Kubernetes 中使用 Helm 部署应用

清疚 2024-04-18 15:11 87阅读 0赞

# Kubernetes 中使用 Helm 部署应用 #

## 创建应用 ##

创建一个简单的应用，提供一个 REST 接口；使用 Golang 编写，然后将镜像 push 到 Docker Hub

*  go.mod

module github.com/helloworlde/rest
    
    go 1.12

*  main.go

package main
    
    import (
    	"fmt"
    	"log"
    	"net/http"
    )
    
    func main() { 
    	http.HandleFunc("/ping", func(writer http.ResponseWriter, request *http.Request) { 
    		fmt.Println("Pong")
    		_, _ = fmt.Fprint(writer, "Pong")
    	})
    
    	fmt.Println("Server Started")
    	log.Fatal(http.ListenAndServe(":8080", nil))
    }

*  Dockerfile

FROM golang AS build-env
    WORKDIR /go/src/github.com/hellowrolde/rest
    COPY . .
    
    ENV GO111MODULE on
    ENV GOPROXY=https://gocenter.io
    ENV GOOS linux
    ENV GOARCH 386
    
    RUN go mod download
    RUN go build -v -o /go/src/github.com/hellowrolde/rest/app
    
    FROM alpine
    COPY --from=build-env  /go/src/github.com/hellowrolde/rest/app /usr/local/bin/app
    RUN ln -sf /usr/share/zoneinfo/Asia/Shanghai  /etc/localtime
    EXPOSE 8080
    CMD ["app"]

*  构建并 push 镜像

docker build -t hellowooeds/rest . 
    docker push hellowooeds/rest

## 使用 Helm ##

### 添加 Helm ###

#### 初始化 ####

helm create rest

然后会在项目目录下创建一个 rest 的文件夹，里面包含所需要的 Helm 配置文件

.
    ├── Chart.yaml
    ├── charts
    ├── templates
    │   ├── NOTES.txt
    │   ├── _helpers.tpl
    │   ├── deployment.yaml
    │   ├── ingress.yaml
    │   ├── service.yaml
    │   └── tests
    │       └── test-connection.yaml
    └── values.yaml
    
    3 directories, 8 files

*  Chart.yaml: 用于描述 Chart 的属性
 *  values.yaml: 存放项目的配置项，如镜像名称或者 tag 等，用于和模板组装
 *  charts: 用于存放依赖的 chart 的，当有依赖需要管理时，可以添加 requirements.yaml 文件，可用于管理项目内或者外部的依赖
 *  templates: 用于存放需要的配置模板

#### 修改配置文件 ####

*  Chart.yaml

apiVersion: v1
    appVersion: "1.0"
    description: Rest application with Helm
    name: rest
    version: 0.1.0
    maintainers:
      - name: HelloWood

*  修改 values.yaml

backend:
      image: hellowoodes/rest
      tag: "latest"
      pullPolicy: IfNotPresent
      replicas: 1
    
    namespace: rest
    
    service:
      type: NodePort

*  backend-service.yaml

apiVersion: v1
    kind: Service
    metadata:
      labels:
        app: backend
      name: backend
      namespace: { {  .Values.namespace }}
    spec:
      ports:
        - protocol: TCP
          port: 8080
          targetPort: 8080
      selector:
        app: backend
      type: { {  .Values.service.type }}

*  backend-deployment.yaml

apiVersion: extensions/v1beta1
    kind: Deployment
    metadata:
      labels:
        app: backend
      name: backend
      namespace: { {  .Values.namespace }}
    spec:
      selector:
        matchLabels:
          app: backend
      replicas: 1
      template:
        metadata:
          labels:
            app: backend
        spec:
          containers:
            - name: backend
              image: { {  .Values.backend.image }}:{ {  .Values.backend.tag }}
              imagePullPolicy: IfNotPresent
              ports:
                - containerPort: 8080

### 安装应用 ###

helm install ./rest --name rest

如果不指定名称，会随机生成一个

NAME:   rest
    LAST DEPLOYED: Sun Jul 14 18:50:16 2019
    NAMESPACE: default
    STATUS: DEPLOYED
    
    RESOURCES:
    ==> v1/Pod(related)
    NAME                      READY  STATUS             RESTARTS  AGE
    backend-5bc9d6cb99-pfwn5  0/1    ContainerCreating  0         0s
    
    ==> v1/Service
    NAME     TYPE      CLUSTER-IP     EXTERNAL-IP  PORT(S)         AGE
    backend  NodePort  10.105.41.183  <none>       8080:31381/TCP  0s
    
    ==> v1beta1/Deployment
    NAME     READY  UP-TO-DATE  AVAILABLE  AGE
    backend  0/1    1           0          0s
    
    
    NOTES:
    1. Get the application URL by running these commands:
      export NODE_PORT=$(kubectl get service -l app=backend --namespace default -o jsonpath="{.items[0].spec.ports[0].nodePort}")
      export NODE_IP=$(kubectl get nodes --namespace default -o jsonpath="{.items[0].status.addresses[0].address}")
      echo http://$NODE_IP:$NODE_PORT

#### 查看 ####

*  查看 Helm 信息

helm list

NAME	REVISION	UPDATED                 	STATUS  	CHART     	APP VERSION	NAMESPACE
    rest	1       	Sun Jul 14 18:55:25 2019	DEPLOYED	rest-0.1.0	1.0        	default

*  查看 Deployment、Service、Pod

kubectl get all -l app=backend

NAME                           READY   STATUS    RESTARTS   AGE
    pod/backend-5bc9d6cb99-kmpvx   1/1     Running   0          7m15s
    
    NAME                 TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
    service/backend      NodePort    10.104.248.37   <none>        8080:31064/TCP   7m15s
    
    NAME                      READY   UP-TO-DATE   AVAILABLE   AGE
    deployment.apps/backend   1/1     1            1           7m15s
    
    NAME                                 DESIRED   CURRENT   READY   AGE
    replicaset.apps/backend-5bc9d6cb99   1         1         1       7m15s

#### 测试 ####

访问通过 NOTES 获取到的 IP 和端口

http get http://192.168.0.110:31381/ping
    HTTP/1.1 200 OK
    Content-Length: 4
    Content-Type: text/plain; charset=utf-8
    Date: Sun, 14 Jul 2019 10:53:18 GMT
    
    Pong

### 打包 ###

helm package ./rest

Successfully packaged chart and saved it to: /path/to/project/rest-0.1.0.tgz

### 更新 ###

当应用发生了更新之后，需要升级部署，这时候可以通过修改 Helm 的配置来实现；如镜像版本从1.0 更新到 1.1

*  修改 values.yaml

backend:
      image: hellowoodes/rest
      tag: "1.1"
      pullPolicy: IfNotPresent
      replicas: 1
    
    namespace: default
    
    service:
      type: NodePort

*  执行更新

helm upgrade rest ./rest --repo local

Release "rest" has been upgraded. Happy Helming!
    LAST DEPLOYED: Sun Jul 14 21:03:57 2019
    NAMESPACE: default
    STATUS: DEPLOYED
    
    RESOURCES:
    ==> v1/Pod(related)
    NAME                     READY  STATUS   RESTARTS  AGE
    backend-56876f876-vvbzz  1/1    Running  0         85s
    
    ==> v1/Service
    NAME     TYPE      CLUSTER-IP   EXTERNAL-IP  PORT(S)         AGE
    backend  NodePort  10.97.22.28  <none>       8080:31496/TCP  7m10s
    
    ==> v1beta1/Deployment
    NAME     READY  UP-TO-DATE  AVAILABLE  AGE
    backend  1/1    1           1          7m10s
    
    
    NOTES:
    1. Get the application URL by running these commands:
      export NODE_PORT=$(kubectl get service -l app=backend --namespace default -o jsonpath="{.items[0].spec.ports[0].nodePort}")
      export NODE_IP=$(kubectl get nodes --namespace default -o jsonpath="{.items[0].status.addresses[0].address}")
      echo http://$NODE_IP:$NODE_PORT

等待更新完成后，查看 Pod 的描述信息

kubectl describe pod backend-56876f876-vvbzz

可以看到 pod 的镜像已经从 1.0 更新到了 1.1

Normal  Pulled     29s   kubelet, ubuntu-server  Container image "hellowoodes/rest:1.1" already present on machine

###  ###

### 删除应用 ###

删除 Helm 应用后，所有相关的 Service，Deployment，Pod 等都会被删除

helm delete --purge rest

### 查看 Repo 应用 ###

helm serve

Regenerating index. This may take a moment.
    Now serving you on 127.0.0.1:8879

![helm-app-list.png][]

--------------------

### 项目地址 ###

[https://github.com/helloworlde/helm-app-rest][https_github.com_helloworlde_helm-app-rest]

[helm-app-list.png]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly9oZWxsb3dvb2Rlcy5vc3MtY24tYmVpamluZy5hbGl5dW5jcy5jb20vcGljdHVyZS9oZWxtLWFwcC1saXN0LnBuZw?x-oss-process=image/format,png
[https_github.com_helloworlde_helm-app-rest]: https://github.com/helloworlde/helm-app-rest