15分钟带你体验Kubernetes

前言

最近开始学习Kubernetes，再次记录一些本身学习的一些心得，与你们分享，互相交流，共同进步。node

纯小白一个，欢迎你们批评指正，欢迎评论，谢谢 ~~~git

准备

Ubuntu 18.04 Server LTS （或者 Centos）
暂时不支持Ubuntu 20.04 Server LTS
Firefox浏览器

Kubeasz

github.com/easzlab/kub…github

致力于提供快速部署高可用k8s集群的工具, 同时也努力成为k8s实践、使用的参考书。golang

相比于minikube在国内网络环境下更加友好。web

能够很是便捷的部署一套用于自学的k8s环境。docker

开始

如下内容为Kubeasz AllinOne 文档 AllinOne部署ubuntu

1. 下载文件

下载工具脚本

export release=2.2.1
curl -C- -fLO --retry 3 https://github.com/easzlab/kubeasz/releases/download/${release}/easzup
chmod +x ./easzup
复制代码

使用工具脚本安装k8s以及docker

./easzup -D -d 19.03.5 -k v1.18.2
复制代码

下载离线系统包

./easzup -P
复制代码

上述脚本执行成功之后，全部所需文件均放入目录 /etc/ansible中api

2. 安装集群

容器化启动kubeasz

./easzup -S
复制代码

使用默认配置容许 AllinOne 集群

docker exec -it kubeasz easzctl start-aio
复制代码

3. 验证安装

这里若是提示kubectl: command not found，你能够退出机器从新ssh，或者切换到root权限便可。浏览器

$ kubectl version         # 验证集群版本 
$ kubectl get node        # 验证节点就绪 (Ready) 状态
$ kubectl get pod -A      # 验证集群pod状态，默认已安装网络插件、coredns、metrics-server等
$ kubectl get svc -A      # 验证集群服务状态
复制代码

4. Dashboard

$ kubectl get svc -A

NAMESPACE     NAME                        TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)                  AGE
default       kubernetes                  ClusterIP   10.68.0.1       <none>        443/TCP                  8h
kube-system   dashboard-metrics-scraper   ClusterIP   10.68.117.166   <none>        8000/TCP                 15m
kube-system   kube-dns                    ClusterIP   10.68.0.2       <none>        53/UDP,53/TCP,9153/TCP   8h
kube-system   kubernetes-dashboard        NodePort    10.68.98.36     <none>        443:30001/TCP            15m
kube-system   metrics-server              ClusterIP   10.68.176.123   <none>        443/TCP                  8h
复制代码

能够看到Dashboard 暴露在30001端口下bash

使用Firefox浏览器访问对应IP的30001端口 https://xx.xx.xx.xx:30001

注：这里为啥不用Chrome或者其余嘞？

由于Dashboard的证书缘由，Chrome会显示不是私密链接，而且彻底没有办法进入Dashboard，而Firefox就能够跳过。

使用Token登陆Dashboard

# 建立Service Account 和 ClusterRoleBinding
$ kubectl apply -f /etc/ansible/manifests/dashboard/admin-user-sa-rbac.yaml
# 获取 Bearer Token，找到输出中 ‘token:’ 开头那一行
$ kubectl -n kube-system describe secret $(kubectl -n kube-system get secret | grep admin-user | awk '{print $1}')
复制代码

k8s部署Go语言服务

下面使用kubeasz提供的实例，使用k8s部署Go应用

1. hello.go (github.com/easzlab/kub…)

package main

import (
	"fmt"
	"log"
	"math/rand"
	"net/http"
	"time"
)

var appVersion = "1.2" //Default/fallback version
var instanceNum int

func getFrontpage(w http.ResponseWriter, r *http.Request) {
	t := time.Now()
	fmt.Fprintf(w, "Hello, Go! I'm instance %d running version %s at %s\n", instanceNum, appVersion, t.Format("2019-01-02 15:04:05"))
}

func health(w http.ResponseWriter, r *http.Request) {
	w.WriteHeader(http.StatusOK)
}

func getVersion(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "%s\n", appVersion)
}

func main() {
	rand.Seed(time.Now().UTC().UnixNano())
	instanceNum = rand.Intn(1000)
	http.HandleFunc("/", getFrontpage)
	http.HandleFunc("/health", health)
	http.HandleFunc("/version", getVersion)
	log.Fatal(http.ListenAndServe(":3000", nil))
}
复制代码

2. Dockerfile

FROM golang:latest as builder

COPY *.go /app/

RUN cd /app && go build -o hellogo .

# stage 2: use alpine as base image
FROM golang:latest

COPY --from=builder /app/hellogo /hellogo

CMD ["/hellogo"]
复制代码

3. 容器化hellogo.go

# 构建容器
docker build -t hellogo:v1.0 .
# 容器化运行hellogo服务
docker run -d --name hello -p3000:3000 hellogo:v1.0
# 测试
curl localhost:3000
Hello, Go! I'm instance 814 running version 1.2 at 21069-06-21 14:22:52 复制代码

到此咱们已经容器化了咱们的Go Web程序，接下来使用k8s部署。

4. hellogo.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
 name: hellogo-deploy
spec:
 replicas: 3
 minReadySeconds: 5 # Wait 5 seconds after each new pod comes up before marked as "ready"
 strategy:
 type: RollingUpdate # describe how we do rolling updates
 rollingUpdate:
 maxUnavailable: 1 # When updating take one pod down at a time
 maxSurge: 1
 selector:
 matchLabels:
 name: hellogo-app
 template:
 metadata:
 labels:
 name: hellogo-app
 spec:
 containers:
 - name: hellogo
 image: hellogo:v1.0
 imagePullPolicy: IfNotPresent
 resources:
 requests:
 memory: "32Mi"
 cpu: "50m"
 limits:
 memory: "64Mi"
 cpu: "100m"
 ports:
 - containerPort: 3000

---
apiVersion: v1
kind: Service
metadata:
 name: hellogo-svc
spec:
 type: NodePort
 ports:
 - name: http
 port: 80
 targetPort: 3000
 nodePort: 30002
 selector:
 name: hellogo-app
复制代码

5. k8s部署

部署3个节点的hellogo服务

# 部署
$ kubectl apply -f hellogo.yaml

# 验证
$ kubectl get pod

NAME                              READY   STATUS    RESTARTS   AGE
hellogo-deploy-646655bbf5-6nzdn   1/1     Running   8          17m
hellogo-deploy-646655bbf5-cjbvx   1/1     Running   8          17m
hellogo-deploy-646655bbf5-pkbxq   1/1     Running   8          17m

$kubectl get deploy
NAME             READY   UP-TO-DATE   AVAILABLE   AGE
hellogo-deploy   3/3     3            3           20m

$kubectl get svc
NAME          TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)        AGE
hellogo-svc   NodePort    10.68.199.96   <none>        80:30002/TCP   21m

复制代码

验证

root@ubuntu:/home/chen/hellogo# curl http://172.16.220.129:30002
Hello, Go! I'm instance 449 running version 1.2 at 21069-06-21 14:32:01 root@ubuntu:/home/chen/hellogo# curl http://172.16.220.129:30002 Hello, Go! I'm instance 867 running version 1.2 at 21069-06-21 14:32:02
root@ubuntu:/home/chen/hellogo# curl http://172.16.220.129:30002
Hello, Go! I'm instance 409 running version 1.2 at 21069-06-21 14:32:03 复制代码

有3个不一样id的服务返回了请求，说明部署正常。

结语

此次经过Kubeasz，咱们简单的了解了k8s的基础操做，简单的体验了一下k8s的基本操做，随着学习的不断深刻，将来我还会给你们分享一些本身学习k8s的经验与体会。

谢谢~~~