第一章 k8s入門（簡單的Java web專案）

環境： VMware Workstation在本機虛擬一個64位的Centos7虛擬機器

• 環境準備

  1. 關閉防火牆

     systemctl disable firewalld
     systemctl stop firewalld
     

  2. 安裝etcd和Kubernetes軟體（會自動安裝Docker軟體）

     yum install -y etcd kubernetes
     

  3. 按順序啟動所有服務

     systemctl start etcd
     systemctl start docker
     systemctl start kube-apiserver
     systemctl start kube-controller-manager
     systemctl start kube-scheduler
     systemctl start kubelet
     systemctl start kube-proxy
      
     

• 啟動MySQL服務

  1. MySQL映象

     docker pull daocloud.io/library/mysql:latest
     

  2. 構建Mysql RC定義檔案(可以使用vim建立)，命名mysql-rc.yaml 內容如下：

     apiVersion: v1
     kind: ReplicationController
     metadata:
       name: mysql
     	spec:
     	  replicas: 1
     	  selector:
     		app: mysql
     	  template:
     		metadata:
     		  labels:
     			app: mysql
     		spec:
     		  containers:
     		  - name: mysql
     			image: mysql
     			ports:
     			- containerPort: 3306
     			env:
     			- name: MYSQL_ROOT_PASSWORD
     			  value: "123456"
      
     

  3. 釋出到kubernetes叢集中，在master節點執行命令（注：此時可能出現問題，如：問題1：no resource found，問題2：status的狀態是ContainerCreating而不是running，如果出現此問題請看關於建立rc和pod出現的問問題）

     $ kubectl create -f mysql-rc.yaml 
     replicationcontroller "mysql" created
     

     檢視建立的rc

     $ kubectl get rc 
     NAME DESIRED CURRENT READY AGE 
     mysql 1 1 1 14s
     

     檢視pod建立情況

     $ kubectl get pods 
     NAME READY STATUS RESTARTS AGE 
     mysql-srd1m 1/1 Running 0 41s
     

  4. 建立一個與之關聯的k8s Service-Mysql的定義檔案（檔名為mysql-svc.yaml）,內容如下：

     apiVersion: v1
     kind: Service
     metadata:
     name: mysql
     spec:
     ports:
     - port: 3306
     selector:
     app: mysql
     

     執行kubectl命令，建立service

     kubectl create -f mysql-svc.yaml
     

     檢視剛剛建立的service

     $ kubectl get svc
     NAME         CLUSTER-IP     EXTERNAL-IP   PORT(S)    AGE
     kubernetes   10.254.0.1     <none>        443/TCP    8d
     mysql        10.254.55.41   <none>        3306/TCP   13s
     

• 啟動Tomcat服務

  1. 拉取Tomcat映象

     	docker pull kubeguide/tomcat-app:v2
     

  2. 構建Tomcat RC定義檔案，命名myweb-rc.yaml 內容如下：

     		apiVersion: v1
     		kind: ReplicationController
     		metadata:
     		  name: myweb
     		spec:
     		  replicas: 2
     		  selector:
     			app: myweb
     		  template:
     			metadata:
     			  labels:
     				app: myweb
     			spec:
     			  containers:
     				- name: myweb
     				  image: kubeguide/tomcat-app:v1
     				  ports:
     				  - containerPort: 8080
     

     完成rc建立和驗證

     	$ kubectl create -f myweb-rc.yaml 
     	replicationcontroller "myweb" created
     	$ kubectl get rc 
     	NAME      DESIRED   CURRENT   READY     AGE
     	mysql     1         1         1         23h
     	myweb     2         2         2         12s
     	$ kubectl get pods
     	NAME          READY     STATUS    RESTARTS   AGE
     	mysql-srd1m   1/1       Running   1          23h
     	myweb-fqlvz   1/1       Running   0          40s
     	myweb-ggrlg   1/1       Running   0          40s
     

  3. 建立對應的Service，檔名（myweb-svc.yaml）,內容如下

     	apiVersion: v1
     	kind: Service
     	metadata: 
     	name: myweb
     	spec:
     	type: NodePort
     	ports:
     	- port: 8080
     	nodePort: 30001
     	selector:
     	app: myweb
     

     建立並驗證

     	$ kubectl create -f myweb-svc.yaml 
     	service "myweb" created
     	$ kubectl get services
     	NAME         CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE
     	kubernetes   10.254.0.1       <none>        443/TCP          8d
     	mysql        10.254.55.41     <none>        3306/TCP         42m
     	myweb        10.254.237.187   <nodes>       8080:30001/TCP   21s