kubernetes helm

 一、helm介绍

二、helm 3 安装使用

# 下载，安装
wget https://get.helm.sh/helm-v3.4.2-linux-amd64.tar.gz

tar -zxvf helm-v3.4.2-linux-amd64.tar.gz 

mv linux-amd64/helm /usr/bin/helm

添加存储库
helm repo add stable http://mirror.azure.cn/kubernetes/charts
helm repo add aliyun https://kubernetes.oss-cn-hangzhou.aliyuncs.com/charts

更新产库地址
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


helm 基本使用
主要介绍三个命令：
 chart install
 chart upgrade
 chart rollback

使用 chart 部署一个应用
# helm search repo weave
[root@master-node helm]# helm search repo weave
NAME                    CHART VERSION   APP VERSION     DESCRIPTION                                       
stable/weave-cloud      0.3.9           1.4.0           DEPRECATED - Weave Cloud is a add-on to Kuberne...
stable/weave-scope      1.1.12          1.12.0          DEPRECATED - A Helm chart for the Weave Scope c...
[root@master-node helm]# 


#查看 chrt 信息
# helm show chart stable/mysql
[root@master-node helm]# helm show chart stable/mysql
apiVersion: v1
appVersion: 5.7.30
deprecated: true
description: DEPRECATED - Fast, reliable, scalable, and easy to use open-source relational
  database system.
home: https://www.mysql.com/
icon: https://www.mysql.com/common/logos/logo-mysql-170x115.png
keywords:
- mysql
- database
- sql
name: mysql
sources:
- https://github.com/kubernetes/charts
- https://github.com/docker-library/mysql
version: 1.6.9


#安装包
# helm install ui stable/weave-scope

#查看发布状态
# helm list
[root@master-node helm]# helm list
NAME    NAMESPACE       REVISION        UPDATED                                 STATUS          CHART                 APP VERSION
ui      default         1               2022-02-21 17:18:53.936160584 +0800 CST deployed        weave-scope-1.1.12    1.12.0     

#helm status 安装之后名称
[root@master-node helm]# helm status ui
NAME: ui
LAST DEPLOYED: Mon Feb 21 17:18:53 2022
NAMESPACE: default
STATUS: deployed
REVISION: 1
NOTES:
You should now be able to access the Scope frontend in your web browser, by
using kubectl port-forward:

kubectl -n default port-forward $(kubectl -n default get endpoints \
ui-weave-scope -o jsonpath='{.subsets[0].addresses[0].targetRef.name}') 8080:4040

then browsing to http://localhost:8080/.
For more details on using Weave Scope, see the Weave Scope documentation:

https://www.weave.works/docs/scope/latest/introducing/

#删除应用
[root@master-node home]# helm delete ui
release "ui" uninstalled

#kubernetes修改service的yaml文件
#查看所有的服务 
kubectl get service
或
kubectl get svc
#修改服务文件: 
kubectl edit svc [service名字]

三、构建一个helm Chart

#构建一个 Helm Chart
[root@master-node helm]# helm create mychart
Creating mychart

#查看目录结构
[root@master-node helm]# tree mychart/
mychart/
├── charts              # 依赖信息
├── Chart.yaml          # chart版本和配置信息
├── templates            # K8s 资源模板信息, 结合 values.yaml 可生成K8s对象的manifest文件
│   ├── deployment.yaml   
│   ├── _helpers.tpl        # 下划线开头,作为子模板,可被其他模板文件引用,Helm不会交给K8s处理
│   ├── ingress.yaml
│   ├── NOTES.txt          # helm 提示信息
│   ├── serviceaccount.yaml
│   ├── service.yaml          
│   └── tests
│       └── test-connection.yaml
└── values.yaml            # chart默认配置

Chart.yaml：用于描述这个 Chart 的基本信息，包括名字、描述信息以及版本等。
values.yaml ：用于存储 templates 目录中模板文件中用到变量的值。
Templates： 目录里面存放所有 yaml 模板文件。
charts：目录里存放这个 chart 依赖的所有子 chart。
NOTES.txt ：用于介绍 Chart 帮助信息， helm install 部署后展示给用户。例如：如何使用这个 Chart、列出缺省的设置等。
_helpers.tpl：放置模板助手的地方，可以在整个 chart 中重复使用


#创建deploymentyaml文件
# --dry-run参数  ：试着运行，不真正运行。
[root@master-node templates]# kubectl create deployment web1 --image=nginx --dry-run -o yaml > deployment.yml
W0222 10:55:52.334693   20222 helpers.go:553] --dry-run is deprecated and can be replaced with --dry-run=client.
[root@master-node templates]# ll
total 4
-rw-r--r-- 1 root root 380 Feb 22 10:55 deployment.yml

#对外发布，暴露nginx端口号，这里没加--dry-run参数，所以输出yaml文件的时候也同时执行了，
[root@master-node templates]# kubectl expose deployment web --port=80 --type=NodePort --target-port=80 --name=web1 -o yaml > service.yaml
[root@master-node templates]# ll
total 8
-rw-r--r-- 1 root root  380 Feb 22 10:55 deployment.yml
-rw-r--r-- 1 root root 1059 Feb 22 11:04 service.yaml
[root@master-node templates]#

#创建 Chart 后，接下来就是将其部署：
#helm install web mychart/

[root@master-node helm]# helm install web mychart/
NAME: web
LAST DEPLOYED: Tue Feb 22 11:08:59 2022
NAMESPACE: default
STATUS: deployed
REVISION: 1
TEST SUITE: None

#应用升级
helm upgrade chart名称

 四、实现yaml高效复用

vi values.yaml

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

replicas: 1
image: nginx
tag: 1.16
label: nginx
port: 80

image:
  repository: nginx
  pullPolicy: IfNotPresent

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

serviceAccount:
  # Specifies whether a service account should be created
  create: true
  # The name of the service account to use.
  # If not set and create is true, a name is generated using the fullname template
  name:

podSecurityContext: {}
  # fsGroup: 2000

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

[root@master-node mychart]# vi templates/deployment.yml 
apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    app: web1
  name: {{ .Release.Name }}-configmap
spec:
  replicas: 1
  selector:
    matchLabels:
      app: {{.values.label}}
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: {{.values.label}}
    spec:
      containers:
      - image: {{.values.image}}
        name: nginx
        resources: {}
status: {}

[root@master-node mychart]# vi templates/service.yaml 
apiVersion: v1
kind: Service
metadata:
  creationTimestamp: "2022-02-22T03:04:45Z"
  labels:
    app: {{ .Release.Name }}-svc
  managedFields:
  - apiVersion: v1
    fieldsType: FieldsV1
    fieldsV1:
      f:metadata:
        f:labels:
          .: {}
          f:app: {}
      f:spec:
        f:externalTrafficPolicy: {}
        f:ports:
          .: {}
          k:{"port":80,"protocol":"TCP"}:
            .: {}
            f:port: {}
            f:protocol: {}
            f:targetPort: {}
        f:selector:
          .: {}
          f:app: {}
        f:sessionAffinity: {}
        f:type: {}
    manager: kubectl-expose
    operation: Update
    time: "2022-02-22T03:04:45Z"
  name: web1
  namespace: default
  resourceVersion: "7352599"
  selfLink: /api/v1/namespaces/default/services/web1
  uid: 81ebe4da-8e6e-4679-af48-0f4bf95cb6ae
spec:
  clusterIP: 10.96.6.182
  externalTrafficPolicy: Cluster
  ports:
  - nodePort: 31259
    port: {{ .values.port }}
    protocol: TCP
    targetPort: 80
  selector:
    app: {{ .values.label }}
  sessionAffinity: None
  type: NodePort
status:
  loadBalancer: {}