增删改查

增删改查

增

使用kubectl run 来增加一个pod，使用nginx的镜像，开放80端口，副本数为 1

[root@master ~]# kubectl run nginx-deploy --image=nginx:1.14-alpine --port=80 --replicas=1

kubectl run --generator=deployment/apps.v1 is DEPRECATED and will be removed in a future version. Use kubectl run --generator=run-pod/v1 or kubectl create instead.

deployment.apps/nginx-deploy created

查看

在第一次查看时，因为nginx镜像还需要时间拖拽下来，看到的是还在创建中

也可以使用 -o wide 来查看详细信息

[root@master ~]# kubectl get pods

NAME                            READY   STATUS              RESTARTS   AGE

nginx-deploy-7689897d8d-9dh5s   0/1     ContainerCreating   0          6s

[root@master ~]# kubectl get pods -o wide

NAME                            READY   STATUS              RESTARTS   AGE   IP       NODE                NOMINATED NODE   READINESS GATES

nginx-deploy-7689897d8d-9dh5s   0/1     ContainerCreating   0          12s   <none>   node03.kubernetes   <none>           <none>

当镜像拖拽完成后，pod就被创建成功了。

[root@master ~]# kubectl get deployment -o wide

NAME           READY   UP-TO-DATE   AVAILABLE   AGE   CONTAINERS     IMAGES              SELECTOR

nginx-deploy   1/1     1            1           31s   nginx-deploy   nginx:1.14-alpine   run=nginx-deploy

[root@master ~]# kubectl get pods -o wide

NAME                            READY   STATUS    RESTARTS   AGE   IP           NODE                NOMINATED NODE   READINESS GATES

nginx-deploy-7689897d8d-9dh5s   1/1     Running   0          50s   10.244.1.2   node03.kubernetes   <none>           <none>

能看到详细信息中，该pod所对应的容器呗创建在node03 上，并且ip地址是：10.244.1.2，目前只能在Kubernetes节点上才能访问，跳过之外是不能访问的。

[root@master ~]# curl 10.244.1.2

<!DOCTYPE html>

<html>

<head>

<title>Welcome to nginx!</title>

<style>

    body {

        width: 35em;

        margin: 0 auto;

        font-family: Tahoma, Verdana, Arial, sans-serif;

    }

</style>

</head>

<body>

<h1>Welcome to nginx!</h1>

<p>If you see this page, the nginx web server is successfully installed and

working. Further configuration is required.</p>

<p>For online documentation and support please refer to

<a href="http://nginx.org/">nginx.org</a>.<br/>

Commercial support is available at

<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>

</body>

</html>

service创建

事实上，上述的访问是不可取的，虽然可以访问，但容器的ip可能随时都会被修改或者其他情况导致该ip不可被访问。

此时就需要使用到 service 固定访问端点。使用 kubectl expose 来创建。

使用说明如下:

Usage:

  kubectl expose (-f FILENAME | TYPE NAME) [--port=port] [--protocol=TCP|UDP|SCTP] [--target-port=number-or-name]

[--name=name] [--external-ip=external-ip-of-service] [--type=type] [options]

注意： --target-port 表示容器上的端口，--name 表示service的名称，而 --port 表示service暴露的端口

--type=type 类型有： ClusterIP, NodePort, LoadBalancer, or ExternalName. Default is 'ClusterIP'.

下面开始创建：

[root@master ~]# kubectl expose deployment nginx-deploy --name=nginx --port=80 --target-port=80 --protocol=TCP

service/nginx exposed

查看

[root@master ~]# kubectl get service

NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)   AGE

kubernetes   ClusterIP   10.96.0.1        <none>        443/TCP   17h

nginx        ClusterIP   10.105.233.197   <none>        80/TCP    6s

测试访问:

这里的访问，直接访问刚刚创建的nginx service所对应的ip

[root@master ~]# curl 10.105.233.197

<!DOCTYPE html>

<html>

<head>

<title>Welcome to nginx!</title>

<style>

    body {

        width: 35em;

        margin: 0 auto;

        font-family: Tahoma, Verdana, Arial, sans-serif;

    }

</style>

</head>

<body>

<h1>Welcome to nginx!</h1>

<p>If you see this page, the nginx web server is successfully installed and

working. Further configuration is required.</p>

<p>For online documentation and support please refer to

<a href="http://nginx.org/">nginx.org</a>.<br/>

Commercial support is available at

<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>

</body>

</html>

这里需要用到coreDNS，来解析对应的service，这样外部即可访问。要配置coreDNS的域名解析才可。

测试其他pod通过series访问nginx

在master上查看kube-dns 信息

[root@master ~]# kubectl get service -n kube-system

NAME       TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)                  AGE

kube-dns   ClusterIP   10.96.0.10   <none>        53/UDP,53/TCP,9153/TCP   17h

创建一个pod，并使用 -it 参数进入到容器中。

[root@master ~]# kubectl run -i -t busybox --image=busybox --restart=Never

If you don't see a command prompt, try pressing enter.

/ #

查看 resolv.conf 文件中DNS

/ # cat /etc/resolv.conf

nameserver 10.96.0.10

search default.svc.cluster.local svc.cluster.local cluster.local localdomain

options ndots:5

尝试解析nginx service

/ # nslookup nginx

Server:		10.96.0.10

Address:	10.96.0.10:53

Name:	nginx.default.svc.cluster.local

Address: 10.105.233.197

/ # nslookup nginx.default.svc.cluster.local

Server:		10.96.0.10

Address:	10.96.0.10:53

*** Can't find nginx.default.svc.cluster.local: No answer

可以看到可以解析，尝试访问：

/ # wget -O - -q http://nginx

<!DOCTYPE html>

<html>

<head>

<title>Welcome to nginx!</title>

<style>

    body {

        width: 35em;

        margin: 0 auto;

        font-family: Tahoma, Verdana, Arial, sans-serif;

    }

</style>

</head>

<body>

<h1>Welcome to nginx!</h1>

<p>If you see this page, the nginx web server is successfully installed and

working. Further configuration is required.</p>

<p>For online documentation and support please refer to

<a href="http://nginx.org/">nginx.org</a>.<br/>

Commercial support is available at

<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>

</body>

</html>

可以直接在busybox中访问刚刚创建的nginx，没问题。

测试手动变更nginx对应的pod的ip

手动删除一下nginx的pod，这样，ip就会变更，然后在busybox中使用相同的service端点看能否访问。

[root@master ~]# kubectl get pods -o wide

NAME                            READY   STATUS    RESTARTS   AGE   IP           NODE                NOMINATED NODE   READINESS GATES

busybox                         1/1     Running   0          13m   10.244.2.2   node02.kubernetes   <none>           <none>

nginx-deploy-7689897d8d-9dh5s   1/1     Running   0          60m   10.244.1.2   node03.kubernetes   <none>           <none>

[root@master ~]# kubectl delete pod nginx-deploy-7689897d8d-9dh5s

pod "nginx-deploy-7689897d8d-9dh5s" deleted

[root@master ~]# kubectl get pods -o wide

NAME                            READY   STATUS    RESTARTS   AGE   IP           NODE                NOMINATED NODE   READINESS GATES

busybox                         1/1     Running   0          13m   10.244.2.2   node02.kubernetes   <none>           <none>

nginx-deploy-7689897d8d-lf8p7   1/1     Running   0          13s   10.244.3.2   node01.kubernetes   <none>           <none>

可以看到，nginx-deploy 的ip已经变更，下面测试访问

/ # wget -O - -q http://nginx

<!DOCTYPE html>

<html>

<head>

<title>Welcome to nginx!</title>

<style>

    body {

        width: 35em;

        margin: 0 auto;

        font-family: Tahoma, Verdana, Arial, sans-serif;

    }

</style>

</head>

<body>

<h1>Welcome to nginx!</h1>

<p>If you see this page, the nginx web server is successfully installed and

working. Further configuration is required.</p>

<p>For online documentation and support please refer to

<a href="http://nginx.org/">nginx.org</a>.<br/>

Commercial support is available at

<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>

</body>

</html>

依然可以访问。

pod和service之间的关系

查看 nginx 的service 对应的详细信息；

[root@master ~]# kubectl describe svc nginx

Name:              nginx

Namespace:         default

Labels:            run=nginx-deploy

Annotations:       <none>

Selector:          run=nginx-deploy

Type:              ClusterIP

IP:                10.105.233.197

Port:              <unset>  80/TCP

TargetPort:        80/TCP

Endpoints:         10.244.3.2:80

Session Affinity:  None

Events:            <none>

查看pod标签

[root@master ~]# kubectl get pods --show-labels

NAME                            READY   STATUS    RESTARTS   AGE   LABELS

busybox                         1/1     Running   0          30m   run=busybox

nginx-deploy-7689897d8d-lf8p7   1/1     Running   0          16m   pod-template-hash=7689897d8d,run=nginx-deploy

这里可以看出，因为nginx-deply的pod中，有nginx-deploy标签，而nginx的service的Selector选择的正式nginx-deploy标签，所以会被选中。

这就是pod和service之间的关系

service调度测试

创建一个两个副本的pod

[root@master ~]# kubectl run myapp --image=ikubernetes/myapp:v1 --replicas=2

kubectl run --generator=deployment/apps.v1 is DEPRECATED and will be removed in a future version. Use kubectl run --generator=run-pod/v1 or kubectl create instead.

deployment.apps/myapp created

[root@master ~]# kubectl get pods -o wide

NAME                            READY   STATUS    RESTARTS   AGE   IP           NODE                NOMINATED NODE   READINESS GATES

myapp-84cd4b7f95-kzf68          1/1     Running   0          77s   10.244.1.3   node03.kubernetes   <none>           <none>

myapp-84cd4b7f95-mx5vq          1/1     Running   0          77s   10.244.2.3   node02.kubernetes   <none>           <none>

在busybox中直接访问myapp

/ # wget -O - -q http://10.244.1.3

Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

/ # wget -O - -q http://10.244.1.3/hostname.html

myapp-84cd4b7f95-kzf68

/ # wget -O - -q http://10.244.2.3

Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

/ # wget -O - -q http://10.244.2.3/hostname.html

myapp-84cd4b7f95-mx5vq

创建myapp对应的service

[root@master ~]# kubectl expose deployment myapp --name=myapp --port=80

service/myapp exposed

[root@master ~]# kubectl get svc

NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)   AGE

kubernetes   ClusterIP   10.96.0.1        <none>        443/TCP   18h

myapp        ClusterIP   10.108.135.202   <none>        80/TCP    4s

nginx        ClusterIP   10.96.12.15      <none>        80/TCP    7m41s

在busybox中访问service

/ # wget -O - -q http://myapp

Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

/ # wget -O - -q http://myapp/hostname.html

/ # wget -O - -q http://myapp/hostname.html

myapp-84cd4b7f95-mx5vq

/ # wget -O - -q http://myapp/hostname.html

myapp-84cd4b7f95-kzf68

可以看到，当直接访问对应的service的时候，会有一个轮训的效果，这样就起到了负载均衡效果。

动态扩容pod

刚刚创建的myapp是2个副本，这个副本数是可以动态扩容的.

可以使用 kubectl scale 来扩容

Usage:

  kubectl scale [--resource-version=version] [--current-replicas=count] --replicas=COUNT (-f FILENAME | TYPE NAME)

[options]

操作：

[root@master ~]# kubectl scale --replicas=5 deployment myapp

deployment.extensions/myapp scaled

[root@master ~]# kubectl get pods

NAME                            READY   STATUS    RESTARTS   AGE

busybox                         1/1     Running   0          46m

myapp-84cd4b7f95-kzf68          1/1     Running   0          9m56s

myapp-84cd4b7f95-mx5vq          1/1     Running   0          9m56s

myapp-84cd4b7f95-nk8l2          1/1     Running   0          25s

myapp-84cd4b7f95-srlt2          1/1     Running   0          25s

myapp-84cd4b7f95-tgsdd          1/1     Running   0          25s

nginx-deploy-7689897d8d-lf8p7   1/1     Running   0          32m

可以看到已经被调动成功，添加到5个副本数。

同时在看service

/ # while true; do wget -O - -q http://myapp/hostname.html;sleep 1;done

myapp-84cd4b7f95-kzf68

myapp-84cd4b7f95-mx5vq

myapp-84cd4b7f95-tgsdd

myapp-84cd4b7f95-mx5vq

myapp-84cd4b7f95-kzf68

myapp-84cd4b7f95-srlt2

myapp-84cd4b7f95-srlt2

myapp-84cd4b7f95-srlt2

myapp-84cd4b7f95-nk8l2

myapp-84cd4b7f95-mx5vq

myapp-84cd4b7f95-mx5vq

myapp-84cd4b7f95-tgsdd

myapp-84cd4b7f95-nk8l2

myapp-84cd4b7f95-srlt2

myapp-84cd4b7f95-mx5vq

myapp-84cd4b7f95-tgsdd

myapp-84cd4b7f95-kzf68

在service中，已经可以被调度了，并且也是负载均衡效果。

这种添加或者减少，直接操作即可。

滚动升级

可以在线的实现灰度、蓝绿等滚动发布升级。

刚刚创建的myapp是v1版本，下面升级到v2版本，然后查看效果。

使用 kubectl set image 来操作

Usage:

  kubectl set image (-f FILENAME | TYPE NAME) CONTAINER_NAME_1=CONTAINER_IMAGE_1 ... CONTAINER_NAME_N=CONTAINER_IMAGE_N

[options]

操作：

[root@master ~]# kubectl set image deployment myapp myapp=ikubernetes/myapp:v2

deployment.extensions/myapp image updated

[root@master ~]# kubectl rollout status deployment myapp

Waiting for deployment "myapp" rollout to finish: 2 out of 3 new replicas have been updated...

Waiting for deployment "myapp" rollout to finish: 2 out of 3 new replicas have been updated...

Waiting for deployment "myapp" rollout to finish: 2 out of 3 new replicas have been updated...

Waiting for deployment "myapp" rollout to finish: 1 old replicas are pending termination...

Waiting for deployment "myapp" rollout to finish: 1 old replicas are pending termination...

deployment "myapp" successfully rolled out

可以使用 kubectl rollout status 来跟踪容器的变化

/ # while true; do wget -O - -q http://myapp;sleep 1;done

Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a>

这里也可以看到访问所带来的变化。

同时，因为版本个更新，所有myapp所有的对应的名称的hash值都变化了，因为都被删除后重新创建的。

[root@master ~]# kubectl get pods

NAME                            READY   STATUS    RESTARTS   AGE

busybox                         1/1     Running   0          54m

myapp-746644f8d6-96q2j          1/1     Running   0          2m3s

myapp-746644f8d6-qmqdz          1/1     Running   0          114s

myapp-746644f8d6-xj72g          1/1     Running   0          107s

nginx-deploy-7689897d8d-lf8p7   1/1     Running   0          40m

失败回滚

使用 kubectl rollout 来操作

Usage:

  kubectl rollout SUBCOMMAND [options]

操作：

[root@master ~]# kubectl rollout undo deployment myapp

deployment.extensions/myapp rolled back

[root@master ~]# kubectl get pods

NAME                            READY   STATUS    RESTARTS   AGE

busybox                         1/1     Running   0          57m

myapp-84cd4b7f95-44qch          1/1     Running   0          54s

myapp-84cd4b7f95-fzvsd          1/1     Running   0          55s

myapp-84cd4b7f95-mlphg          1/1     Running   0          52s

nginx-deploy-7689897d8d-lf8p7   1/1     Running   0          44m

查看访问：

while true; do wget -O - -q http://myapp;sleep 1;done

Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

开通集群外访问

上面的所有操作，都仅限于kubernetes集群内部的节点所有资源可以访问。

需要修改service中的类型，来开通访问。

[root@master ~]# kubectl edit svc myapp

# Please edit the object below. Lines beginning with a '#' will be ignored,

# and an empty file will abort the edit. If an error occurs while saving this file will be

# reopened with the relevant failures.

#

apiVersion: v1

kind: Service

metadata:

  creationTimestamp: "2019-07-10T02:56:26Z"

  labels:

    run: myapp

  name: myapp

  namespace: default

  resourceVersion: "105517"

  selfLink: /api/v1/namespaces/default/services/myapp

  uid: 15e48fde-3242-4871-8113-0ae5b91cd634

spec:

  clusterIP: 10.108.135.202

  externalTrafficPolicy: Cluster

  ports:

  - nodePort: 31441

    port: 80

    protocol: TCP

    targetPort: 80

  selector:

    run: myapp

  sessionAffinity: None

  type: NodePort  # 这里修改

status:

  loadBalancer: {}

把 type: ClusterIP 修改为 type: NodePort 。

然后报错退出，再次查看myapp的service：

[root@master ~]# kubectl get svc

NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE

kubernetes   ClusterIP   10.96.0.1        <none>        443/TCP        18h

myapp        NodePort    10.108.135.202   <none>        80:31441/TCP   21m

nginx        ClusterIP   10.96.12.15      <none>        80/TCP         29m

能看到myapp的port列中， 80: 31441 ，此时kubernetes中所有节点的31441端口都可以被访问到myapp中的nginx容器

找一台kubernetes集群外的机器访问测试：

[root@guanwang ~]# ip a | grep 255

    inet 10.0.20.140/24 brd 10.0.20.255 scope global bond0

[root@guanwang ~]# curl 10.0.20.20:31441

Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

[root@guanwang ~]# curl 10.0.20.21:31441

Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

[root@guanwang ~]# curl 10.0.20.22:31441

Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

[root@guanwang ~]# curl 10.0.20.23:31441

Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

真实的工作中，极少有机会直接操作上述所有的命令，都会通过ymal格式的配置文件来操作kubernetes中的所有资源。

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