Kubernetes 學習4 kubernetes應用快速入門

時間 2019-11-19

標籤 kubernetes 學習應用快速入門简体版

原文原文鏈接

1、相關命令html

　　一、kubectlnode

　　　　經過鏈接api server 進行各k8s對象資源的增刪改查,如pod，service，controller(控制器)，咱們經常使用的pod控制器replicaset，deployment,statefulet，daemonset，job，cronjob等，甚至node都是對象。linux

[root@k8smaster ~]# kubectl --help
kubectl controls the Kubernetes cluster manager. 

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

Basic Commands (Beginner): #新手用的命令
  create  #增       Create a resource from a file or from stdin.
  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):  #中級的基礎命令
  explain        Documentation of resources
  get   #查         Display one or many resources
  edit #改          Edit a resource on the server
  delete  #刪       Delete resources by filenames, stdin, resources and names, or by resources and label selector

Deploy Commands: #部署命令
  rollout  #滾動，回滾      Manage the rollout of a resource
  scale    #改變應用程序的規模      Set a new size for a Deployment, ReplicaSet, Replication Controller, or Job
  autoscale #自動改變，就是建立HPA的     Auto-scale a Deployment, ReplicaSet, or ReplicationController

Cluster Management Commands: #集羣管理相關命令
  certificate #證書   Modify certificate resources.
  cluster-info #集羣信息  Display cluster info
  top    #查看資源使用率        Display Resource (CPU/Memory/Storage) usage.
  cordon  #標記一個節點不可被調用       Mark node as unschedulable
  uncordon #標記一個節點可被調用      Mark node as schedulable
  drain  #排幹模式        Drain node in preparation for maintenance
  taint  #增長污點，給節點增長污點之後，能容忍該污點的pod才能被調度到該節點，默認master會有不少污點，因此建立的pod默認是不會在master上建立，這樣確保了master只運行各系統組件        Update the taints on one or more nodes

Troubleshooting and Debugging Commands: #修復和調試命令
  describe #描述一個資源的詳細信息      Show details of a specific resource or group of resources
  logs  #查看日誌         Print the logs for a container in a pod
  attach  #和docker 中的attach類似       Attach to a running container
  exec  #和docker exec 類似         Execute a command in a container
  port-forward #端口轉發  Forward one or more local ports to a pod
  proxy #代理         Run a proxy to the Kubernetes API server
  cp   #跨容器複製文件          Copy files and directories to and from containers.
  auth  #測試認證         Inspect authorization

Advanced Commands: #高級命令
  apply  #建立，修改        Apply a configuration to a resource by filename or stdin
  patch  #打補丁        Update field(s) of a resource using strategic merge patch
  replace #替換       Replace a resource by filename or stdin
  wait  #等待         Experimental: Wait for one condition on one or many resources
  convert #轉換       Convert config files between different API versions

Settings Commands:  #設置命令
  label   #打標籤       Update the labels on a resource
  annotate  #給資源加一個註解     Update the annotations on a resource
  completion #用來作命令補全    Output shell completion code for the specified shell (bash or zsh)

Other Commands: #其它命令
  alpha          Commands for features in alpha
  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         Runs a command-line plugin
  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).

　　二、查看kubectl 版本信息或集羣信息nginx

[root@k8smaster ~]# kubectl version
Client Version: version.Info{Major:"1", Minor:"11", GitVersion:"v1.11.1", GitCommit:"b1b29978270dc22fecc592ac55d903350454310a", GitTreeState:"clean", BuildDate:"2018-07-17T18:53:20Z", GoVer
sion:"go1.10.3", Compiler:"gc", Platform:"linux/amd64"}Server Version: version.Info{Major:"1", Minor:"11", GitVersion:"v1.11.1", GitCommit:"b1b29978270dc22fecc592ac55d903350454310a", GitTreeState:"clean", BuildDate:"2018-07-17T18:43:26Z", GoVer
sion:"go1.10.3", Compiler:"gc", Platform:"linux/amd64"}
[root@k8smaster ~]# kubectl cluster-info
Kubernetes master is running at https://192.168.10.10:6443
KubeDNS is running at https://192.168.10.10:6443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy

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

　　三、kubectl run 命令web

[root@k8smaster ~]# kubectl run --help
Create and run a particular image, possibly replicated. 

Creates a deployment or job to manage the created container(s).#基於這兩種中的某一種建立容器(也就是pod)

Examples:
  # Start a single instance of nginx.
  kubectl run nginx --image=nginx  #基於nginx鏡像啓動pod
  
  # Start a single instance of hazelcast and let the container expose port 5701 .
  kubectl run hazelcast --image=hazelcast --port=5701
  
  # Start a single instance of hazelcast and set environment variables "DNS_DOMAIN=cluster" and "POD_NAMESPACE=default"
in the container.
  kubectl run hazelcast --image=hazelcast --env="DNS_DOMAIN=cluster" --env="POD_NAMESPACE=default"
  
  # Start a single instance of hazelcast and set labels "app=hazelcast" and "env=prod" in the container.
  kubectl run hazelcast --image=nginx --labels="app=hazelcast,env=prod"
  
  # Start a replicated instance of nginx.
  kubectl run nginx --image=nginx --replicas=5 #啓動5個pod
  
  # Dry run. Print the corresponding API objects without creating them.
  kubectl run nginx --image=nginx --dry-run #單跑模式
  
  # Start a single instance of nginx, but overload the spec of the deployment with a partial set of values parsed from
JSON.
  kubectl run nginx --image=nginx --overrides='{ "apiVersion": "v1", "spec": { ... } }'
  
  # Start a pod of busybox and keep it in the foreground, don't restart it if it exits.
  kubectl run -i -t busybox --image=busybox --restart=Never #默認容器結束了會自動補上去，加了此命令後就不會再自動補上去
  
  # Start the nginx container using the default command, but use custom arguments (arg1 .. argN) for that command.
  kubectl run nginx --image=nginx -- <arg1> <arg2> ... <argN>
  
  # Start the nginx container using a different command and custom arguments.
  kubectl run nginx --image=nginx --command -- <cmd> <arg1> ... <argN> #加上自定義的命令
  
  # Start the perl container to compute π to 2000 places and print it out.
  kubectl run pi --image=perl --restart=OnFailure -- perl -Mbignum=bpi -wle 'print bpi(2000)'
  
  # Start the cron job to compute π to 2000 places and print it out every 5 minutes.
  kubectl run pi --schedule="0/5 * * * ?" --image=perl --restart=OnFailure -- perl -Mbignum=bpi -wle 'print bpi(2000)' #建立一個定時job

　　　　使用kubectl run建立一個單跑模式的nginx容器docker

[root@k8smaster ~]# kubectl run nginx-deploy --image=nginx:1.14-alpine --port=80 --replicas=1 --dry-run=true
deployment.apps/nginx-deploy created (dry run) #deployment控制器下所控制的應用程序，叫作nginx-deploy

　　　　使用kubectl run建立一個nginx容器shell

[root@k8smaster ~]# kubectl run nginx-deploy --image=nginx:1.14-alpine --port=80 --replicas=1
deployment.apps/nginx-deploy created
[root@k8smaster ~]# kubectl get deployment
NAME           DESIRED(指望)   CURRENT(當前)   UP-TO-DATE   AVAILABLE（可用）   AGE
nginx-deploy   1         1         1            0           23s

　　　　過一下子查看顯示已經可用api

[root@k8smaster ~]# kubectl get deployment
NAME           DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
nginx-deploy   1         1         1            1           2m

　　　　查看建立的podbash

[root@k8smaster ~]# kubectl get pods
NAME                          READY     STATUS    RESTARTS   AGE
nginx-deploy-5b595999-vw5vt   1/1       Running   0          3m
[root@k8smaster ~]# kubectl get pods -o wide
NAME                          READY     STATUS    RESTARTS   AGE       IP           NODE
nginx-deploy-5b595999-vw5vt   1/1       Running   0          4m        10.244.2.2   k8snode2

　　　　到節點2中查看網橋可用發現啓動的相應pod是鏈接在cni0 網橋上的session

[root@k8snode2 ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:b3:80:ea brd ff:ff:ff:ff:ff:ff
    inet 192.168.10.12/24 brd 192.168.10.255 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::df7a:6e6c:357:ba25/64 scope link 
       valid_lft forever preferred_lft forever
3: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN 
    link/ether 02:42:85:22:4d:73 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
       valid_lft forever preferred_lft forever
4: flannel.1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc noqueue state UNKNOWN 
    link/ether 92:d1:5f:6c:71:7b brd ff:ff:ff:ff:ff:ff
    inet 10.244.2.0/32 scope global flannel.1
       valid_lft forever preferred_lft forever
    inet6 fe80::90d1:5fff:fe6c:717b/64 scope link 
       valid_lft forever preferred_lft forever
5: cni0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc noqueue state UP qlen 1000
    link/ether 0a:58:0a:f4:02:01 brd ff:ff:ff:ff:ff:ff
    inet 10.244.2.1/24 scope global cni0
       valid_lft forever preferred_lft forever
    inet6 fe80::6429:a3ff:fe46:ac7e/64 scope link 
       valid_lft forever preferred_lft forever
6: vethadaa4f42@if3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1450 qdisc noqueue master cni0 state UP 
    link/ether 3e:4d:5f:db:62:17 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet6 fe80::3c4d:5fff:fedb:6217/64 scope link 
       valid_lft forever preferred_lft forever
[root@k8snode2 ~]# docker exec -it 706159bf29fc /bin/sh
/ # ifconfig 
eth0      Link encap:Ethernet  HWaddr 0A:58:0A:F4:02:02  
          inet addr:10.244.2.2  Bcast:0.0.0.0  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1450  Metric:1
          RX packets:15 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:1206 (1.1 KiB)  TX bytes:0 (0.0 B)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:65536  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1 
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

/ #

[root@k8snode2 ~]# curl 10.244.2.2
<!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>
[root@k8snode2 ~]#

　　四、kubelet delete ：使用此命令刪除剛剛建立的nginx容器，會發現刪除後控制器會再次啓動一個pod

[root@k8smaster ~]# kubectl delete pods nginx-deploy-5b595999-vw5vt
pod "nginx-deploy-5b595999-vw5vt" deleted
[root@k8smaster ~]# kubectl get pods -o wide
NAME                          READY     STATUS              RESTARTS   AGE       IP        NODE
nginx-deploy-5b595999-kbj6j   0/1       ContainerCreating   0          17s       <none>    k8snode1
[root@k8smaster ~]# kubectl get pods -o wide
NAME                          READY     STATUS    RESTARTS   AGE       IP           NODE
nginx-deploy-5b595999-kbj6j   1/1       Running   0          2m        10.244.1.2   k8snode1

　　五、kubelet expose （暴露）:此時會發現pod的ip已經變了，所以咱們須要建立一個固定的service來提供固定的訪問接口。咱們使用kubelet expose命令來進行建立。(service 默認只服務於集羣的內部pod客戶端)

[root@k8smaster ~]# kubectl expose deployment(控制器) nginx-deploy（控制器名字） --name=nginx  --port=80(service 端口) --target-port=80(pod端口) --protocol=TCP
service/nginx exposed

　　　　查看和測試建立後的service

[root@k8smaster ~]# kubectl get service
NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP   20h
nginx        ClusterIP   10.103.127.92   <none>        80/TCP    17m

[root@k8smaster ~]# kubectl describe service nginx
Name:              nginx
Namespace:         default
Labels:            run=nginx-deploy
Annotations:       <none>
Selector:          run=nginx-deploy
Type:              ClusterIP
IP:                10.103.127.92
Port:              <unset>  80/TCP
TargetPort:        80/TCP
Endpoints:         10.244.1.2:80
Session Affinity:  None
Events:            <none>
[root@k8smaster ~]# curl 10.103.127.92
<!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>
[root@k8smaster ~]#

　　　　刪除pod而後等自動重建後繼續訪問原來的service發現依然能夠訪問

[root@k8smaster ~]# kubectl get pods -o wide
NAME                          READY     STATUS    RESTARTS   AGE       IP           NODE
client                        0/1       Error     0          14m       10.244.2.3   k8snode2
nginx-deploy-5b595999-jdbtn   1/1       Running   0          31s       10.244.1.3   k8snode1
[root@k8smaster ~]# kubectl delete pods nginx-deploy-5b595999-jdbtn
pod "nginx-deploy-5b595999-jdbtn" deleted
[root@k8smaster ~]# kubectl get pods -o wide
NAME                          READY     STATUS    RESTARTS   AGE       IP           NODE
client                        0/1       Error     0          14m       10.244.2.3   k8snode2
nginx-deploy-5b595999-d9lv5   1/1       Running   0          27s       10.244.2.4   k8snode2
[root@k8smaster ~]# kubectl get service
NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP   21h
nginx        ClusterIP   10.103.127.92   <none>        80/TCP    42m
[root@k8smaster ~]# curl 10.103.127.92
<!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>

　　六、關於集羣dns,全部啓動的pod的nameserver 地址都是指向集羣中系統名稱空間中的dns的service的

[root@k8smaster ~]# kubectl get svc --all-namespaces
NAMESPACE     NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)         AGE
default       kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP         21h
default       nginx        ClusterIP   10.103.127.92   <none>        80/TCP          29m
kube-system   kube-dns     ClusterIP   10.96.0.10      <none>        53/UDP,53/TCP   21h
[root@k8smaster ~]# kubectl describe svc kube-dns -n kube-system 
Name:              kube-dns
Namespace:         kube-system
Labels:            k8s-app=kube-dns
                   kubernetes.io/cluster-service=true
                   kubernetes.io/name=KubeDNS
Annotations:       prometheus.io/port=9153
                   prometheus.io/scrape=true
Selector:          k8s-app=kube-dns
Type:              ClusterIP
IP:                10.96.0.10
Port:              dns  53/UDP
TargetPort:        53/UDP
Endpoints:         10.244.0.2:53,10.244.0.3:53
Port:              dns-tcp  53/TCP
TargetPort:        53/TCP
Endpoints:         10.244.0.2:53,10.244.0.3:53
Session Affinity:  None
Events:            <none>
[root@k8smaster ~]# kubectl run client --image=busybox --replicas=1 --replicas=1 -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:5

　　七、get pod時查看label(service 與pod 之間是經過label關聯的)

[root@k8smaster ~]# kubectl get pods --show-labels -o wide
NAME                          READY     STATUS    RESTARTS   AGE       IP           NODE       LABELS
nginx-deploy-5b595999-d9lv5   1/1       Running   0          15m       10.244.2.4   k8snode2   pod-template-hash=16151555,run=nginx-deploy

　　八、kubectl edit #能夠編輯運行的service，不過當前版本應該只能夠查看不支持編輯

[root@k8smaster ~]# kubectl edit svc nginx
Edit cancelled, no changes made.

　　九、svc還有負載均衡的功能

[root@k8smaster ~]# kubectl run myapp --image=ikubernetes/myapp:v1 --replicas=2
deployment.apps/myapp created
[root@k8smaster ~]# kubectl get pods
NAME                          READY     STATUS    RESTARTS   AGE
myapp-848b5b879b-5hg7h        1/1       Running   0          2m
myapp-848b5b879b-ptqjd        1/1       Running   0          2m
nginx-deploy-5b595999-d9lv5   1/1       Running   0          56m
[root@k8smaster ~]# kubectl get pods -o wide
NAME                          READY     STATUS    RESTARTS   AGE       IP           NODE
myapp-848b5b879b-5hg7h        1/1       Running   0          3m        10.244.2.5   k8snode2
myapp-848b5b879b-ptqjd        1/1       Running   0          3m        10.244.1.4   k8snode1
nginx-deploy-5b595999-d9lv5   1/1       Running   0          57m       10.244.2.4   k8snode2

^C[root@k8smaster ~]# kubectl get deployment -o wide -w #持續監控
NAME           DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE       CONTAINERS     IMAGES                 SELECTOR
myapp          2         2         2            2           4m        myapp          ikubernetes/myapp:v1   run=myapp
nginx-deploy   1         1         1            1           4h        nginx-deploy   nginx:1.14-alpine      run=nginx-deploy

　　　　建立svc並查看轉發狀況

[root@k8smaster ~]# kubectl expose deployment myapp --name=myapp --port=80
service/myapp exposed

[root@k8smaster ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.96.0.1        <none>        443/TCP   22h
myapp        ClusterIP   10.106.171.207   <none>        80/TCP    12s
nginx        ClusterIP   10.103.127.92    <none>        80/TCP    1h
[root@k8smaster ~]# kubectl describe svc myapp
Name:              myapp
Namespace:         default
Labels:            run=myapp
Annotations:       <none>
Selector:          run=myapp
Type:              ClusterIP
IP:                10.106.171.207
Port:              <unset>  80/TCP
TargetPort:        80/TCP
Endpoints:         10.244.1.4:80,10.244.2.5:80
Session Affinity:  None
Events:            <none>
[root@k8smaster ~]# curl 10.106.171.207/hostname.html
myapp-848b5b879b-ptqjd
[root@k8smaster ~]# curl 10.106.171.207/hostname.html
myapp-848b5b879b-ptqjd
[root@k8smaster ~]# curl 10.106.171.207/hostname.html
myapp-848b5b879b-ptqjd
[root@k8smaster ~]# curl 10.106.171.207/hostname.html
myapp-848b5b879b-ptqjd
[root@k8smaster ~]# curl 10.106.171.207/hostname.html
myapp-848b5b879b-ptqjd
[root@k8smaster ~]# curl 10.106.171.207/hostname.html
myapp-848b5b879b-ptqjd
[root@k8smaster ~]# curl 10.106.171.207/hostname.html
myapp-848b5b879b-5hg7h
[root@k8smaster ~]# curl 10.106.171.207/hostname.html
myapp-848b5b879b-5hg7h
[root@k8smaster ~]# curl 10.106.171.207/hostname.html
myapp-848b5b879b-5hg7h
[root@k8smaster ~]# curl 10.106.171.207/hostname.html
myapp-848b5b879b-5hg7h
[root@k8smaster ~]# curl 10.106.171.207/hostname.html

　　十、kubectl scale #動態改變副本數

[root@k8smaster ~]# kubectl scale --replicas=5 deployment myapp
deployment.extensions/myapp scaled
[root@k8smaster ~]# kubectl get pods
NAME                          READY     STATUS    RESTARTS   AGE
myapp-848b5b879b-5hg7h        1/1       Running   0          22m
myapp-848b5b879b-6fvr5        1/1       Running   0          30s
myapp-848b5b879b-dpwpj        1/1       Running   0          30s
myapp-848b5b879b-f77xt        1/1       Running   0          30s
myapp-848b5b879b-ptqjd        1/1       Running   0          22m
nginx-deploy-5b595999-d9lv5   1/1       Running   0          1h

[root@k8smaster ~]# while true; do curl 10.106.171.207/hostname.html;sleep 1; done
myapp-848b5b879b-ptqjd
myapp-848b5b879b-5hg7h
myapp-848b5b879b-dpwpj
myapp-848b5b879b-6fvr5
myapp-848b5b879b-dpwpj
myapp-848b5b879b-f77xt
myapp-848b5b879b-dpwpj
myapp-848b5b879b-5hg7h
myapp-848b5b879b-dpwpj
myapp-848b5b879b-f77xt
myapp-848b5b879b-dpwpj
^C
[root@k8smaster ~]# kubectl scale --replicas=3 deployment myapp
deployment.extensions/myapp scaled
[root@k8smaster ~]# kubectl get pods
NAME                          READY     STATUS    RESTARTS   AGE
myapp-848b5b879b-5hg7h        1/1       Running   0          25m
myapp-848b5b879b-dpwpj        1/1       Running   0          3m
myapp-848b5b879b-ptqjd        1/1       Running   0          25m
nginx-deploy-5b595999-d9lv5   1/1       Running   0          1h
[root@k8smaster ~]# while true; do curl 10.106.171.207/hostname.html;sleep 1; done
myapp-848b5b879b-ptqjd
myapp-848b5b879b-dpwpj
myapp-848b5b879b-ptqjd
myapp-848b5b879b-5hg7h
myapp-848b5b879b-ptqjd
^C

　　十一、kubelet set image 滾動升級更新

　　　　先查看各pod以及其鏡像，而後滾動更新後發現pod名稱和鏡像都發生了改變

[root@k8smaster ~]# kubectl get pods
NAME                          READY     STATUS    RESTARTS   AGE
myapp-848b5b879b-5hg7h        1/1       Running   0          30m
myapp-848b5b879b-dpwpj        1/1       Running   0          8m
myapp-848b5b879b-ptqjd        1/1       Running   0          30m
nginx-deploy-5b595999-d9lv5   1/1       Running   0          1h
[root@k8smaster ~]# kubectl describe myapp-848b5b879b-5hg7h
error: the server doesn't have a resource type "myapp-848b5b879b-5hg7h"
[root@k8smaster ~]# kubectl describe pod myapp-848b5b879b-5hg7h
Name:               myapp-848b5b879b-5hg7h
Namespace:          default
Priority:           0
PriorityClassName:  <none>
Node:               k8snode2/192.168.10.12
Start Time:         Wed, 08 May 2019 22:41:52 +0800
Labels:             pod-template-hash=4046164356
                    run=myapp
Annotations:        <none>
Status:             Running
IP:                 10.244.2.5
Controlled By:      ReplicaSet/myapp-848b5b879b
Containers:
  myapp:
    Container ID:   docker://54587de57edd701951f1e0492504a17be62c9fa18002f5bfc58b252ed536b029
    Image:          ikubernetes/myapp:v1
    Image ID:       docker-pullable://ikubernetes/myapp@sha256:9c3dc30b5219788b2b8a4b065f548b922a34479577befb54b03330999d30d513
    Port:           <none>
    Host Port:      <none>
    State:          Running
      Started:      Wed, 08 May 2019 22:42:45 +0800
    Ready:          True
    Restart Count:  0
    Environment:    <none>
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from default-token-jvtl7 (ro)
Conditions:
  Type              Status
  Initialized       True 
  Ready             True 
  ContainersReady   True 
  PodScheduled      True 
Volumes:
  default-token-jvtl7:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  default-token-jvtl7
    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:
  Type    Reason     Age   From               Message
  ----    ------     ----  ----               -------
  Normal  Pulling    18h   kubelet, k8snode2  pulling image "ikubernetes/myapp:v1"
  Normal  Pulled     18h   kubelet, k8snode2  Successfully pulled image "ikubernetes/myapp:v1"
  Normal  Created    18h   kubelet, k8snode2  Created container
  Normal  Started    18h   kubelet, k8snode2  Started container
  Normal  Scheduled  30m   default-scheduler  Successfully assigned default/myapp-848b5b879b-5hg7h to k8snode2
[root@k8smaster ~]# kubectl set image deployment myapp myapp=ikubernetes/myapp:v2
deployment.extensions/myapp image updated
[root@k8smaster ~]# kubectl rollout status deployment myapp #查看滾動更新狀態
deployment "myapp" successfully rolled out
[root@k8smaster ~]# kubectl get pods
NAME                          READY     STATUS    RESTARTS   AGE
myapp-74c94dcb8c-ccqzs        1/1       Running   0          2m
myapp-74c94dcb8c-jmj4p        1/1       Running   0          2m
myapp-74c94dcb8c-lc2n6        1/1       Running   0          2m
nginx-deploy-5b595999-d9lv5   1/1       Running   0          1h

　　　　另啓動一個shell 訪問鏡像，能夠看到動態更新效果

[root@k8smaster ~]# while true; do curl 10.106.171.207;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: 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>
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>
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>
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>
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: 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: 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>
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>

　　十二、kubectl rollout #版本回退（回滾）

[root@k8smaster ~]# curl 10.106.171.207
Hello MyApp | Version: v2 | <a href="hostname.html">Pod Name</a>
[root@k8smaster ~]# kubectl get pods
NAME                          READY     STATUS    RESTARTS   AGE
myapp-74c94dcb8c-8l4n7        1/1       Running   0          11s
myapp-74c94dcb8c-dzlfx        1/1       Running   0          14s
myapp-74c94dcb8c-tsd2s        1/1       Running   0          12s
nginx-deploy-5b595999-d9lv5   1/1       Running   0          1h
[root@k8smaster ~]# kubectl rollout undo deployment myapp #不加鏡像版本默認回退到上一個版本
deployment.extensions/myapp
[root@k8smaster ~]# kubectl get pods
NAME                          READY     STATUS        RESTARTS   AGE
myapp-74c94dcb8c-8l4n7        0/1       Terminating   0          22s
myapp-74c94dcb8c-dzlfx        1/1       Terminating   0          25s
myapp-74c94dcb8c-tsd2s        0/1       Terminating   0          23s
myapp-848b5b879b-5k4s4        1/1       Running       0          5s
myapp-848b5b879b-bzblz        1/1       Running       0          3s
myapp-848b5b879b-hzbf5        1/1       Running       0          2s
nginx-deploy-5b595999-d9lv5   1/1       Running       0          1h

[root@k8smaster ~]# kubectl get pods
NAME                          READY     STATUS    RESTARTS   AGE
myapp-848b5b879b-5k4s4        1/1       Running   0          13s
myapp-848b5b879b-bzblz        1/1       Running   0          11s
myapp-848b5b879b-hzbf5        1/1       Running   0          10s
nginx-deploy-5b595999-d9lv5   1/1       Running   0          1h
[root@k8smaster ~]# curl 10.106.171.207
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

　　　　還能夠自動擴縮容，不過須要和資源監控配合。

　　1三、能夠經過iptables -vnL查看iptables規則，能夠看到service是出如今其中的。　　

　　1四、經過修改svc 的type屬性爲NodePort 能夠在外部訪問到對應的pod 服務

[root@k8smaster ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.96.0.1        <none>        443/TCP   23h
myapp        ClusterIP   10.106.171.207   <none>        80/TCP    50m
nginx        ClusterIP   10.103.127.92    <none>        80/TCP    2h
[root@k8smaster ~]# kubectl edit svc myapp 
service/myapp edited

#打開後內容以下
# 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: 2019-05-09T08:28:47Z
  labels:
    run: myapp
  name: myapp
  namespace: default
  resourceVersion: "49560"
  selfLink: /api/v1/namespaces/default/services/myapp
  uid: 776ef2c3-7234-11e9-be24-000c29d142be
spec:
  clusterIP: 10.106.171.207
  externalTrafficPolicy: Cluster
  ports:
  - nodePort: 30935
    port: 80
    protocol: TCP
    targetPort: 80
  selector:
    run: myapp
  sessionAffinity: None
  type: NodePort #此處由ClusterIP改成NodePort
status:
  loadBalancer: {}


[root@k8smaster ~]# kubectl get svc
NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)        AGE
kubernetes   ClusterIP   10.96.0.1        <none>        443/TCP        23h
myapp        NodePort    10.106.171.207   <none>        80:30935/TCP   51m
nginx        ClusterIP   10.103.127.92    <none>        80/TCP         2h
[root@k8smaster ~]# curl 192.168.10.10:30935
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>

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