k8s-----19、Helm

1、引入

• K8S 上的应用对象，都是由特定的资源描述组成，包括 deployment、service 等。都保存 各自文件中或者集中写到一个配置文件。然后 kubectl apply –f 部署。如果应用只由一 个或几个这样的服务组成，上面部署方式足够了。而对于一个复杂的应用，会有很多类似 上面的资源描述文件，例如微服务架构应用，组成应用的服务可能多达十个，几十个。如 果有更新或回滚应用的需求，可能要修改和维护所涉及的大量资源文件，而这种组织和管 理应用的方式就显得力不从心了。且由于缺少对发布过的应用版本管理和控制，使 Kubernetes 上的应用维护和更新等面临诸多的挑战，主要面临以下问题：（1）如何将这 些服务作为一个整体管理 （2）这些资源文件如何高效复用 （3）不支持应用级别的版本管理

2、概述

2.1 重点

• Helm 是一个 Kubernetes 的包管理工具，就像 Linux 下的包管理器，如 yum/apt 等，可以 很方便的将之前打包好的 yaml 文件部署到 kubernetes 上。
• Helm 有 3 个重要概念： （1）helm：一个命令行客户端工具，主要用于 Kubernetes 应用 chart 的创建、打包、发 布和管理。 （2）Chart：简单理解就是把yaml文件进行打包，是yaml文件的集合。官方描述为应用描述，一系列用于描述 k8s 资源相关文件的集合。 （3）Release：基于 Chart 的部署实体。一个 chart 被 Helm 运行后将会生成对应的一个 release；将在 k8s 中创建出真实运行的资源对象。通俗来说，每次部署后都会对应一个版本，也是所说的release。主要是为了进行版本管理。

2.2 V3版本的Helm

2.2.1 与之前版本的不同之处

• 删除了Tiller
• release可以在不同命名空间中进行重用
• 可以将Chart直接推送到docker镜像仓库中

2.2.2 V3版本的运行流程

3、安装和配置仓库、一些附带操作

3.1 安装

官网下载V3版本Helm

 [root@master helm]# tar zxvf helm-v3.8.2-linux-amd64.tar.gz 
linux-amd64/
linux-amd64/helm
linux-amd64/LICENSE
linux-amd64/README.md
[root@master helm]# ls
helm-v3.0.0-linux-amd64.tar.gz  helm-v3.8.2-linux-amd64.tar.gz  linux-amd64
[root@master helm]# cd linux-amd64/
[root@master linux-amd64]# ls
helm  LICENSE  README.md
[root@master linux-amd64]# mv helm /usr/bin/  #移动 

3.2 配置仓库

##添加仓库： helm repo add 自己起仓库名字   仓库地址 
[root@master ~]# helm repo add stable http://mirror.azure.cn/kubernetes/charts  ##添加微软仓库
"stable" has been added to your repositories
[root@master ~]# helm repo add aliyun https://kubernetes.oss-cn-hangzhou.aliyuncs.com/charts 添加阿里云仓库
"aliyun" has been added to your repositories
[root@master ~]# helm repo update  ##更新仓库[root@master ~]# helm repo list  ##列出仓库信息
NAME  	URL                                                   
stable	http://mirror.azure.cn/kubernetes/charts              
aliyun	https://kubernetes.oss-cn-hangzhou.aliyuncs.com/charts[root@master ~]# helm repo remove stable   ##删除仓库
"stable" has been removed from your repositories
[root@master ~]# helm repo list
NAME  	URL                                                   
aliyun	https://kubernetes.oss-cn-hangzhou.aliyuncs.com/charts

3.3 常用命令

命令	描述
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
install	安装一个 chart
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，移除，更新和索引 chart 仓库。可用子命令：add、index、 list、remove、update
rollback	从之前版本回滚
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
uninstall	卸载一个 release
upgrade	更新一个 release
version	查看 helm 客户端版本

3.4 添加helm的自动补齐

[root@master bash_completion.d]# echo "source <(helm completion bash)" >>  ~/.bash_profile
[root@master bash_completion.d]# source ~/.bash_profile [root@master bash_completion.d]# helm completion bash > /usr/share/bash-completion/completions/helm

4、快速部署应用(weave应用)

[root@master ~]# helm install ui aliyun/weave-scope  #出现下面错误是因为仓库的问题，阿里云可能没事实时匹配到k8s，换成微软源可以解决
Error: INSTALLATION FAILED: unable to build kubernetes objects from release manifest: [unable to recognize "": no matches for kind "DaemonSet" in version "extensions/v1beta1", unable to recognize "": no matches for kind "Deployment" in version "apps/v1beta1"][root@master ~]# helm repo add stable http://mirror.azure.cn/kubernetes/charts/   ##添加微软仓库
[root@master ~]# helm repo update
[root@master ~]# helm repo list
NAME  	URL                                                   
aliyun	https://kubernetes.oss-cn-hangzhou.aliyuncs.com/charts
stable	http://mirror.azure.cn/kubernetes/charts/  ##部署           
[root@master ~]# helm search repo weave   ##部署的是一个ui界面应用，所以需要对外暴露端口，需要查看SVC的状态是否为NodePort
NAME              	CHART VERSION	APP VERSION	DESCRIPTION                                       
aliyun/weave-cloud	0.1.2        	           	Weave Cloud is a add-on to Kubernetes which pro...
aliyun/weave-scope	0.9.2        	1.6.5      	A Helm chart for the Weave Scope cluster visual...
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...##helm install 自己起的名称  仓库里包的名称
[root@master ~]# helm install ui stable/weave-scope
WARNING: This chart is deprecated
W0514 11:23:29.545784   20101 warnings.go:70] rbac.authorization.k8s.io/v1beta1 ClusterRole is deprecated in v1.17+, unavailable in v1.22+; use rbac.authorization.k8s.io/v1 ClusterRole
W0514 11:23:29.546481   20101 warnings.go:70] rbac.authorization.k8s.io/v1beta1 ClusterRoleBinding is deprecated in v1.17+, unavailable in v1.22+; use rbac.authorization.k8s.io/v1 ClusterRoleBinding
W0514 11:23:29.567192   20101 warnings.go:70] rbac.authorization.k8s.io/v1beta1 ClusterRole is deprecated in v1.17+, unavailable in v1.22+; use rbac.authorization.k8s.io/v1 ClusterRole
W0514 11:23:29.569900   20101 warnings.go:70] rbac.authorization.k8s.io/v1beta1 ClusterRoleBinding is deprecated in v1.17+, unavailable in v1.22+; use rbac.authorization.k8s.io/v1 ClusterRoleBinding
NAME: ui
LAST DEPLOYED: Sat May 14 11:23:29 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}') 8080:4040then 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/[root@master ~]# helm list   ##查看部署的应用
NAME	NAMESPACE	REVISION	UPDATED                                	STATUS  	CHART             	APP VERSION
ui  	default  	1       	2022-05-14 11:23:29.478377222 +0800 CST	deployed	weave-scope-1.1.12	1.12.0     
[root@master ~]# helm status ui      #查看部署应用的状态
NAME: ui
LAST DEPLOYED: Sat May 14 11:23:29 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/##查看部署情况
[root@master ~]# kubectl get pods   ##查看部署的pod
NAME                                            READY   STATUS    RESTARTS   AGE
weave-scope-agent-ui-d7fv8                      1/1     Running   0          9m21s
weave-scope-agent-ui-mrnb5                      1/1     Running   0          9m21s
weave-scope-agent-ui-nrtrn                      1/1     Running   0          9m21s
weave-scope-cluster-agent-ui-5cbc84db49-fzf7f   1/1     Running   0          9m21s
weave-scope-frontend-ui-6698fd5545-pn8tc        1/1     Running   0          9m21s
web-96d5df5c8-zcshb                             1/1     Running   1          15h
[root@master ~]# kubectl get svc   ##ui-weave-scope的svc状态没有暴露端口
NAME             TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
kubernetes       ClusterIP   10.96.0.1       <none>        443/TCP        65d
ui-weave-scope   ClusterIP   10.101.125.54   <none>        80/TCP         9m25s
web              NodePort    10.96.63.223    <none>        80:31281/TCP   15h      
[root@master ~]# kubectl edit svc ui-weave-scope   ## 编辑内部yaml文件，将状态换为NodePort
service/ui-weave-scope edited
[root@master ~]# kubectl describe svc ui-weave-scope
Name:                     ui-weave-scope
Namespace:                default
Labels:                   app=weave-scopeapp.kubernetes.io/managed-by=Helmchart=weave-scope-frontend-1.1.10component=frontendheritage=Helmrelease=ui
Annotations:              cloud.weave.works/launcher-info:{"server-version": "master-4fe8efe","original-request": {"url": "/k8s/v1.7/scope.yaml"},"email-address": "[e-mail]","source-app": "weave-scope","weave-cloud-component": "scope"}meta.helm.sh/release-name: uimeta.helm.sh/release-namespace: default
Selector:                 app=weave-scope,component=frontend,release=ui
Type:                     NodePort   ##状态已经修改
IP Families:              <none>
IP:                       10.101.125.54
IPs:                      10.101.125.54
Port:                     http  80/TCP
TargetPort:               http/TCP
NodePort:                 http  31055/TCP
Endpoints:                10.244.2.36:4040
Session Affinity:         None
External Traffic Policy:  Cluster
Events:                   <none>
[root@master ~]# kubectl get svc
NAME             TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
kubernetes       ClusterIP   10.96.0.1       <none>        443/TCP        65d
ui-weave-scope   NodePort    10.101.125.54   <none>        80:31055/TCP   15m
web              NodePort    10.96.63.223    <none>        80:31281/TCP   15h

• 最终布置效果
  

5、 自行创建Chart

5.1 Chart目录内容解析

• chart.yaml 指当前chart属性配置信息
• templates 编写的yaml文件放到当前目录
• values.yaml yaml文件可以使用全局变量

5.2 简单安装部署

[root@master ~]# helm create mychart   ##创建Chart[root@master ~]# cd mychart/
[root@master mychart]# ls
charts  Chart.yaml  templates  values.yaml
[root@master mychart]# cd templates/
[root@master templates]# ls
deployment.yaml  hpa.yaml      NOTES.txt            service.yaml  
_helpers.tpl     ingress.yaml  serviceaccount.yaml  tests[root@master mychart]# kubectl create deployment web1 --image=nginx --dry-run -o yaml >
deployment.yaml[root@master mychart]# kubectl create deployment web1 --image=nginx   ##后续创建svc需要web1存在
[root@master templates]# kubectl expose deployment web1 --port=80 --target-port=80 --type=NodePort --dry-run -o yaml > service.yaml   ##创建service.yaml
[root@master ~]# kubectl delete deployments.apps web1    ##删除，一会通过helm进行安装
[root@master templates]# ls
deployment.yaml  service.yaml# helm安装
[root@master ~]# helm install web1 mychart/   ##install+ 自己起名称+ Chart目录
NAME: web1
LAST DEPLOYED: Sat May 14 20:15:51 2022
NAMESPACE: default
STATUS: deployed
REVISION: 1
TEST SUITE: None
[root@master ~]# kubectl get svc
NAME             TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
kubernetes       ClusterIP   10.96.0.1        <none>        443/TCP        66d
ui-weave-scope   NodePort    10.101.125.54    <none>        80:31055/TCP   8h
web              NodePort    10.96.63.223     <none>        80:31281/TCP   24h
web1             NodePort    10.108.249.102   <none>        80:30502/TCP   7s
[root@master ~]# kubectl get pod 
NAME                                            READY   STATUS              RESTARTS   AGE
web1-6fbb48567f-pdgxv                           1/1     Running   0          13s

5.3 应用升级回退

[root@master ~]# helm history web1 
REVISION	UPDATED                 	STATUS    	CHART        	APP VERSION	DESCRIPTION     
1       	Sat May 14 20:15:51 2022	superseded	mychart-0.1.0	1.16.0     	Install complete
2       	Sat May 14 20:18:18 2022	superseded	mychart-0.1.0	1.16.0     	Upgrade complete
3       	Sat May 14 20:18:31 2022	deployed  	mychart-0.1.0	1.16.0     	Rollback to 1   
[root@master ~]# helm upgrade web1 mychart/   ##升级
Release "web1" has been upgraded. Happy Helming!
NAME: web1
LAST DEPLOYED: Sat May 14 20:18:18 2022
NAMESPACE: default
STATUS: deployed
REVISION: 2
TEST SUITE: None
[root@master ~]# helm rollback web1   ##回退到上一版本
Rollback was a success! Happy Helming!
[root@master ~]# helm rollback web1 2  ##回退到指定版本

6、Chart模板实现高效复用

• 通过传递参数，动态渲染模板，yaml文件内容动态传入参数生成。主要是通过value.yaml文件

• 实现主要分为两步：1、通过values.yaml文件定义变量和值；2、在具体的模板下的yaml文件中进行获取变量

• 一般情况下，yaml文件中不同的有name、label、replicas、tag、port

6.1 在values.yaml文件中定义全局变量

[root@master ~]# cd mychart/
[root@master mychart]# ls
charts  Chart.yaml  templates  values.yaml
[root@master mychart]# vim values.yaml 
[root@master mychart]# cat values.yaml    ##主要修改的变量信息
image: nginx
replicas: 1
tag: 1.16
label: nginx
port: 80

6.2 在templates中的yaml文件中定义变量

• 通过表达式形式定义变量 {{ .Values.变量名称}} 还有一种常用的定义名字的{{ .Release.Name}}

[root@master templates]# pwd
/root/mychart/templates[root@master templates]# cat deployment.yaml 
apiVersion: apps/v1
kind: Deployment
metadata:creationTimestamp: nulllabels:app: {{ .Values.label}}name: {{ .Release.Name}}-deploy
spec:replicas: {{ .Values.replicas}}selector:matchLabels:app: {{ .Values.label}}strategy: {}template:metadata:creationTimestamp: nulllabels:app: {{ .Values.label}}spec:containers:- image: {{ .Values.image}}name: {{ .Values.label}}resources: {}
status: {}[root@master templates]# cat service.yaml 
apiVersion: v1
kind: Service
metadata:creationTimestamp: nulllabels:app: {{ .Values.label}}name: {{ .Release.Name}}-svc
spec:ports:- port: {{ .Values.port}}protocol: TCPtargetPort: {{ .Values.port}}selector:app: {{ .Release.Name}}-svctype: NodePort
status:loadBalancer: {}[root@master ~]# helm install web2 mychart/ --dry-run   ##生成说明成功了
NAME: web2
LAST DEPLOYED: Sat May 14 21:33:23 2022
NAMESPACE: default
STATUS: pending-install
REVISION: 1
TEST SUITE: None
HOOKS:
MANIFEST:
---
# Source: mychart/templates/service.yaml
apiVersion: v1
kind: Service
metadata:creationTimestamp: nulllabels:app: nginxname: web2-svc
spec:ports:- port: 80protocol: TCPtargetPort: 80selector:app: web2-svctype: NodePort
status:loadBalancer: {}
---
# Source: mychart/templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:creationTimestamp: nulllabels:app: nginxname: web2-deploy
spec:replicas: 1selector:matchLabels:app: nginxstrategy: {}template:metadata:creationTimestamp: nulllabels:app: nginxspec:containers:- image: nginxname: nginxresources: {}
status: {}
[root@master ~]# helm install web2 mychart/ 
NAME: web2
LAST DEPLOYED: Sat May 14 21:35:06 2022
NAMESPACE: default
STATUS: deployed
REVISION: 1
TEST SUITE: None
[root@master ~]# kubectl get pods
NAME                                            READY   STATUS    RESTARTS   AGE
web2-deploy-6799fc88d8-8khvj                    1/1     Running   0          25s
[root@master ~]# kubectl get svc
NAME             TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
web2-svc         NodePort    10.101.45.10     <none>        80:30704/TCP   30s