k8s入门基本操作

1、部署一个Tomcat

kubectl create deployment tomcat6 --image=tomcat:6.0.53-jre8


[root@k8s-node1 k8s]# kubectl get all
NAME                           READY   STATUS    RESTARTS   AGE
pod/tomcat6-5f7ccf4cb9-tft59   1/1     Running   0          77m

NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
service/kubernetes   ClusterIP   172.96.0.1   <none>        443/TCP   81m

NAME                      READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/tomcat6   1/1     1            1           77m

NAME                                 DESIRED   CURRENT   READY   AGE
replicaset.apps/tomcat6-5f7ccf4cb9   1         1         1       77m
[root@k8s-node1 k8s]# kubectl get all -o wide  #可以获取到tomcat信息
NAME                           READY   STATUS    RESTARTS   AGE   IP            NODE        NOMINATED NODE   READINESS GATES
pod/tomcat6-5f7ccf4cb9-tft59   1/1     Running   0          79m   172.244.2.2   k8s-node3   <none>           <none>

NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE   SELECTOR
service/kubernetes   ClusterIP   172.96.0.1   <none>        443/TCP   83m   <none>

NAME                      READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS   IMAGES               SELECTOR
deployment.apps/tomcat6   1/1     1            1           79m   tomcat       tomcat:6.0.53-jre8   app=tomcat6

NAME                                 DESIRED   CURRENT   READY   AGE   CONTAINERS   IMAGES               SELECTOR
replicaset.apps/tomcat6-5f7ccf4cb9   1         1         1       79m   tomcat       tomcat:6.0.53-jre8   app=tomcat6,pod-template-hash=5f7ccf4cb9

[root@k8s-node1 k8s]# kubectl get pods
NAME                       READY   STATUS    RESTARTS   AGE
tomcat6-5f7ccf4cb9-tft59   1/1     Running   0          83m
[root@k8s-node1 k8s]# kubectl get pods --all-namespaces
NAMESPACE     NAME                                READY   STATUS    RESTARTS   AGE
default       tomcat6-5f7ccf4cb9-tft59            1/1     Running   0          83m
kube-system   coredns-7f9c544f75-fkxhb            1/1     Running   0          87m
kube-system   coredns-7f9c544f75-j2wfg            1/1     Running   0          87m
kube-system   etcd-k8s-node1                      1/1     Running   0          87m
kube-system   kube-apiserver-k8s-node1            1/1     Running   0          87m
kube-system   kube-controller-manager-k8s-node1   1/1     Running   0          87m
kube-system   kube-flannel-ds-amd64-89kvs         1/1     Running   0          85m
kube-system   kube-flannel-ds-amd64-fh474         1/1     Running   0          86m
kube-system   kube-flannel-ds-amd64-rvscb         1/1     Running   0          87m
kube-system   kube-proxy-h7wfr                    1/1     Running   0          85m
kube-system   kube-proxy-mb4l5                    1/1     Running   0          86m
kube-system   kube-proxy-vsjxb                    1/1     Running   0          87m
kube-system   kube-scheduler-k8s-node1            1/1     Running   0          87m

tomcat在k8s-node3节点

[root@k8s-node3 k8s]# docker images
REPOSITORY                                                       TAG             IMAGE ID       CREATED         SIZE
tomcat                                                           6.0.53-jre8     49ab0583115a   3 years ago     290MB

[root@k8s-node3 k8s]# docker ps
CONTAINER ID   IMAGE                                                            COMMAND                  CREATED             STATUS             PORTS     NAMES
a58c4fc582f6   tomcat                                                           "catalina.sh run"        About an hour ago   Up About an hour             k8s_tomcat_tomcat6-5f7ccf4cb9-tft59_default_dd2d9b08-88f6-494c-b922-161a70c9c38b_0

模拟k8s-node3宕机，会在k8s-node2上启动一个tomcat，容灾恢复
[root@k8s-node1 ~]#  kubectl get pods -o wide

NAME                       READY   STATUS    RESTARTS   AGE   IP            NODE        NOMINATED NODE   READINESS GATES
tomcat6-5f7ccf4cb9-8nfq5   1/1     Running   0          23m   172.244.1.4   k8s-node2   <none>           <none>

2、暴露nginx访问

kubectl expose deployment tomcat6 --port=80 --target-port=8080 --type=NodePort
service/tomcat6 exposed

Pod的80映射容器的8080；service会代理Pod的80

[root@k8s-node1 ~]# kubectl get service
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP   172.96.0.1       <none>        443/TCP        137m
tomcat6      NodePort    172.96.156.221   <none>        80:32759/TCP   22s

[root@k8s-node1 ~]# kubectl get service -o wide
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE    SELECTOR
kubernetes   ClusterIP   172.96.0.1       <none>        443/TCP        139m   <none>
tomcat6      NodePort    172.96.156.221   <none>        80:32759/TCP   98s    app=tomcat6

发现80端口对外暴露了32759端口,浏览器访问http://192.168.54.161:32759/ http://192.168.54.162:32759/ http://192.168.54.163:32759/

均可以访问tomcat主页

3、动态扩容测试

kubectl get deployment

应用升级 kubectl set image (--help 查看帮助)
扩容 kubectl scale --replicas=3 deployment tomcat6
扩容了多份，所有无论访问哪个node的指定端口，都可以访问到tomcat6

#在k8s-node2 节点有两个 k8s-node3节点有一个
[root@k8s-node1 ~]# kubectl get pods -o wide
NAME                       READY   STATUS    RESTARTS   AGE   IP            NODE        NOMINATED NODE   READINESS GATES
tomcat6-5f7ccf4cb9-8nfq5   1/1     Running   0          42m   172.244.1.4   k8s-node2   <none>           <none>
tomcat6-5f7ccf4cb9-t8sd6   1/1     Running   0          27s   172.244.1.5   k8s-node2   <none>           <none>
tomcat6-5f7ccf4cb9-xr56v   1/1     Running   0          27s   172.244.2.5   k8s-node3   <none>           <none>

[root@k8s-node1 ~]# kubectl get service -o wide
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE    SELECTOR
kubernetes   ClusterIP   172.96.0.1       <none>        443/TCP        148m   <none>
tomcat6      NodePort    172.96.156.221   <none>        80:32759/TCP   10m    app=tomcat6

#缩容
kubectl scale --replicas=1 deployment tomcat6
#只有k8s-node3节点有一个
[root@k8s-node1 ~]# kubectl get pods -o wide
NAME                       READY   STATUS    RESTARTS   AGE     IP            NODE        NOMINATED NODE   READINESS GATES
tomcat6-5f7ccf4cb9-xr56v   1/1     Running   0          3m29s   172.244.2.5   k8s-node3   <none>           <none>

删除资源

获取所有资源
[root@k8s-node1 ~]# kubectl get all
NAME                           READY   STATUS    RESTARTS   AGE
pod/tomcat6-5f7ccf4cb9-xr56v   1/1     Running   0          5m59s

NAME                 TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
service/kubernetes   ClusterIP   172.96.0.1       <none>        443/TCP        153m
service/tomcat6      NodePort    172.96.156.221   <none>        80:32759/TCP   15m

NAME                      READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/tomcat6   1/1     1            1           149m

NAME                                 DESIRED   CURRENT   READY   AGE
replicaset.apps/tomcat6-5f7ccf4cb9   1         1         1       149m

删除部署信息
[root@k8s-node1 ~]# kubectl delete deployment.apps/tomcat6 
删除service
[root@k8s-node1 ~]# kubectl delete service/tomcat6

查看命令帮助信息 --help

kubectl create deployment tomcat6 --image=tomcat:6.0.53-jre8 --help

输出部署命令的yaml配置

kubectl create deployment tomcat6 --image=tomcat:6.0.53-jre8 --dry-run -o yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    app: tomcat6
  name: tomcat6
spec:
  replicas: 1
  selector:
    matchLabels:
      app: tomcat6
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: tomcat6
    spec:
      containers:
      - image: tomcat:6.0.53-jre8
        name: tomcat
        resources: {}
status: {}

简化部署3分tomcat6,将该配置写在tomcat6.yaml 文件中

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: tomcat6
  name: tomcat6
spec:
  replicas: 3
  selector:
    matchLabels:
      app: tomcat6
  template:
    metadata:
      labels:
        app: tomcat6
    spec:
      containers:
      - image: tomcat:6.0.53-jre8
        name: tomcat

执行，

kubectl apply -f tomcat6.yaml

[root@k8s-master k8s]# kubectl get pods
NAME                       READY   STATUS    RESTARTS   AGE
tomcat6-5f7ccf4cb9-m2hbz   1/1     Running   0          17s
tomcat6-5f7ccf4cb9-vv248   1/1     Running   0          17s
tomcat6-5f7ccf4cb9-wbhd7   1/1     Running   0          17s

获取pod的完整信息
kubectl get pod tomcat6-5f7ccf4cb9-m2hbz -o yaml

将一下配置写在 mypod.yaml 文件中

apiVersion: v1
kind: Pod
metadata:
  labels:
    app: tomcat6-new
  name: tomcat6-new
  namespace: default
spec:
  containers:
  - image: tomcat:6.0.53-jre8
    imagePullPolicy: IfNotPresent
    name: tomcat6-new
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: nginx

kubectl apply -f mypod.yaml

获取暴露service yaml配置

kubectl expose deployment tomcat6 --port=80 --target-port=8080 --type=NodePort --dry-run -o yaml

apiVersion: v1
kind: Service
metadata:
  labels:
    app: tomcat6
  name: tomcat6
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 8080
  selector:
    app: tomcat6
  type: NodePort
status:
  loadBalancer: {}

将部署与暴露yaml合并 --- 分割

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: tomcat6
  name: tomcat6
spec:
  replicas: 3
  selector:
    matchLabels:
      app: tomcat6
  template:
    metadata:
      labels:
        app: tomcat6
    spec:
      containers:
      - image: tomcat:6.0.53-jre8
        name: tomcat
---
apiVersion: v1
kind: Service
metadata:
  labels:
    app: tomcat6
  name: tomcat6
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 8080
  selector:
    app: tomcat6
  type: NodePort
status:
  loadBalancer: {}

先将以前的部署信息删除

 kubectl delete deployment.apps/tomcat6

重新执行部署与暴露

kubectl apply -f tomcat6-deployment.yaml

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