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Kubernetes入門篇(六)之創建K8S應用

target extension virt host bsp node ash ava -type

  • 一、創建K8S的第一個應用

[root@linux-node1 ~]# kubectl run net-test --image=alpine --replicas=2 sleep 36000  #創建名稱為net-test的應用,鏡像指定為alpine,副本數為2個
deployment.apps "net-test" created
[root@linux-node1 ~]# kubectl get pod -o wide  #查看pod的狀態信息
NAME                        READY     STATUS              RESTARTS   AGE       IP          NODE
net
-test-7b949fc785-2v2qz 1/1 Running 0 56s 10.2.87.2 192.168.56.120 net-test-7b949fc785-6nrhm 0/1 ContainerCreating 0 56s <none> 192.168.56.130 [root@linux-node1 ~]# ping -c 3 10.2.87.2  #檢測pod的連通性 PING 10.2.87.2 (10.2.87.2) 56(84) bytes of data.
64 bytes from 10.2.87.2: icmp_seq=1 ttl=63 time=0.841 ms 64 bytes from 10.2.87.2: icmp_seq=2 ttl=63 time=0.346 ms 64 bytes from 10.2.87.2: icmp_seq=3 ttl=63 time=0.617 ms --- 10.2.87.2 ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 2000ms rtt min/avg/max/mdev = 0.346/0.601/0.841/0.203 ms
  • 二、創建Nginx服務

  • 1、創建deployment
[root@linux-node1 ~]# vim nginx-deployment.yaml  #使用yaml的方式進行創建應用
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.13.12
        ports:
        - containerPort: 80

[root@linux-node1 ~]# kubectl create -f nginx-deployment.yaml #創建nginx-deployment應用
deployment.apps "nginx-deployment" created
  • 2、查看deployment
[root@linux-node1 ~]# kubectl get deployment
NAME               DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
net-test           2         2         2            2           32m
nginx-deployment   3         3         3            0           10s
   
[root@linux-node1 ~]# kubectl describe deployment nginx-deployment    #查看deployment詳情
Name:                   nginx-deployment
Namespace:              default
CreationTimestamp:      Thu, 16 Aug 2018 16:13:37 +0800
Labels:                 app=nginx
Annotations:            deployment.kubernetes.io/revision=1
Selector:               app=nginx
Replicas:               3 desired | 3 updated | 3 total | 0 available | 3 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  25% max unavailable, 25% max surge
Pod Template:
  Labels:  app=nginx
  Containers:
   nginx:
    Image:        nginx:1.13.12
    Port:         80/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Available      False   MinimumReplicasUnavailable
  Progressing    True    ReplicaSetUpdated
OldReplicaSets:  <none>
NewReplicaSet:   nginx-deployment-6c45fc49cb (3/3 replicas created)
Events:
  Type    Reason             Age   From                   Message
  ----    ------             ----  ----                   -------
  Normal  ScalingReplicaSet  1m    deployment-controller  Scaled up replica set nginx-deployment-6c45fc49cb to 3
  • 3、查看Pod
[root@linux-node1 ~]# kubectl get pod    #查看pod在狀態,正在創建中,此時應該正在拉取鏡像
NAME                                READY     STATUS              RESTARTS   AGE
net-test-5767cb94df-djt98           1/1       Running             0          22m
net-test-5767cb94df-hcwv7           1/1       Unknown             0          34m
net-test-5767cb94df-zb8m4           1/1       Running             0          34m
nginx-deployment-6c45fc49cb-dmc22   0/1       ContainerCreating   0          2m
nginx-deployment-6c45fc49cb-fd8xm   0/1       ContainerCreating   0          2m
nginx-deployment-6c45fc49cb-sc8sh   0/1       ContainerCreating   0          2m
   
[root@linux-node1 ~]# kubectl describe pod nginx-deployment-6c45fc49cb-dmc22  #查看具體某個pod的狀態信息
   
[root@linux-node1 ~]# kubectl get pod -o wide  #創建成功,狀態為Running
NAME                                READY     STATUS    RESTARTS   AGE       IP          NODE
net-test-5767cb94df-djt98           1/1       Running   0          24m       10.2.73.3   192.168.56.13
net-test-5767cb94df-hcwv7           1/1       Unknown   0          36m       10.2.10.2   192.168.56.12
net-test-5767cb94df-zb8m4           1/1       Running   0          36m       10.2.73.2   192.168.56.13
nginx-deployment-6c45fc49cb-dmc22   1/1       Running   0          4m        10.2.73.6   192.168.56.13
nginx-deployment-6c45fc49cb-fd8xm   1/1       Running   0          4m        10.2.73.4   192.168.56.13
nginx-deployment-6c45fc49cb-sc8sh   1/1       Running   0          4m        10.2.73.5   192.168.56.13
  • 4、測試Pod訪問
[root@linux-node1 ~]# curl --head http://10.2.73.6
HTTP/1.1 200 OK
Server: nginx/1.13.12
Date: Thu, 16 Aug 2018 08:18:14 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Mon, 09 Apr 2018 16:01:09 GMT
Connection: keep-alive
ETag: "5acb8e45-264"
Accept-Ranges: bytes
  • 5、更新Deployment
[root@linux-node1 ~]# kubectl set image deployment/nginx-deployment nginx=nginx:1.15.2 --record    #nginx的版本升級,由1.13.2升級為1.15.2,記錄需要加參數--record
deployment.apps "nginx-deployment" image updated
   
[root@linux-node1 ~]# kubectl get deployment -o wide  #查看更新後的deployment,可以看到當前4個副本,說明還在滾動升級中
NAME               DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE       CONTAINERS   IMAGES         SELECTOR
net-test           2         2         2            2           39m       net-test     alpine         run=net-test
nginx-deployment   3         4         1            3           6m        nginx        nginx:1.15.2   app=nginx
  • 6、查看更新歷史
[root@linux-node1 ~]# kubectl rollout history deployment/nginx-deployment #查看更新歷史記錄
deployments "nginx-deployment"
REVISION  CHANGE-CAUSE
1         <none>
2         kubectl set image deployment/nginx-deployment nginx=nginx:1.15.2 --record=true
  • 7、查看具體某一個版本的升級歷史
[root@linux-node1 ~]# kubectl rollout history deployment/nginx-deployment --revision=1
deployments "nginx-deployment" with revision #1
Pod Template:
  Labels:    app=nginx
    pod-template-hash=2701970576
  Containers:
   nginx:
    Image:    nginx:1.13.12
    Port:    80/TCP
    Host Port:    0/TCP
    Environment:    <none>
    Mounts:    <none>
  Volumes:    <none>
  • 8、查看更新後的Deployment,並進行訪問
[root@linux-node1 ~]# kubectl get pod -o wide
NAME                                READY     STATUS    RESTARTS   AGE       IP          NODE
net-test-5767cb94df-djt98           1/1       Running   0          30m       10.2.73.3   192.168.56.13
net-test-5767cb94df-hcwv7           1/1       Unknown   0          42m       10.2.10.2   192.168.56.12
net-test-5767cb94df-zb8m4           1/1       Running   0          42m       10.2.73.2   192.168.56.13
nginx-deployment-64749d4b59-djttr   1/1       Running   0          37s       10.2.73.8   192.168.56.13
nginx-deployment-64749d4b59-jp7fw   1/1       Running   0          3m        10.2.73.7   192.168.56.13
nginx-deployment-64749d4b59-q4fsn   1/1       Running   0          33s       10.2.73.9   192.168.56.13
[root@linux-node1 ~]# curl --head http://10.2.73.7
HTTP/1.1 200 OK
Server: nginx/1.15.2  #版本已經升級為1.15.2
Date: Thu, 16 Aug 2018 08:24:09 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 24 Jul 2018 13:02:29 GMT
Connection: keep-alive
ETag: "5b572365-264"
Accept-Ranges: bytes
  • 9、快速回滾到上一個版本
[root@linux-node1 ~]# kubectl rollout undo deployment/nginx-deployment   #回滾上一個版本
deployment.apps "nginx-deployment"    
   
[root@linux-node1 ~]# kubectl get pod -o wide
NAME                                READY     STATUS    RESTARTS   AGE       IP           NODE
net-test-5767cb94df-djt98           1/1       Running   0          32m       10.2.73.3    192.168.56.13
net-test-5767cb94df-hcwv7           1/1       Unknown   0          43m       10.2.10.2    192.168.56.12
net-test-5767cb94df-zb8m4           1/1       Running   0          43m       10.2.73.2    192.168.56.13
nginx-deployment-6c45fc49cb-b9h84   1/1       Running   0          24s       10.2.73.11   192.168.56.13
nginx-deployment-6c45fc49cb-g4mrg   1/1       Running   0          26s       10.2.73.10   192.168.56.13
nginx-deployment-6c45fc49cb-k29kq   1/1       Running   0          21s       10.2.73.12   192.168.56.13
[root@linux-node1 ~]# curl --head http://10.2.73.10
HTTP/1.1 200 OK
Server: nginx/1.13.12
Date: Thu, 16 Aug 2018 08:25:35 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Mon, 09 Apr 2018 16:01:09 GMT
Connection: keep-alive
ETag: "5acb8e45-264"
Accept-Ranges: bytes

回滾完成,每一次更新或者回滾ip都會變化,所以需要通過vip進行訪問,這就引入了service   
  • 10、使用service的vip進行訪問應用
[root@linux-node1 ~]# vim nginx-service.yaml  #使用yaml方式創建service
kind: Service
apiVersion: v1
metadata:
  name: nginx-service
spec:
  selector:
    app: nginx
  ports:
  - protocol: TCP
    port: 80
    targetPort: 80

[root@linux-node1 ~]# kubectl create -f nginx-service.yaml   #創建service
service "nginx-service" created

[root@linux-node1 ~]# kubectl get service
NAME            TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)   AGE
kubernetes      ClusterIP   10.1.0.1       <none>        443/TCP   4h
nginx-service   ClusterIP   10.1.213.126   <none>        80/TCP    15s  #這個就是vip

[root@linux-node2 ~]# curl --head http://10.1.213.126  #在node2節點上進行訪問vip測試,在node1上無法訪問是因為沒有安裝kube-proxy導致無法訪問
HTTP/1.1 200 OK
Server: nginx/1.13.12
Date: Thu, 16 Aug 2018 08:30:08 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Mon, 09 Apr 2018 16:01:09 GMT
Connection: keep-alive
ETag: "5acb8e45-264"
Accept-Ranges: bytes

[root@linux-node2 ~]# ipvsadm -Ln  
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  10.1.0.1:443 rr persistent 10800
  -> 192.168.56.11:6443           Masq    1      0          0         
TCP  10.1.213.126:80 rr
  -> 10.2.73.10:80                Masq    1      0          1         
  -> 10.2.73.11:80                Masq    1      0          1         
  -> 10.2.73.12:80                Masq    1      0          0   

查看LVS狀態可以看到,當訪問VIP:10.1.213.126時,會進行負載均衡到各個pod
  • 11、擴容到5個節點
[root@linux-node1 ~]# kubectl scale deployment nginx-deployment --replicas 5  #對應用的副本數進行擴容,直接指定副本數為5
deployment.extensions "nginx-deployment" scaled

[root@linux-node1 ~]# kubectl get pod  #查看pod狀態,可以看到已經增加到5個副本
NAME                                READY     STATUS    RESTARTS   AGE
net-test-5767cb94df-djt98           1/1       Running   0          38m
net-test-5767cb94df-hcwv7           1/1       Unknown   0          50m
net-test-5767cb94df-zb8m4           1/1       Running   0          50m
nginx-deployment-6c45fc49cb-b9h84   1/1       Running   0          6m
nginx-deployment-6c45fc49cb-g4mrg   1/1       Running   0          7m
nginx-deployment-6c45fc49cb-k29kq   1/1       Running   0          6m
nginx-deployment-6c45fc49cb-n9qkx   1/1       Running   0          24s
nginx-deployment-6c45fc49cb-xpx9s   1/1       Running   0          24s

[root@linux-node2 ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  10.1.0.1:443 rr persistent 10800
  -> 192.168.56.11:6443           Masq    1      0          0         
TCP  10.1.213.126:80 rr
  -> 10.2.73.10:80                Masq    1      0          0         
  -> 10.2.73.11:80                Masq    1      0          0         
  -> 10.2.73.12:80                Masq    1      0          1         
  -> 10.2.73.13:80                Masq    1      0          0         
  -> 10.2.73.14:80                Masq    1      0          0         

Kubernetes入門篇(六)之創建K8S應用