helm3 chart开发

安装helm3

#wget https://docs.rancher.cn/download/helm/helm-v3.3.0-linux-amd64.tar.gz 
wget https://get.helm.sh/helm-v3.9.2-linux-amd64.tar.gz  #下载helm安装包

tar -zxvf helm-v3.3.0-linux-amd64.tar.gz #解压安装包
cp linux-amd64/helm /usr/local/bin/

helm version #检验是否安装成功


helm自动补全

source <(helm completion bash)
echo "source <(helm completion bash)" >> ~/.bashrc
source ~/.bashrc

helm常用命令

命令	用法	描述
create	helm create NAME [flags]	create a new chart with the given name
install	helm install [NAME] [CHART] [flags]	installs a chart
pull	helm pull [chart URL |repo/chartname] [...] [flags]	download a chart from a repository and (optionally) unpack it in local directory
repo	helm repo ...	add, list, remove, update, and index chart repositories
search	helm search [command] ( repo/hub )	search for a keyword in charts
uninstall	helm uninstall RELEASE_NAME [...] [flags]	uninstall a release
upgrade	helm upgrade [RELEASE] [CHART] [flags]	upgrade a release

创建chart包

helm create httpbin  #创建httpbin chart

查看httpbin的目录结构

sudo apt install tree #安装tree

tree httpbin -a
httpbin
├── charts
├── Chart.yaml
├── .helmignore
├── templates
│   ├── deployment.yaml
│   ├── _helpers.tpl
│   ├── ingress.yaml
│   ├── NOTES.txt
│   ├── serviceaccount.yaml
│   ├── service.yaml
│   └── tests
│       └── test-connection.yaml
└── values.yaml

3 directories, 10 files

Chart包文件结构

Helm规范了Chart的目录和文件结构，这些目录或者文件都有确定的用途。

• charts/，包含其它Chart，称之为Sub Chart，或者依赖Chart。
• Chart.yaml，包含Chart的说明，可在从模板中访问Chart定义的值。
• .helmignore，定义了在helm package时哪些文件不会打包到Chart包tgz中。
• ci/，缺省没有该目录，持续集成的一些脚本。
• templates/，用于放置模板文件，主要定义提交给Kubernetes的资源yaml文件。安装Chart时，Helm会根据chart.yaml、values.yam以及命令行提供的值对Templates进行渲染，最后会将渲染的资源提交给Kubernetes。
• _helpers.tpl，定义了一些可重用的模板片断，此文件中的定义在任何资源定义模板中可用。
• NOTES.txt，提供了安装后的使用说明，在Chart安装和升级等操作后，
• tests/，包含了测试用例。测试用例是pod资源，指定一个的命令来运行容器。容器应该成功退出（exit 0），测试被认为是成功的。该pod定义必须包含helm测试hook注释之一：helm.sh/hook: test-success或helm.sh/hook: test-failure。
• values.yaml，values文件对模板很重要，该文件包含Chart默认值。Helm渲染template时使用这些值

修改values.yaml

修改values.yaml如下,用于Helm渲染template

• 将镜像改为image.repository=docker.io/kennethreitz/httpbin。
• 不创建serviceAccount，serviceAccount.create=false
• 为了Kubernetes集群外能访问Service，将type改为NodePort。并增加一个参数，为nodePort配置一个固定端口

cd httpbin/
vi values.yaml

# Default values for httpbin.
# This is a YAML-formatted file.
# Declare variables to be passed into your templates.

replicaCount: 1

image:
  repository: docker.io/kennethreitz/httpbin  #修改镜像为httpbin
  pullPolicy: IfNotPresent
  # Overrides the image tag whose default is the chart appVersion.
  tag: latest

imagePullSecrets: []
nameOverride: ""
fullnameOverride: ""

serviceAccount:
  # Specifies whether a service account should be created
  create: false  #不创建serviceAccount,改为false
  # Annotations to add to the service account
  annotations: {}
  # The name of the service account to use.
  # If not set and create is true, a name is generated using the fullname template
  name: ""

podAnnotations: {}

podSecurityContext: {}
  # fsGroup: 2000

securityContext: {}
  # capabilities:
  #   drop:
  #   - ALL
  # readOnlyRootFilesystem: true
  # runAsNonRoot: true
  # runAsUser: 1000

service:
  type: NodePort  #将type改为NodePort
  port: 80
  nodePort: 30080    #为NodePort配置一个固定端口


ingress:
  enabled: false
  annotations: {}
    # kubernetes.io/ingress.class: nginx
    # kubernetes.io/tls-acme: "true"
  hosts:
    - host: chart-example.local
      paths: []
  tls: []
  #  - secretName: chart-example-tls
  #    hosts:
  #      - chart-example.local

resources: {}
  # 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

autoscaling:
  enabled: false
  minReplicas: 1
  maxReplicas: 100
  targetCPUUtilizationPercentage: 80
  # targetMemoryUtilizationPercentage: 80

nodeSelector: {}

tolerations: []

affinity: {}

修改service.yaml

由于配置了固定的nodePort，所以在service.yaml中增加该参数，并引用了对应的value值

vi templates/service.yaml
apiVersion: v1
kind: Service
metadata:
  name: {{ include "httpbin.fullname" . }}
  labels:
    {{- include "httpbin.labels" . | nindent 4 }}
spec:
  type: {{ .Values.service.type }}
  ports:
    - port: {{ .Values.service.port }}
      targetPort: http
      protocol: TCP
      name: http
      nodePort: {{ .Values.service.nodePort }}  #新增参数
  selector:
    {{- include "httpbin.selectorLabels" . | nindent 4 }}

查看渲染后结果

helm template my-release httpbin


安装httpbin

渲染没有问题后开始安装httpbin

helm install my-release httpbin


访问httpbin

kubectl get pod #观察httpbin是否部署成功


访问 http://IP:30080

打包chart

部署成功后可将chart进行打包

helm package httpbin