4、kubernetes应用入门

kubectl controls the Kubernetes cluster manager.

 Find more information at: https://kubernetes.io/docs/reference/kubectl/overview/

Basic Commands (Beginner):

  create         Create a resource from a file or from stdin.  //增

  expose         Take a replication controller, service, deployment or pod and expose it as a new Kubernetes Service

  run            Run a particular image on the cluster

  set            Set specific features on objects

Basic Commands (Intermediate):

  explain        Documentation of resources

  get            Display one or many resources    //查

  edit           Edit a resource on the server    //改

  delete         Delete resources by filenames, stdin, resources and names, or by resources and label selector   //删除

Deploy Commands:

  rollout        Manage the rollout of a resource  //滚动

  scale          Set a new size for a Deployment, ReplicaSet, Replication Controller, or Job  //手动改变应用程序的规模

  autoscale      Auto-scale a Deployment, ReplicaSet, or ReplicationController  //自动改变，即创建HPA

Cluster Management Commands:  //集群管理

  certificate    Modify certificate resources.

  cluster-info   Display cluster info   //集群信息

  top            Display Resource (CPU/Memory/Storage) usage.

  cordon         Mark node as unschedulable  //标记一个节点不可被调用

  uncordon       Mark node as schedulable   //标记节点可被调用

  drain          Drain node in preparation for maintenance

  taint          Update the taints on one or more nodes  //给节点增加污点，作用是控制是否被调用

Troubleshooting and Debugging Commands:

  describe       Show details of a specific resource or group of resources  //描述资源的详细信息，例如 master ~]# kubectl describe node node01

  logs           Print the logs for a container in a pod

  attach         Attach to a running container

  exec           Execute a command in a container

  port-forward   Forward one or more local ports to a pod

  proxy          Run a proxy to the Kubernetes API server

  cp             Copy files and directories to and from containers.

  auth           Inspect authorization

Advanced Commands:

  diff           Diff live version against would-be applied version

  apply          Apply a configuration to a resource by filename or stdin

  patch          Update field(s) of a resource using strategic merge patch

  replace        Replace a resource by filename or stdin

  wait           Experimental: Wait for a specific condition on one or many resources.

  convert        Convert config files between different API versions

  kustomize      Build a kustomization target from a directory or a remote url.

Settings Commands:

  label          Update the labels on a resource

  annotate       Update the annotations on a resource

  completion     Output shell completion code for the specified shell (bash or zsh)

Other Commands:

  api-resources  Print the supported API resources on the server

  api-versions   Print the supported API versions on the server, in the form of "group/version"

  config         Modify kubeconfig files

  plugin         Provides utilities for interacting with plugins.

  version        Print the client and server version information

Usage:

  kubectl [flags] [options]

Use "kubectl <command> --help" for more information about a given command.

Use "kubectl options" for a list of global command-line options (applies to all commands).

描述一个资源的详细信息

[root@master ~]# kubectl describe node master

Name:               master

Roles:              master

Labels:             beta.kubernetes.io/arch=amd64

                    beta.kubernetes.io/os=linux

                    kubernetes.io/arch=amd64

                    kubernetes.io/hostname=master

                    kubernetes.io/os=linux

                    node-role.kubernetes.io/master=

Annotations:        flannel.alpha.coreos.com/backend-data: {"VtepMAC":"2e:6c:70:78:ed:70"}

                    flannel.alpha.coreos.com/backend-type: vxlan

                    flannel.alpha.coreos.com/kube-subnet-manager: true

                    flannel.alpha.coreos.com/public-ip: 192.168.184.141

                    kubeadm.alpha.kubernetes.io/cri-socket: /var/run/dockershim.sock

                    node.alpha.kubernetes.io/ttl:

                    volumes.kubernetes.io/controller-managed-attach-detach: true

CreationTimestamp:  Fri,  May  :: +

Taints:             node-role.kubernetes.io/master:NoSchedule   //表示只要不是master的组件都不能调度到master上

Unschedulable:      false

Conditions:

  Type             Status  LastHeartbeatTime                 LastTransitionTime                Reason                       Message

  ----             ------  -----------------                 ------------------                ------                       -------

  MemoryPressure   False   Mon,  Jun  :: +   Fri,  May  :: +   KubeletHasSufficientMemory   kubelet has sufficient memory available

  DiskPressure     False   Mon,  Jun  :: +   Fri,  May  :: +   KubeletHasNoDiskPressure     kubelet has no disk pressure

  PIDPressure      False   Mon,  Jun  :: +   Fri,  May  :: +   KubeletHasSufficientPID      kubelet has sufficient PID available

  Ready            True    Mon,  Jun  :: +   Mon,  Jun  :: +   KubeletReady                 kubelet is posting ready status

Addresses:

  InternalIP:  192.168.184.141

  Hostname:    master

Capacity:

 cpu:

 ephemeral-storage:  12786Mi

 hugepages-1Gi:

 hugepages-2Mi:

 memory:             1867048Ki

 pods:

Allocatable:

 cpu:

 ephemeral-storage:

 hugepages-1Gi:

 hugepages-2Mi:

 memory:             1764648Ki

 pods:

System Info:

 Machine ID:                 45c658713b3b423387314d097b36aa61

 System UUID:                7C8C4D56--E896-C85E-040A2FCEF804

 Boot ID:                    474da659--4a63-a5f9-2e436260b3d2

 Kernel Version:             3.10.-.el7.x86_64

 OS Image:                   CentOS Linux  (Core)

 Operating System:           linux

 Architecture:               amd64

 Container Runtime Version:  docker://18.9.6

 Kubelet Version:            v1.14.2

 Kube-Proxy Version:         v1.14.2

PodCIDR:                     10.244.0.0/

Non-terminated Pods:         ( in total)

  Namespace                  Name                              CPU Requests  CPU Limits  Memory Requests  Memory Limits  AGE

  ---------                  ----                              ------------  ----------  ---------------  -------------  ---

  kube-system                coredns-fb8b8dccf-42b7j           100m (%)      (%)      70Mi (%)        170Mi (%)     3d1h

  kube-system                coredns-fb8b8dccf-bjv95           100m (%)      (%)      70Mi (%)        170Mi (%)     3d1h

  kube-system                etcd-master                        (%)         (%)       (%)            (%)         3d1h

  kube-system                kube-apiserver-master             250m (%)      (%)       (%)            (%)         3d1h

  kube-system                kube-controller-manager-master    200m (%)      (%)       (%)            (%)         3d1h

  kube-system                kube-flannel-ds-amd64-w4jfh       100m (%)     100m (%)   50Mi (%)        50Mi (%)      2d18h

  kube-system                kube-proxy-f88gd                   (%)         (%)       (%)            (%)         3d1h

  kube-system                kube-scheduler-master             100m (%)      (%)       (%)            (%)         3d1h

Allocated resources:

  (Total limits may be over  percent, i.e., overcommitted.)

  Resource           Requests     Limits

  --------           --------     ------

  cpu                850m (%)   100m (%)

  memory             190Mi (%)  390Mi (%)

  ephemeral-storage   (%)        (%)

Events:

  Type    Reason                   Age   From             Message

  ----    ------                   ----  ----             -------

  Normal  Starting                 14m   kubelet, master  Starting kubelet.

  Normal  NodeHasSufficientMemory  14m   kubelet, master  Node master status is now: NodeHasSufficientMemory

  Normal  NodeHasNoDiskPressure    14m   kubelet, master  Node master status is now: NodeHasNoDiskPressure

  Normal  NodeHasSufficientPID     14m   kubelet, master  Node master status is now: NodeHasSufficientPID

  Normal  NodeNotReady             14m   kubelet, master  Node master status is now: NodeNotReady

  Normal  NodeAllocatableEnforced  14m   kubelet, master  Updated Node Allocatable limit across pods

  Normal  NodeReady                14m   kubelet, master  Node master status is now: NodeReady

[root@master ~]# kubectl version  //查看客户端和服务器端的版本

Client Version: version.Info{Major:"", Minor:"", GitVersion:"v1.14.2", GitCommit:"66049e3b21efe110454d67df4fa62b08ea79a19b", GitTreeState:"clean", 
                BuildDate:"2019-05-16T16:23:09Z", GoVersion:"go1.12.5", Compiler:"gc", Platform:"linux/amd64"}

Server Version: version.Info{Major:"", Minor:"", GitVersion:"v1.14.2", GitCommit:"66049e3b21efe110454d67df4fa62b08ea79a19b", GitTreeState:"clean", 
                BuildDate:"2019-05-16T16:14:56Z", GoVersion:"go1.12.5", Compiler:"gc", Platform:"linux/amd64"}

[root@master ~]# kubectl cluster-info   //查看集群信息

Kubernetes master is running at https://192.168.184.141:6443   //向外输出的API Server地址

KubeDNS is running at https://192.168.184.141:6443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy  
  //相当于CoreDNS，运行获取路径时，从集群外部访问的执行端口转发的代理的访问方式

To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.

Usage:

  kubectl expose (-f FILENAME | TYPE NAME) [--port=port] [--protocol=TCP|UDP|SCTP] [--target-port=number-or-name]   //[--port=port]指service的端口
[--name=name] [--external-ip=external-ip-of-service] [--type=type] [options]   //[--name=name]是service的名称，[--type=type]是service的类型

master ~]# kubectl expose deployment nginx-deploy --name=nginx --port=80 --target-port=80 --protocol=TCP 
service/nginx exposed  //nginx是服务名称，是nginx-deploy创建的pod资源
//deployment是控制器，将控制器相关的pod资源即nginx-deployment创建为一个服务，服务名是nginx。

[root@master ~]# kubectl get svc  //svc是service的缩写，查看创建的服务

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

kubernetes   ClusterIP   10.96.0.1     <none>        /TCP   3d15h

nginx        ClusterIP   10.96.75.49   <none>        80/TCP    2m41s 

service是为pod提供一个固定访问端点，但这个端点不支持外部访问，只能在集群内部的节点上才能被访问，这种端点大多时候是被pod客户端访问的。
pod客户端在访问服务时，是可以基于service的名称来访问的(IP地址是动态生成的)，但是pod客户端必须能解析这个service名称。
解析时就需要依赖CoreDNS服务。CoreDNS地址是可以查询的，但一般并不会直接使用地址，而是使用CoreDNS的服务名称。

master ~]# kubectl get pods -n kube-system -o wide

NAME                             READY   STATUS    RESTARTS   AGE     IP                NODE     NOMINATED NODE   READINESS GATES

coredns-fb8b8dccf-42b7j          /     Running             3d15h   10.244.0.2        master   <none>           <none>

coredns-fb8b8dccf-bjv95          /     Running             3d15h   10.244.0.3        master   <none>           <none>

etcd-master                      /     Running             3d15h   192.168.184.141   master   <none>           <none>

kube-apiserver-master            /     Running             3d15h   192.168.184.141   master   <none>           <none>

kube-controller-manager-master   /     Running             3d15h   192.168.184.141   master   <none>           <none>

kube-flannel-ds-amd64-4z7ht      /     Running             18h     192.168.184.144   node03   <none>           <none>

kube-flannel-ds-amd64-k4rxq      /     Running             18h     192.168.184.142   node01   <none>           <none>

kube-flannel-ds-amd64-w4jfh      /     Running             3d8h    192.168.184.141   master   <none>           <none>

kube-flannel-ds-amd64-ztbm6      /     Running             2d21h   192.168.184.143   node02   <none>           <none>

kube-proxy-f88gd                 /     Running             3d15h   192.168.184.141   master   <none>           <none>

kube-proxy-kvd9x                 /     Running             18h     192.168.184.144   node03   <none>           <none>

kube-proxy-qqhpx                 /     Running             18h     192.168.184.142   node01   <none>           <none>

kube-proxy-zsnz5                 /     Running             2d21h   192.168.184.143   node02   <none>           <none>

kube-scheduler-master            /     Running             3d15h   192.168.184.141   master   <none>           <none>

[root@master ~]# kubectl get svc -n kube-system  //查看kube-system名称空间中的服务

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

kube-dns   ClusterIP   10.96.0.10   <none>        /UDP,/TCP,/TCP   3d15h

为了演示效果CoreDNS解析效果，再启动一个pod作为客户端使用

[root@master ~]# kubectl run client --image=busybox --replicas= -it --restart=Never

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

/ # cat /etc/resolv.conf

nameserver 10.96.0.10   //IP解析地址指向10.96.0.10

search default.svc.cluster.local svc.cluster.local cluster.local  //svc.cluster.local表示k8s集群的本地pod资源的特定后缀，default表示pod所属的名称空间的名字，
 options ndots: / #                                          //所以如果基于服务的名称进行解析时，一定要使用完整的服务名称。如果服务名称不完整，搜索域是不一样的

master ~]# yum install bind-utils

master ~]# dig -t A nginx.default.svc.cluster.local @10.96.0.10   //根据服务全名，通过CoreDNS服务将service的IP解析出来

; <<>> DiG 9.9.-RedHat-9.9.-.el7_6 <<>> -t A nginx.default.svc.cluster.local @10.96.0.10

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id:

;; flags: qr aa rd; QUERY: , ANSWER: , AUTHORITY: , ADDITIONAL:

;; WARNING: recursion requested but not available

;; OPT PSEUDOSECTION:

; EDNS: version: , flags:; udp:

;; QUESTION SECTION:

;nginx.default.svc.cluster.local. IN    A

;; ANSWER SECTION:

nginx.default.svc.cluster.local. 5 IN    A    10.96.75.49   //根据service服务(nginx)名称将service的IP解析出来

;; Query time:  msec

;; SERVER: 10.96.0.10#(10.96.0.10)

;; WHEN: Tue Jun  :: CST

;; MSG SIZE  rcvd: 

[root@master ~]# kubectl run client --image=busybox --replicas= -it --restart=Never

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

/ # cat /etc/resolv.conf

nameserver 10.96.0.10

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

options ndots:

/ # wget nginx

Connecting to nginx (10.96.75.49:80)   //根据service名称解析出来service的IP

index.html           % |***********************************************************************************************|     :: ETA

/ # wget -O - -q http://nginx:80/  //此时这里的80端口被调度到pod的port上

<!DOCTYPE html>

<html>

<head>

<title>Welcome to nginx!</title>

</html>

下面将pod手动宕机，测试使用同一个service名称(nginx)是否还可以访问

[root@master ~]# kubectl get pods  //查询pod的名称

NAME                           READY   STATUS    RESTARTS   AGE

client                         /     Running             36m

nginx-deploy-55d8d67cf-tfppt   /     Running             5h35m

[root@master ~]# kubectl delete pods nginx-deploy-55d8d67cf-tfppt   //删除pod

pod "nginx-deploy-55d8d67cf-tfppt" deleted

[root@master ~]# kubectl get pods   再次查看，控制器已经新建了一个pod

NAME                           READY   STATUS              RESTARTS   AGE

client                         /     Running                       36m

nginx-deploy-55d8d67cf-hlj9v   /     ContainerCreating             11s

[root@master ~]# kubectl get pods   //新建的pod已经运行

NAME                           READY   STATUS    RESTARTS   AGE

client                         /     Running             37m

nginx-deploy-55d8d67cf-hlj9v   /     Running             37s

/ # wget -O - -q http://nginx:80/   //再次使用service服务的名称进行访问nginx服务，还是可以访问的，这就是通过标签和标签选择器关联pod资源，而不是基于IP地址来选择的。

<!DOCTYPE html>

<html>

<head>

<title>Welcome to nginx!</title>

</body>

master ~]# kubectl expose deployment nginx-deploy --name=nginx --port=80 --target-port=80 --protocol=TCP 
上述实验说明了只要是nginx-deploy创建的pod，一律都纳入到服务的后端中去，这就是service可以为pod提供固定的访问端点。
service是iptables规则或者ipvs规则

[root@master ~]# kubectl get pods -o wide  //目前服务运行在node01上，但是在其他节点(node02或node03)都是可以查看相关规则的

NAME                           READY   STATUS    RESTARTS   AGE     IP           NODE     NOMINATED NODE   READINESS GATES

client                         /     Running             6h12m   10.244.1.3   node03   <none>           <none>

nginx-deploy-55d8d67cf-hlj9v   /     Running             5h36m   10.244.3.2   node01   <none>           <none> 

[root@master ~]# kubectl get svc  //主要关注的不是pod自身，而是svc，service生成后即nginx会生成iptables或ipvs规则，把所有访问10.96.75.49:80的都调度至

NAME         TYPE        CLUSTER-IP    EXTERNAL-IP   PORT(S)   AGE          //nginx用标签选择器关联到的各pod后端。
kubernetes ClusterIP 10.96.0.1 <none> /TCP 3d22h nginx ClusterIP 10.96.75.49 <none> 80/TCP 6h45m

如何查看标签选择器关联到哪些客户端？

[root@master ~]# kubectl describe svc nginx    //下面显示的资源都是可以被改变的

Name:              nginx

Namespace:         default

Labels:            run=nginx-deploy

Annotations:       <none>

Selector:          run=nginx-deploy   //选择器选择那些所有拥有run标签，且值=nginx-deploy的pod资源

Type:              ClusterIP

IP:                10.96.75.49  //比如IP地址改变后，解析结果也会自动修改，这里的变化会立即CoreDNS的解析记录当中，如果把这个服务删除了，这个地址也是发生变化的

Port:              <unset>  /TCP

TargetPort:        80/TCP

Endpoints:         10.244.3.2:80  //如果pod资源被删除，这里会发生相应的变化

Session Affinity:  None

Events:            <none>

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

NAME                           READY   STATUS    RESTARTS   AGE     LABELS

client                         /     Running             7h4m    run=client

nginx-deploy-55d8d67cf-hlj9v   /     Running             6h27m   pod-template-hash=55d8d67cf,run=nginx-deploy 
   //当此标签被删除时，再创建是依然要有此标签才能被选中，而不是根据IP地址被选中

首先使用kubectl run创建一个pod，比如这个pod运行的是nginx，此时nginx只能对集群内的节点提供访问功能，集群外的节点是无法访问的；所以就需要创建一个service，由service通过pod的标签关联pod，然后对集群外部提供服务。

以上就是service的意义

控制器是根据标签选择器来关联到pod资源上的
[root@master]# kubectl describe deployment nginx-deploy

Name:                   nginx-deploy

Namespace:              default

CreationTimestamp:      Tue,  Jun  :: +

Labels:                 run=nginx-deploy

Annotations:            deployment.kubernetes.io/revision: 

Selector:               run=nginx-deploy

Replicas:                desired |  updated |  total |  available |  unavailable

StrategyType:           RollingUpdate

MinReadySeconds:

RollingUpdateStrategy:  % max unavailable, % max surge

Pod Template:

  Labels:  run=nginx-deploy

  Containers:

   nginx-deploy:

    Image:        nginx:1.14-alpine

    Port:         /TCP

    Host Port:    /TCP

    Environment:  <none>

    Mounts:       <none>

  Volumes:        <none>

Conditions:

  Type           Status  Reason

  ----           ------  ------

  Progressing    True    NewReplicaSetAvailable

  Available      True    MinimumReplicasAvailable

OldReplicaSets:  <none>

NewReplicaSet:   nginx-deploy-55d8d67cf (/ replicas created)

Events:          <none>

NAME           READY   UP-TO-DATE   AVAILABLE   AGE

myapp          /                            5m38s

nginx-deploy   /                            10d

[root@master ~]# kubectl get deployment -w   //-w表示监控

NAME           READY   UP-TO-DATE   AVAILABLE   AGE

myapp          /                            95s

nginx-deploy   /                            10d

NAME                           READY   STATUS      RESTARTS   AGE     IP           NODE     NOMINATED NODE   READINESS GATES

client                         /     Error                 9d      <none>       node03   <none>           <none>

client1                        /     Completed             9d      10.244.2.3   node02   <none>           <none>

myapp-5bc569c47d-24qfh         1/1     Running     0          7m29s   10.244.2.4   node02   <none>           <none>

myapp-5bc569c47d-7ql96         1/1     Running     0          7m29s   10.244.1.4   node03   <none>           <none>

nginx-deploy-55d8d67cf-hlj9v   /     Running               9d      10.244.3.5   node01   <none>           <none>

[root@master ~]# kubectl run client2 --image=busybox --replicas=1 -it --restart=Never //应该为pod提供固定的访问端点，即service

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

/ # wget -O - -q 10.244.2.4

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

/ # wget -O - -q 10.244.1.4

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

/ # wget -O - -q 10.244.1.4/hostname.html

myapp-5bc569c47d-7ql96

/ # wget -O - -q 10.244.2.4/hostname.html

myapp-5bc569c47d-24qfh

[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>        /TCP   13d

myapp        ClusterIP   10.96.152.130   <none>        80/TCP    7s

nginx        ClusterIP   10.96.75.49     <none>        /TCP    9d

/ # wget -O - -q myapp

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

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

myapp-5bc569c47d-7ql96

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

myapp-5bc569c47d-24qfh

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

myapp-5bc569c47d-24qfh

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

myapp-5bc569c47d-7ql96

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

myapp-5bc569c47d-24qfh

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

myapp-5bc569c47d-7ql96

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

myapp-5bc569c47d-7ql96

myapp-5bc569c47d-24qfh

myapp-5bc569c47d-24qfh

myapp-5bc569c47d-7ql96

myapp-5bc569c47d-24qfh

myapp-5bc569c47d-7ql96

Usage:

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

master ~]# kubectl scale --replicas= deployment myapp   //将控制器myapp的副本数量增加到5

deployment.extensions/myapp scaled

[root@master ~]# kubectl get pods   //查看副本是五个

NAME                           READY   STATUS             RESTARTS   AGE

client                         /     Error                        9d

client1                        /     Completed                    9d

client2                        /     Running                      65m

myapp-5bc569c47d-24qfh         1/1     Running            0          75m

myapp-5bc569c47d-7ql96         1/1     Running            0          75m

myapp-5bc569c47d-bdpxf         1/1     Running            0          69s

myapp-5bc569c47d-ftrgc         1/1     Running            0          69s

myapp-5bc569c47d-qlk7f         0/1     Running            0          69s

nginx-deploy-55d8d67cf-hlj9v   /     Running                      9d

/ # while true; do wget -O - -q myapp/hostname.html; sleep ; done  //这里可以把5个pod都可以访问到

myapp-5bc569c47d-ftrgc

myapp-5bc569c47d-24qfh

myapp-5bc569c47d-ftrgc

myapp-5bc569c47d-bdpxf

myapp-5bc569c47d-qlk7f

myapp-5bc569c47d-qlk7f

myapp-5bc569c47d-7ql96

myapp-5bc569c47d-bdpxf

myapp-5bc569c47d-qlk7f

myapp-5bc569c47d-qlk7f

myapp-5bc569c47d-7ql96

[root@master ~]# kubectl get pods

NAME                           READY   STATUS      RESTARTS   AGE

client                         /     Error                 9d

client1                        /     Completed             9d

client2                        /     Error                 78m

client3                        /     Running               2m46s

myapp-5bc569c47d-24qfh         1/1     Running     0          88m

myapp-5bc569c47d-7ql96         1/1     Running     0          88m

myapp-5bc569c47d-bdpxf         1/1     Running     0          14m

nginx-deploy-55d8d67cf-hlj9v   /     Running               9d

/ # while true; do wget -O - -q myapp/hostname.html; sleep ; done   //缩减后只调度剩下三个pod

myapp-5bc569c47d-24qfh

myapp-5bc569c47d-7ql96

myapp-5bc569c47d-7ql96

myapp-5bc569c47d-bdpxf

myapp-5bc569c47d-24qfh

myapp-5bc569c47d-bdpxf

/ # while true; do wget -O - -q myapp; sleep ; 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: 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>

[root@master ~]# kubectl get pods   //首先查看升级哪些pod

NAME                           READY   STATUS      RESTARTS   AGE

client                         /     Error                 9d

client1                        /     Completed             9d

client2                        /     Error                 119m

client3                        /     Running               43m

myapp-5bc569c47d-24qfh         /     Running               129m

myapp-5bc569c47d-7ql96         /     Running               129m

myapp-5bc569c47d-bdpxf         /     Running               55m

nginx-deploy-55d8d67cf-hlj9v   /     Running               9d

Name:               myapp-5bc569c47d-24qfh

Namespace:          default

Priority:

PriorityClassName:  <none>

Node:               node02/192.168.184.143

Start Time:         Fri,  Jun  :: +

Labels:             pod-template-hash=5bc569c47d

                    run=myapp

Annotations:        <none>

Status:             Running

IP:                 10.244.2.4

Controlled By:      ReplicaSet/myapp-5bc569c47d

Containers:  //容器名称

  myapp:

    Container ID:   docker://698843132d3a70585e8065470f97ae1d74ece31ae04749c57b9e93a66fe99d91

    Image:          ikubernetes/myapp:v1

    Image ID:       docker-pullable://ikubernetes/myapp@sha256:9c3dc30b5219788b2b8a4b065f548b922a34479577befb54b03330999d30d513

    Port:           <none>

    Host Port:      <none>

    State:          Running

      Started:      Fri,  Jun  :: +

    Ready:          True

    Restart Count:

    Environment:    <none>

    Mounts:

      /var/run/secrets/kubernetes.io/serviceaccount from default-token-fckpp (ro)

Conditions:

  Type              Status

  Initialized       True

  Ready             True

  ContainersReady   True

  PodScheduled      True

Volumes:

  default-token-fckpp:

    Type:        Secret (a volume populated by a Secret)

    SecretName:  default-token-fckpp

    Optional:    false

QoS Class:       BestEffort

Node-Selectors:  <none>

Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s

                 node.kubernetes.io/unreachable:NoExecute for 300s

Events:          <none>

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

deployment.extensions/myapp image updated

[root@master ~]# kubectl rollout status deployment myapp  //这里显示已经更新完成

deployment "myapp" successfully rolled out

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

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>

[root@master ~]# kubectl get pods

NAME                           READY   STATUS      RESTARTS   AGE

client                         /     Error                 10d

client1                        /     Completed             9d

client2                        /     Error                 3h45m

client3                        /     Running               149m

myapp-86984b4c7c-24tmb         1/1     Running     0          97m

myapp-86984b4c7c-clqhw         1/1     Running     0          96m

myapp-86984b4c7c-crzfj         1/1     Running     0          97m

nginx-deploy-55d8d67cf-hlj9v   /     Running               10d

Examples:

  # Rollback to the previous deployment

  kubectl rollout undo deployment/abc

  # Check the rollout status of a daemonset

  kubectl rollout status daemonset/foo

Available Commands:

  history     View rollout history

  pause       Mark the provided resource as paused

  resume      Resume a paused resource

  status      Show the status of the rollout

  undo        Undo a previous rollout

Usage:

  kubectl rollout SUBCOMMAND [options]

Use "kubectl <command> --help" for more information about a given command.

Use "kubectl options" for a list of global command-line options (applies to all commands).

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

deployment.extensions/myapp rolled back

[root@master ~]# kubectl get pods

NAME                           READY   STATUS        RESTARTS   AGE

client3                        /     Running                 157m

myapp-5bc569c47d-5cdpw         1/1     Running       0          7s

myapp-5bc569c47d-c4gr2         1/1     Running       0          11s

myapp-5bc569c47d-njr5w         1/1     Running       0          9s    //上述三个是运行回滚后的版本的pod

myapp-86984b4c7c-24tmb         0/1     Terminating   0          105m  //结束此前版本

nginx-deploy-55d8d67cf-hlj9v   /     Running                 10d

/ # while true; do wget -O - -q myapp; sleep ; done  //此时已经运行的是V1版本了

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

# 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: "2019-06-14T02:35:03Z"

  labels:

    run: myapp

  name: myapp

  namespace: default

  resourceVersion: ""

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

  uid: 039652cc-8e4d-11e9-a017-000c29cef804

spec:

  clusterIP: 10.96.152.130

  ports:

  - port:

    protocol: TCP

    targetPort:

  selector:

    run: myapp

  sessionAffinity: None

  type: ClusterIP   --> 将ClusterIP 修改为NodePort

status:

  loadBalancer: {}

[root@master ~]# kubectl get svc

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

kubernetes   ClusterIP   10.96.0.1       <none>        /TCP        13d

myapp        NodePort    10.96.152.130   <none>        :/TCP   3h15m  //30327是每一个节点的这个端口都可以访问myapp

nginx        ClusterIP   10.96.75.49     <none>        /TCP         10d