kubectl

Table of Contents

kubectl

kubectl

Kubernetes API Server最常用的客户端程序之一，功能强大，能够几乎完成除了安装部署之外的所有管理操作

连接API Server 对K8s相关对象资源的增删改查

syntax

kubectl [command] [TYPE] [NAME] [flags]

installation

mac osx

binary

Download the latest release:

curl -LO https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/darwin/amd64/kubectl

Make the kubectl binary executable.

chmod +x ./kubectl

Move the binary in to your PATH.

sudo mv ./kubectl /usr/local/bin/kubectl

brew

brew install kubernetes-cli

基础命令

create 创建资源

通过文件或标准输入创建资源

kubectl create -f nignx-deploy.yaml -f nginx-svc.yaml

delete 删除

基于文件名，stdin，资源或名字，以及资源和选择器删除资源

删除默认名称空间中ngnix-svc的Service 资源对象

kubectl delete services nginx-svc

删除默认名称空间中所有的Deployment控制器

kubectl delete deployment --all

--all

删除kube-public 名称空间中的所有pod对象

kubectl delete pods --all -n kube-public

删除所有名称空间的所有资源

kubectl delete all --all

-f 指定配置

kubectl delete -f pod-example.yaml

--grace-period

默认删除操作为30s，使用此参数自定义其时常

若使用0表示直接强制删除指定的资源，需同时使用--force 选项

edit 编辑资源

explain 资源文档

获取相关帮助

解释Pod资源的一级字段

kubectl explain pods

某对象下的二级字段, 三四级依此类推

kubectl explain pods.spec

expose 暴露服务

基于rc，service，deployment或pod创建Service资源

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]

--port指service 端口，一般使用众所周知的端口

--target-port指pod端口

两个端口可以一样

[root@master ~]# kubectl expose deployment nginx-deploy --name=nginx --port=80 --target-port=80 --protocol=TCP
service/nginx exposed
[root@master ~]# kubectl get service
NAME         TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.96.0.1      <none>        443/TCP   3h34m
nginx        ClusterIP   10.96.216.63   <none>        80/TCP    10s

10.96.216.63 service对外地址，代理后端pod

get 显示资源

即从Kubernetes里面获取指定的API对象

controllerrevision 记录Controller版本

用于记录某种Controller对象的版本

$ kubectl get controllerrevision -n kube-system -l name=fluentd-elasticsearch
NAME                               CONTROLLER                             REVISION   AGE
fluentd-elasticsearch-64dc6799c9   daemonset.apps/fluentd-elasticsearch   2          1h

查看fluentd-elasticsearch对应的ControllerRevision

列出所有资源

kubectl get namespaces

查看多个资源

kubectl get pods,services -o wide

-l 标签选择器

列出名称空间中拥有k8s-app标签名称的所有Pod 对象

kubectl get pods -l k8s-app -n kube-system

等值关系

=, !=, ==

集合关系

KEY in (VALUE1, VALUE2,...)

KEY notin (VALUE1, VALUE2,...)

!KEY

-L 标签列表

显示每一个对象的标签值

kubectl get pods -l 'env in (production,dev),!tier' -L env,tier

-o 输出

yaml

kubectl get pods -l component=kube=apiserver -o yaml -n kube-system

json

wide 额外信息

显示资源的额外信息

kubectl get pods -o wide

name 名称

仅仅打印资源名称

go-template go 模版

以自定义的go模版格式化输出API对象信息

custom-columns 自定义输出

自定义要输出的字段

nodes

查看键名为SSD标签的node资源

kubectl get nodes -l 'disktype' -L disktype

run 运行

通过创建Deployment在集群中运行指定的镜像

kubectl run nginx-deploy --image=nginx:1.12 --replicas=2

set 设置属性

设置指定资源的特定属性

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-deploy
  namespace: default
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
      release: canary
  template:
    metadata:
      labels:
        app: myapp
        release: canary
    spec:
      containers:
      - name: myapp
        image: ikubernetes/myapp:v1
        ports:
        - name: http
          containerPort: 80

# kubectl set image deployment myapp-deploy myapp=ikubernetes/myapp:v3 && kubectl rollout pause deployment myapp-deploy
deployment.apps/myapp-deploy image updated
deployment.apps/myapp-deploy paused

image

Deployment对应用进行版本控制

$ kubectl image deployment/nginx-deployment nginx=nginx:1.91
deployment.extensions/nginx-deployment image updated

这里的nginx:1.91 是错误的版本

部署命令

autoscale 自动伸缩

对Deployment，ReplicaSet或RC进行自动伸缩

scale 扩容/缩容

kubectl scale deployments/myapp --replicas=3

replicas 指明对象创建或管理Pod对象的副本数量

kubectl scale deployments/myapp --replicas=2

[root@master ~]# kubectl scale --replicas=5 deployment myapp
deployment.extensions/myapp scaled
[root@master ~]# kubectl scale --replicas=1 deployment myapp
deployment.extensions/myapp scaled

rollout 滚动更新

管理资源的滚动更新

history

查看Deployment 变更的对应版本

$ kubectl rollout history deployment/nginx-deployment
deployments "nginx-deployment"
REVISION    CHANGE-CAUSE
1           kubectl create -f nginx-deployment.yaml --record
2           kubectl edit deployment/nginx-deployment
3           kubectl set image deployment/nginx-deployment nginx=nginx:1.91

pause

由于Deployment进行的每一次更新操作，都会生成一个新的ReplicaSet对象，为此，可以指定多次更新操作之后，只生成一个ReplicaSet

即在更新Deployment之前，执行下列操作

$ kubectl rollout pause deployment/nginx-deployment
deployment.extensions/nginx-deployment paused

Deployment将处于暂停状态，这样对Deployment的所有修改，都不会出发滚动更新

resume

恢复Deployment 滚动更新

[root@master ~]# kubectl rollout resume deployment myapp-deployment
deployment.extensions/myapp-deployment resumed

可以看到更新状况

[root@master ~]# kubectl rollout status deployment myapp-deployment
Waiting for deployment "myapp-deployment" rollout to finish: 1 out of 5 new replicas have been updated...
Waiting for deployment spec update to be observed...
Waiting for deployment spec update to be observed...
Waiting for deployment "myapp-deployment" rollout to finish: 1 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deployment" rollout to finish: 1 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deployment" rollout to finish: 2 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deployment" rollout to finish: 2 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deployment" rollout to finish: 2 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deployment" rollout to finish: 3 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deployment" rollout to finish: 3 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deployment" rollout to finish: 4 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deployment" rollout to finish: 4 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deployment" rollout to finish: 4 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deployment" rollout to finish: 4 out of 5 new replicas have been updated...
Waiting for deployment "myapp-deployment" rollout to finish: 1 old replicas are pending termination...
Waiting for deployment "myapp-deployment" rollout to finish: 1 old replicas are pending termination...
deployment "myapp-deployment" successfully rolled out

status

监听更新状态

[root@master ~]# kubectl rollout status deployment myapp-deployment
Waiting for deployment "myapp-deployment" rollout to finish: 1 out of 5 new replicas have been updated...

undo

撤销滚动版本, 默认为上一个版本

$ kubectl rollout undo deployment/nginx-deployment --to-revision=2
deployment.extensions/nginx-deployment

这里指定了滚动的版本号2

[root@master ~]# kubectl rollout history deployment myapp-deployment
deployment.extensions/myapp-deployment
REVISION  CHANGE-CAUSE
1         <none>
2         <none>
3         <none>

[root@master ~]# kubectl rollout undo deployment myapp-deployment --to-revision=1
deployment.extensions/myapp-deployment rolled back
[root@master ~]#
[root@master ~]# kubectl rollout history deployment myapp-deployment
deployment.extensions/myapp-deployment
REVISION  CHANGE-CAUSE
2         <none>
3         <none>
4         <none>

这里的4 表示revision号码变动了

rolling-update 滚动升级

对ReplicationController执行滚动升级

集群管理

certificate 数字证书

配置数字证书资源

cluster-info 集群信息

打印集群信息

cordon 不可用状态

指定node 设定为不可用（unschedulable）状态

drain 维护模式

值得node的负载以进入维护模式

移除worker node

kubectl drain swarm1 --delete-local-data --force --ignore-daemonsets

kubectl delete node swarm1

top 使用率

打印资源（cpu/memory/storage）使用率

taint 声明污点

为node声明污点及标准行为

uncordon 可用状态

指定node 设定为可用（schedulable）状态

排错调试

attach 附加终端

附加终端至一个运行中的容器

apiVersion: v1
kind: Pod
metadata:
  name: nginx
spec:
  shareProcessNamespace: true
  containers:
  - name: nginx
    image: nginx
  - name: shell
    image: busybox
    stdin: true
    tty: true

kubectl attach -it nginx -c shell

auth 授权信息

打印授权信息

cp 复制

在容器间复制文件或者目录

exec 执行命令

容器内执行命令

kubectl exec kube-apiserver-master.xuxuehua.com -n kube-system --ps

Pod对象中的容器里面运行ps命令

-it 交互Shell

kubectl exec -it $POD_NAME /bin/sh

describe 详细信息

kubectl describe (-f FILENAME | TYPE [NAME_PREFIX | -l label] | TYPE/NAME)

pod

指定pod查看一个API对象的细节

显示指定的资源或者资源组的详细信息

kubectl describe pods -l component=kube-apiserver -n kube-system

kubectl describe services myapp-svc

service/svc

查看service 对象

[root@master ~]# kubectl describe svc nginx
Name:              nginx
Namespace:         default
Labels:            run=nginx-deploy
Annotations:       <none>
Selector:          run=nginx-deploy
Type:              ClusterIP
IP:                10.96.216.63
Port:              <unset>  80/TCP
TargetPort:        80/TCP
Endpoints:         10.244.2.2:80
Session Affinity:  None
Events:            <none>

这里指定了pod标签，因此才可以查看到对应的信息

[root@master ~]# kubectl get pods --show-labels
NAME                           READY   STATUS    RESTARTS   AGE   LABELS
client                         0/1     Error     0          19m   run=client
nginx-deploy-55d8d67cf-7zkxm   1/1     Running   0          9h    pod-template-hash=55d8d67cf,run=nginx-deploy

log/logs 日志

pod内某容器的日志

kubectl log [-f] [-p] (POD|TYPE/NAME) [-c CONTAINER] [options]

-f 类似于tail -f

kubectl logs kube-apiserver-master.xuxuehua.com -n kube-system

-c 指定容器名称

port-forward 端口转发

将本地的一个或着多个端口转发至指定的pod

proxy API Server代理

能够访问Kubernetes API Server的代理

高级命令

apply 实现声明

既可以创建，也可以更新

基于文件或者stdin 将配置应用于资源

kubectl apply -f nginx-deploy.yaml -f nginx-svc.yaml

convert API转换

为不通的API版本转换配置文件

patch 补丁更新

使用策略合并补丁更新资源字段

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp-deploy
  namespace: default
spec:
  replicas: 3
  selector:
    matchLabels:
      app: myapp
      release: canary
  template:
    metadata:
      labels:
        app: myapp
        release: canary
    spec:
      containers:
      - name: myapp
        image: ikubernetes/myapp:v1
        ports:
        - name: http
          containerPort: 80

# kubectl patch deployment myapp-deploy -p '{"spec":{"strategy":{"rollingUpdate":{"maxSurge":1,"maxUnavailable":0}}}}'
deployment.apps/myapp-deploy patched

replace 替换资源

基于文件或者stdin替换一个资源

设置命令

annotate 资源注释

添加资源注释

kubectl annotate pods pod-example ilinux.io/created-by="cluster admin"

查看注解

kubectl describe pods pod-example | grep "Annotations"

completion 补全码

输出指定的shell （bash）的补全码

g 资源标签

更新指定资源标签

kubectl label [--overwrite] (-f FILENAME | TYPE NAME) KEY_1=VAL_1 ... KEY_N=VAL_N
[--resource-version=version] [options]

添加标签

为pod-example 添加env=production 标签

kubectl label pods/pod-example env=production

[root@master ~]# kubectl label pods pod-demo release=canary
pod/pod-demo labeled
[root@master ~]# kubectl get pods -l app --show-labels
NAME       READY   STATUS    RESTARTS   AGE     LABELS
pod-demo   2/2     Running   0          6m17s   app=myapp,release=canary,tier=frontend

覆盖标签 --overwrite

[root@master ~]# kubectl label pods pod-demo release=canary
pod/pod-demo labeled
[root@master ~]# kubectl get pods -l app --show-labels
NAME       READY   STATUS    RESTARTS   AGE     LABELS
pod-demo   2/2     Running   0          6m17s   app=myapp,release=canary,tier=frontend
[root@master ~]# kubectl label pods pod-demo release=stable --overwrite
pod/pod-demo labeled
[root@master ~]# kubectl get pods -l app --show-labels
NAME       READY   STATUS    RESTARTS   AGE     LABELS
pod-demo   2/2     Running   0          7m13s   app=myapp,release=stable,tier=frontend

nodes

设置标签以及标识

kubectl label nodes node01.xurick.com disktype=ssd

查看键名为SSD标签的node资源

kubectl get nodes -l 'disktype' -L disktype

其他命令

api-versions API版本信息

以group/version格式打印服务器支持的API版本信息

config 配置内容

配置kubeconfig文件的内容

help 帮助

打印任意命令的帮助信息

option 通用选项

-s / --server 指定API Server

指定API Server的地址和端口

--kubeconfig 文件路径

是用kubeconfig 文件路径，默认为~/.kube/config

--namespace 名称空间

命令执行的目标名称空间

plugin 命令行插件

运行命令行插件

version 版本信息

打印Kubernetes的服务器端和客户端版本信息