Helm V3 基本使用

1、部署Helm客户端

Helm客户端下载地址: https://github.com/helm/helm/releases 解压移动到 /usr/bin/ 目录即可。

wget https://get.helm.sh/helm-v3.8.1-linux-amd64.tar.gz
tar zxvf helm-v3.8.1-linux-amd64.tar.gz
mv linux-amd64/helm /usr/bin/

2、Helm 常用命令

命令	描述
create	创建一个chart并指定名字
install	安装一个chart
uninstall	卸载一个release
upgrade	更新一个release
rollback	回滚之前版本
version	查看helm客户端版本
dependency	管理chart依赖
get	下载一个release。可用子命令：all、hooks、manifest、notes、values
history	获取release历史
list	列出release
package	将chart目录打包到chart存档文件中
pull	从远程仓库中下载chart并解压到本地 # helm pull stable/mysql --untar
repo	添加，列出，移出，更新和索引chart仓库。可用子命令：add、index、list、remove、update
search	根据关键字搜索chart。可用子命令：hub、repo
show	查看chart详细信息。可用子命令：all、chart、readme、values
status	显示已命名版本的状态
template	本地呈现模板

3、配置国内chart仓库

• 微软仓库 (http://mirror.azure.cn/kubernetes/charts/) 推荐此仓库，基本上官网有的chart这都有。
• 阿里仓库 (https://kubernetes.oss-cn-hangzhou.aliyuncs.com/charts)
• 官方仓库 (https://hub.kubeapps.com/charts/incubator) 官方chart仓库，国内有点不好使。
  添加存储库：

helm repo add stable(名字) http://mirror.azure.cn/kubernetes/charts
helm repo add aliyun https://kubernetes.oss-cn-hangzhou.aliyuncs.com/charts
helm repo update

查看配置的存储库：

helm repo list
helm search repo stable

删除存储库：

helm repo remove aliyun

4、Helm基本使用

helm create %name%

$ helm create hellolworld
Creating hellworld

$ tree helloworld
hellworld
|-- Chart.yaml
|-- charts
|-- templates
|   |-- NOTES.txt
|   |-- _helpers.tpl
|   |-- deployment.yaml
|   |-- hpa.yaml
|   |-- ingress.yaml
|   |-- service.yaml
|   |-- serviceaccount.yaml
|   |-- tests
|       |-- test-connection.yaml
|-- values.yaml

Chart.yaml

这个文件中包含的是Chart的元数据

apiVersion: v2
name: demo
description: A Helm chart for Kubernetes

# A chart can be either an 'application' or a 'library' chart.
#
# Application charts are a collection of templates that can be packaged into versioned archives
# to be deployed.
#
# Library charts provide useful utilities or functions for the chart developer. They're included as
# a dependency of application charts to inject those utilities and functions into the rendering
# pipeline. Library charts do not define any templates and therefore cannot be deployed.
type: application

# This is the chart version. This version number should be incremented each time you make changes
# to the chart and its templates, including the app version.
# Versions are expected to follow Semantic Versioning (https://semver.org/)
version: 0.1.0

# This is the version number of the application being deployed. This version number should be
# incremented each time you make changes to the application. Versions are not expected to
# follow Semantic Versioning. They should reflect the version the application is using.
# It is recommended to use it with quotes.
appVersion: "1.16.0"

values.yaml

这个文件中包含Chart的所有可用的配置项，及其默认值。在安装Chart时传递的配置项会覆写这些默认值。

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

replicaCount: 1

image:
  repository: nginx
  pullPolicy: IfNotPresent
  # Overrides the image tag whose default is the chart appVersion.
  tag: ""

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

serviceAccount:
  # Specifies whether a service account should be created
  create: true
  # 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: ClusterIP
  port: 80

ingress:
  enabled: false
  className: ""
  annotations: {}
    # kubernetes.io/ingress.class: nginx
    # kubernetes.io/tls-acme: "true"
  hosts:
    - host: chart-example.local
      paths:
        - path: /
          pathType: ImplementationSpecific
  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: {}

charts目录

包含子chart的目录，这里没用到

templates目录

这个目录包含的是Kubernetes资源声明的模板文件，在安装时，Helm会把模板文件和配置项的值结合起来，得到Kuberbetes资源定义，并应用到Kuberbetes上。

操作演示

示例代码只要保留Deployment、Service和Service Account即可。

 

1. 修改deployment.yaml

containers -> containerPort: 80->8080

2. 修改健康监测节点的探针为 /hello

livenessProbe -> httpGet -> path: /hellp 
readinessProbe -> httpGet -> path: /hello

3. 添加环境变量来传递给微服务

app: -> prefix: "Hello"

4. 设置微服务容器镜像的名称和标签
   镜像的名称在values.yaml中设置，而标签则默认是在Chart.yaml中指定的应用版本号。在实际使用中，一般通过image.tag配置项来传递标签。

replicaCount: 1

image:
  repository: nginx # local/helloworld
  pullPolicy: IfNotPresent
  # Overrides the image tag whose default is the chart appVersion.
  tag: ""

5. 完成Chart的创建之后，就可以使用Helm来安装

helm install myhelloworld .

6. 安装完成之后，还可以使用Helm来更新

helm upgrade --set app.prefix="Greetings" myhellwold .

7. 模板函数另行了解
   https://helm.sh/docs/chart_template_guide/function_list/