今天我们继续学习kubernetes内容Helm

一、Helm概述

helm通过打包的方式，支持发布的版本管理和控制，很大程度上简化了Kubernetes应用的部署和管理。

Helm本质就是让k8s的应用管理（Deployment、Service等）可配置，能动态生成。通过动态生成K8S资源清单文（deployment.yaml、service.yaml）。然后kubectl自动调用K8S资源部署。

对于K8s来说，应用资源配置可以定义为K8s API对象，包括Deployment，Namespace，Service， PV（Persistent Volumes）和PVC（PersistentVolumeClaims）等等。通常一个应用的部署会涉及很多资源的共同协作，用户会定义这些API对象到一系列Yaml文件中，然后通过kubectl来逐一进行部署。

Helm 组件及相关术语

Helm是官方提供类似于YUM的包管理，是部署环境的流程封装，Helm有三个重要的概念：chart、release和Repository

• Helm：Helm 是一个命令行下的客户端工具。主要用于 Kubernetes 应用程序 Chart 的创建、打包、发布以及创建和管理本地和远程的 Chart 仓库。

• Tiller：Tiller 是 Helm 的服务端，部署在 Kubernetes 集群中。Tiller 用于接收 Helm 的请求，并根据 Chart 生成 Kubernetes 的部署文件（ Helm 称为 Release ），然后提交给 Kubernetes 创建应用。Tiller 还提供了 Release 的升级、删除、回滚等一系列功能。

• Chart：Helm 的软件包，采用 TAR 格式。类似于 APT 的 DEB 包或者 YUM 的 RPM 包，其包含了一组定义 Kubernetes 资源相关的 YAML 文件。Chart有特定的文件目录结构，如果开发者想自定义一个新的 Chart，只需要使用Helm create命令生成一个目录结构即可进行开发。

• Repoistory：Helm 的软件仓库，Repository 本质上是一个 Web 服务器，该服务器保存了一系列的 Chart 软件包以供用户下载，并且提供了一个该 Repository 的 Chart 包的清单文件以供查询。Helm 可以同时管理多个不同的 Repository， 官方仓库的地址是https://hub.helm.sh。

• Release：使用 helm install 命令在 Kubernetes 集群中部署的 Chart 称为 Release。

二、Helm部署

安装

[root@k8s-master01 ~]# mkdir helm [root@k8s-master01 helm]# wget https://get.helm.sh/helm-v3.14.0-linux-amd64.tar.gz [root@k8s-master01 helm]# tar -zxvf helm-v3.14.0-linux-amd64.tar.gz [root@k8s-master01 helm]# cd linux-amd64/ [root@k8s-master01 linux-amd64]# cp helm /usr/local/bin/ [root@k8s-master01 linux-amd64]# echo "source <(helm completion bash)" >> ~/.bashrc [root@k8s-master01 linux-amd64]# source ~/.bashrc

chart库配置

使用helm search搜索官方helm hub chart库

helm search hub nginx

添加第三方Chart库

helm repo add aliyun https://kubernetes.oss-cn-hangzhou.aliyuncs.com/charts helm repo add bitnami https://charts.bitnami.com/bitnami

查看Chart库

helm repo list

从仓库中查找指定chart的名字

helm search repo nginx

Helm命令

三、Helm Chart 详解

chart目录结构

# 通过helm create命令创建一个新的chart包 [root@k8s-master01 helm]# helm create nginx Creating nginx [root@k8s-master01 nginx]# tree . ├── charts ├── Chart.yaml ├── templates │ ├── deployment.yaml │ ├── _helpers.tpl │ ├── hpa.yaml │ ├── ingress.yaml │ ├── NOTES.txt │ ├── serviceaccount.yaml │ ├── service.yaml │ └── tests │ └── test-connection.yaml └── values.yaml 3 directories, 10 files ####目录结构解析#### nginx/ ├── charts #依赖其他包的charts文件 ├── Chart.yaml # 该chart的描述文件,包括ico地址,版本信息等 ├── templates # #存放k8s模板文件目录 │ ├── deployment.yaml # 创建k8s资源的yaml 模板 │ ├── _helpers.tpl # 下划线开头的文件,可以被其他模板引用 │ ├── hpa.yaml # 弹性扩缩容，配置服务资源CPU 内存 │ ├── ingress.yaml # ingress 配合service域名访问的配置 │ ├── NOTES.txt # 说明文件,helm install之后展示给用户看的内容 │ ├── serviceaccount.yaml # 服务账号配置 │ ├── service.yaml # kubernetes Serivce yaml 模板 │ └── tests # 测试模块 │ └── test-connection.yaml └── values.yaml # 给模板文件使用的变量

部署Nginx应用

[root@k8s-master01 nginx-helm]# helm pull bitnami/nginx --version 15.3.5 [root@k8s-master01 nginx-helm]# ls nginx-15.3.5.tgz [root@k8s-master01 nginx-helm]# tar xf nginx-15.3.5.tgz [root@k8s-master01 nginx-helm]# ls nginx nginx-15.3.5.tgz [root@k8s-master01 nginx-helm]# cd nginx [root@k8s-master01 nginx]# vim values.yaml 532 service: 533 ## @param service.type Service type 534 ## 535 type: ClusterIP 536 ## @param service.ports.http Service HTTP port 537 ## @param service.ports.https Service HTTPS port 538 ## 539 ports: 540 http: 80 541 https: 443 ###安装chart### [root@k8s-master01 nginx]# helm install nginx-server . NAME: nginx-server LAST DEPLOYED: Sat Feb 3 15:57:33 2024 NAMESPACE: default STATUS: deployed REVISION: 1 TEST SUITE: None NOTES: CHART NAME: nginx CHART VERSION: 15.3.5 APP VERSION: 1.25.3 ** Please be patient while the chart is being deployed ** NGINX can be accessed through the following DNS name from within your cluster: nginx-server.default.svc.cluster.local (port 80) To access NGINX from outside the cluster, follow the steps below: 1. Get the NGINX URL by running these commands: export SERVICE_PORT=$(kubectl get --namespace default -o jsonpath="{.spec.ports[0].port}" services nginx-server) kubectl port-forward --namespace default svc/nginx-server ${SERVICE_PORT}:${SERVICE_PORT} & echo "http://127.0.0.1:${SERVICE_PORT}" ####查看pod和service### [root@k8s-master01 nginx]# kubectl get deployments.apps NAME READY UP-TO-DATE AVAILABLE AGE nginx-deploy 3/3 3 3 23h nginx-deploy1 3/3 3 3 22h nginx-deploy2 3/3 3 3 22h nginx-server 1/1 1 1 56s [root@k8s-master01 nginx]# kubectl get pod NAME READY STATUS RESTARTS AGE nginx-deploy-5f87d95c-7ph78 1/1 Running 1 (151m ago) 23h nginx-deploy-5f87d95c-dswvq 1/1 Running 1 (151m ago) 23h nginx-deploy-5f87d95c-vk9vg 1/1 Running 1 (151m ago) 23h nginx-deploy1-c8d58b5c7-7dfrd 1/1 Running 1 (151m ago) 22h nginx-deploy1-c8d58b5c7-d2hd7 1/1 Running 1 (151m ago) 22h nginx-deploy1-c8d58b5c7-pfvhn 1/1 Running 1 (151m ago) 22h nginx-deploy2-db98bd9d9-2jl74 1/1 Running 1 (151m ago) 22h nginx-deploy2-db98bd9d9-h67n6 1/1 Running 1 (151m ago) 22h nginx-deploy2-db98bd9d9-wfcmw 1/1 Running 1 (151m ago) 22h nginx-server-ff5765f8-4wbms 1/1 Running 0 2m5s pod-controller-qk5jl 1/1 Running 1 (151m ago) 19h pod-controller-scsxt 1/1 Running 1 (151m ago) 19h [root@k8s-master01 nginx]# kubectl get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.10.0.1 <none> 443/TCP 14d nginx-server ClusterIP 10.10.127.16 <none> 80/TCP 2m32s nginx-svc ClusterIP 10.10.83.76 <none> 80/TCP 23h nginx-svc1 LoadBalancer 10.10.168.131 192.168.115.167 80:31261/TCP 22h nginx-svc2 NodePort 10.10.14.245 <none> 80:31110/TCP 22h ####测试访问### [root@k8s-master01 nginx]# curl 10.10.127.16 <!DOCTYPE html> <html> <head> <title>Welcome to nginx!</title> <style> html { color-scheme: light dark; } body { width: 35em; margin: 0 auto; font-family: Tahoma, Verdana, Arial, sans-serif; } </style> </head> <body> <h1>Welcome to nginx!</h1> <p>If you see this page, the nginx web server is successfully installed and working. Further configuration is required.</p> <p>For online documentation and support please refer to <a href="http://nginx.org/">nginx.org</a>.<br/> Commercial support is available at <a href="http://nginx.com/">nginx.com</a>.</p> <p><em>Thank you for using nginx.</em></p> </body> </html>

四、升级与回滚

修改配置文件

[root@k8s-master01 nginx]# vim values.yaml 123 replicaCount: 3 124 ## @param revisionHistoryLimit The number of old history to retain to allow rollback 125 ##

升级

[root@k8s-master01 nginx]# helm upgrade nginx-server

查看升级结果

[root@k8s-master01 nginx]# kubectl get pod [root@k8s-master01 nginx]# kubectl get pod NAME READY STATUS RESTARTS AGE nginx-deploy-5f87d95c-7ph78 1/1 Running 1 (166m ago) 23h nginx-deploy-5f87d95c-dswvq 1/1 Running 1 (166m ago) 23h nginx-deploy-5f87d95c-vk9vg 1/1 Running 1 (166m ago) 23h nginx-deploy1-c8d58b5c7-7dfrd 1/1 Running 1 (166m ago) 23h nginx-deploy1-c8d58b5c7-d2hd7 1/1 Running 1 (166m ago) 23h nginx-deploy1-c8d58b5c7-pfvhn 1/1 Running 1 (166m ago) 23h nginx-deploy2-db98bd9d9-2jl74 1/1 Running 1 (166m ago) 22h nginx-deploy2-db98bd9d9-h67n6 1/1 Running 1 (166m ago) 22h nginx-deploy2-db98bd9d9-wfcmw 1/1 Running 1 (166m ago) 22h nginx-server-ff5765f8-4p6sh 1/1 Running 0 31s nginx-server-ff5765f8-4wbms 1/1 Running 0 16m nginx-server-ff5765f8-lnkkg 1/1 Running 0 31s

查看记录

[root@k8s-master01 nginx]# helm history nginx-server REVISION UPDATED STATUS CHART APP VERSION DESCRIPTION 1 Sat Feb 3 15:57:33 2024 superseded nginx-15.3.5 1.25.3 Install complete 2 Sat Feb 3 16:13:44 2024 deployed nginx-15.3.5 1.25.3 Upgrade complete

回滚

[root@k8s-master01 nginx]# helm rollback nginx-server 1

验证回滚

[root@k8s-master01 nginx]# kubectl get pod NAME READY STATUS RESTARTS AGE nginx-deploy-5f87d95c-7ph78 1/1 Running 1 (170m ago) 23h nginx-deploy-5f87d95c-dswvq 1/1 Running 1 (170m ago) 23h nginx-deploy-5f87d95c-vk9vg 1/1 Running 1 (170m ago) 23h nginx-deploy1-c8d58b5c7-7dfrd 1/1 Running 1 (170m ago) 23h nginx-deploy1-c8d58b5c7-d2hd7 1/1 Running 1 (170m ago) 23h nginx-deploy1-c8d58b5c7-pfvhn 1/1 Running 1 (170m ago) 23h nginx-deploy2-db98bd9d9-2jl74 1/1 Running 1 (170m ago) 22h nginx-deploy2-db98bd9d9-h67n6 1/1 Running 1 (170m ago) 22h nginx-deploy2-db98bd9d9-wfcmw 1/1 Running 1 (170m ago) 22h nginx-server-ff5765f8-lnkkg 1/1 Running 0 4m44s

卸载

[root@k8s-master01 nginx]# helm uninstall nginx-server