Kubernetes 中使用 Helm 部署应用
September 8, 2019 · 649 words · 4 min
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
