume.annotations }}
{{ $key }}: {{ $value }}
{{- end }}
resources:
requests:
storage: {{ .Values.persistentVolume.size }}
{{- if .Values.persistentVolume.storageClass }}
{{- if (eq "-" .Values.persistentVolume.storageClass) }}
storageClassName: ""
{{- else }}
storageClassName: "{{ .Values.persistentVolume.storageClass }}"
{{- end }}
{{- end }}
{{- else }}
- name: data-storage
emptyDir: {}
{{- end }}
{{- end -}}3. 小结
以上yaml中未作详细说明，仔细看其内容都能明白大致意思。以下是对于helm chart新手的一些建议：
- 刚接触helm chart时，多模仿stable和bianami中charts的写法，特别是
values.yaml和templates目录中的一些设计，差不多都已经非常统一了。这样遇到自己有相似需求，可直接使用相应的功能块，写出来的chart也显得非常专业。 - 使用chart时，最好使用
helm命令fetch下来，大概读一遍其chart内容，这样看多了，自然就越来越熟悉，而且出错时，也便于自己排查问题。
参考资料：
[1] https://helm.sh/
[2] https://whmzsu.github.io/helm-doc-zh-cn/
本文标题：手把手教你写一个通用的helmchart
标题来源：http://myzitong.com/article/ggpdcd.html