kubectl是目前管理k8s集群的最强利器.所有对集群的控制和管理都可以通个kubectl进行.

通过kubectl --help查看帮助信息。

基本命令(初级):

create 创建一个新的资源从一个文件或者stdin

expose 获取replication controller,service,deployment和pod,并将其作为一个新的服务.

run 在集群内运行特定镜像.

set 在对象上设置特定功能

run-container 在集群上运行特定镜像,已被run替代

基本命令(中级):

get 现实一个或多个资源

explain 资源文档

edit 编辑服务器上的资源

delete 按照文件名称,标准输入,资源和名称来刪除资源,还可以通过资源和标签选择器

部署命令:

rollout 管理资源的部署

rolling-update 执行给定的ReplicationController的滚动更新

scale 为Deployment,ReplicaSet,Replication等控制器设置一个新的大小或者任务

autoscale 自动扩展 Deployment, ReplicaSet, 或 ReplicationController

集群管理命令:

certificate 修改证书资源

cluster-info显示集群信息

top 显示资源 (CPU/Memory/Storage)使用情况

cordon 将节点标记为不可调度

uncordon 将节点标记为可调度

drain 节点准备维护

taint 更新一个或多个节点上的错误

故障排除与调试命令:

describe 显示特定资源或资源组的详细信息

logs 打印pod中容器的日志

attach 进入正在运行的容器

exec 在容器中执行命令

port-forward 将一个或多个本地端口转发到pod

proxy 运行代理到kubernetes的API Servercp从容器中复制一个文件或者目录

auth 检查授权

高级命令:

apply 通过filename或stdin将配置应用到资源patch更新资源的字段,通过策略合并

replace 用filename或stdin替换资源

convert 在不同的API版本之间转换配置文件

配置命令:

label 为资源更新标签

annotate 为资源更新注释

completion 输出指定shell的shell代码(bash or zsh)

其它命令:

api-versions 输出服务器支持的API版本

config 修改kubeconfig配置文件

help 查看帮助信息

plugin 运行命令行插件

version 打印客户端和服务端的版本信息

当然也可以通过   kubectl config --help类似命令查看子命令：

修改kubeconfig文件中的数据.

The loading order follows these rules:1. If the --kubeconfig flag is set, then only that fileis loaded. The flag

may only be set once and no merging takes place.2. If $KUBECONFIG environment variable is set, thenit is used a list of paths

(normal path delimitting rulesforyour system). These paths are merged. When

a value is modified, it is modifiedin the filethat defines the stanza. When a

value is created, it is createdin the first file that exists. If no files inthe chain exist,then it creates the last file inthe list.3. Otherwise, ${HOME}/.kube/config is used and no merging takes place.

可用命令:

current-context 显示当前contexts

delete-cluster 从kubeconfig中刪除指定的集群

delete-context 从kubeconfig中刪除指定的上下文

get-clusters 显示kubeconfig中定义的集群

get-contexts 描述一个或多个contexts

rename-context 在kubeconfig中给一个context改名

set 在kubeconfig中设置单个值

set-cluster 在kubeconfig中设置一个集群

set-context 在kubeconfig中设置一个context

set-credentials 在kubeconfig中设置一个用户

unset 取消设置

use-context 在kubeconfig中设置current-context

view 显示合并后的kubeconfig设置或指定kubeconfig文件

kubectl的命令可以分为三类：

1.集群访问配置：kubectl config

配置kubectl管理的kubernetes集群的配置信息,与Linux中的命令行不同的是,命令行的设置直接操控文件.

(1)kubectl config view:查看当前节点的kubeconfig配置信息.

kubernetes可以有多个集群，一个集群又可以配置无数过service，多层级有利于梳理计算机资源。

打印文件的内容,密钥数据省略.

root@VM-16-6-ubuntu:~# cat /etc/kubernetes/admin.conf

apiVersion: v1

clusters:-cluster:

certificate-authority-data: ...

server: https://148.70.251.10:6443

name: kubernetes

contexts:-context:

cluster: kubernetes

user: kubernetes-admin

name: kubernetes-admin@kubernetes

current-context: kubernetes-admin@kubernetes

kind: Config

preferences: {}

users:- name: kubernetes-admin

user:

client-certificate-data: ...

client-key-data: ...

通过kubectl config view可以查看的相同的信息.

root@VM-16-6-ubuntu:~# kubectl config view

apiVersion: v1

clusters:-cluster:

certificate-authority-data: REDACTED

server: https://148.70.251.10:6443

name: kubernetes

contexts:-context:

cluster: kubernetes

user: kubernetes-admin

name: kubernetes-admin@kubernetes

current-context: kubernetes-admin@kubernetes

kind: Config

preferences: {}

users:- name: kubernetes-admin

user:

client-certificate-data: REDACTED

client-key-data: REDACTED

(2)kubectl config set-cluster:添加集群

root@VM-16-6-ubuntu:~# kubectl config set-cluster k8s1 --server=https://1.2.3.4

Cluster "k8s1" set.

查看配置文件:

root@VM-16-6-ubuntu:~# head -5 /etc/kubernetes/admin.conf

apiVersion: v1

clusters:-cluster:

server: https://1.2.3.4

name: k8s1

确认已经写入了配置文件.

root@VM-16-6-ubuntu:~# kubectl config view

apiVersion: v1

clusters:- cluster:

server: https://1.2.3.4

name: k8s1-cluster:

certificate-authority-data: REDACTED

server: https://148.70.251.10:6443

name: kubernetes

contexts:-context:

cluster: kubernetes

user: kubernetes-admin

name: kubernetes-admin@kubernetes

current-context: kubernetes-admin@kubernetes

kind: Config

preferences: {}

users:- name: kubernetes-admin

user:

client-certificate-data: REDACTED

client-key-data: REDACTED

(3)kubectl config get-clusters:查看kubeconfig中所有的cluster

root@VM-16-6-ubuntu:~# kubectl config get-clusters

NAME

k8s1

kubernetes

(4)kubectl config delete-cluster:刪除某个cluster

root@VM-16-6-ubuntu:~# kubectl config delete-cluster k8s1

deleted cluster k8s1 from/etc/kubernetes/admin.conf

root@VM-16-6-ubuntu:~# kubectl config get-clusters

NAME

kubernetes

(5)kubectl config get-context:获取所有的context

kubernetes中context类似“用户”的意思，这是多租户使用的的前提。

root@VM-16-6-ubuntu:~# kubectl config current-context

kubernetes-admin@kubernetes

(6)kubectl config set-context:添加一个context

root@VM-16-6-ubuntu:~# kubectl config set-context admin1@k8s1 --user=admin1

Context"admin1@k8s1"created.

root@VM-16-6-ubuntu:~# kubectl config get-contexts

CURRENT NAME CLUSTER AUTHINFO NAMESPACE

admin1@k8s1 admin1* kubernetes-admin@kubernetes kubernetes kubernetes-admin

(7)kubectl config delete-context:刪除一个context

root@VM-16-6-ubuntu:~# kubectl config delete-context admin1@k8s1

deleted context admin1@k8s1 from/etc/kubernetes/admin.conf

root@VM-16-6-ubuntu:~# kubectl config get-contexts

CURRENT NAME CLUSTER AUTHINFO NAMESPACE* kubernetes-admin@kubernetes kubernetes kubernetes-admin

(8)kubectl config current-context:查看当前所使用的context

root@VM-16-6-ubuntu:~# kubectl config current-context

kubernetes-admin@kubernetes

(9)kubectl config use-context:切换context

root@VM-16-6-ubuntu:~# kubectl config set-context admin1@k8s1 --user=admin1

Context"admin1@k8s1"created.

root@VM-16-6-ubuntu:~# kubectl config use-context admin1@k8s1

Switched to context"admin1@k8s1".

root@VM-16-6-ubuntu:~# kubectl config current-context

admin1@k8s1

(10)kubectl config set-credentials:添加一个用户

root@VM-16-6-ubuntu:~# kubectl config set-credentials admin1 --username=admin1 --password=abcd

User"admin1" set.

在kubeconfig中可以看到如下信息:

users:-name: admin1

user:

password: abcd

username: admin1

2.集群控制:kubectl create/apply/delete/label/edit/expose/scale

(1)kubectl create:创建pod

编写配置文件：

apiVersion: apps/v1

kind: Deployment

metadata:

name: deployment-example

spec:

replicas:2selector:

matchLabels:

app: nginx

template:

metadata:

labels:

app: nginx

spec:

containers:-name: nginx

image: nginx:1.10

集群创建以及查看：

root@VM-16-6-ubuntu:~/test# kubectl create -f nginx-deployment.yaml

deployment.apps"deployment-example"created

root@VM-16-6-ubuntu:~/test# kubectl get pods

NAME READY STATUS RESTARTS AGE

deployment-example-9956dd665-prkn9 0/1 ContainerCreating 044s

deployment-example-9956dd665-wwbvr 0/1 ContainerCreating 044s

root@VM-16-6-ubuntu:~/test# kubectl get pods

NAME READY STATUS RESTARTS AGE

deployment-example-9956dd665-prkn9 1/1 Running 04m

deployment-example-9956dd665-wwbvr 1/1 Running 04m

#显示标签信息：

root@VM-16-6-ubuntu:~/test# kubectl get pods --show-labels

NAME READY STATUS RESTARTS AGE LABELS

deployment-example-9956dd665-prkn9 1/1 Running 0 13m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-wwbvr 1/1 Running 0 13m app=nginx,pod-template-hash=551288221

(2)给pod打标签

root@VM-16-6-ubuntu:~/test# kubectl label pods/deployment-example-9956dd665-wwbvr status=healthy

pod"deployment-example-9956dd665-wwbvr"labeled

root@VM-16-6-ubuntu:~/test# kubectl get pods --show-labels

NAME READY STATUS RESTARTS AGE LABELS

deployment-example-9956dd665-prkn9 1/1 Running 0 14m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-wwbvr 1/1 Running 0 14m app=nginx,pod-template-hash=551288221,status=healthy

(3)编辑pod的配置文件

root@VM-16-6-ubuntu:~/test# kubectl edit deployment/deployment-example

deployment.extensions"deployment-example" edited

这个文件属于临时文件，现在将pod中的容器数量replicas变更为4。

查看pods信息：

root@VM-16-6-ubuntu:~/test# kubectl get pods --show-labels

NAME READY STATUS RESTARTS AGE LABELS

deployment-example-9956dd665-jpbvw 1/1 Running 0 10s app=nginx,pod-template-hash=551288221deployment-example-9956dd665-pmng2 1/1 Running 0 10s app=nginx,pod-template-hash=551288221deployment-example-9956dd665-prkn9 1/1 Running 0 17m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-wwbvr 1/1 Running 0 17m app=nginx,pod-template-hash=551288221,status=healthy

(4)使用kubectl scale也可以操作pod的yaml文件配置

直接修改配置文件的内容，而不需要打开文件。

root@VM-16-6-ubuntu:~/test# kubectl scale --replicas=10 deployment/deployment-example

deployment.extensions"deployment-example"scaled

root@VM-16-6-ubuntu:~/test# kubectl get pods --show-labels

NAME READY STATUS RESTARTS AGE LABELS

deployment-example-9956dd665-246zt 1/1 Running 0 8s app=nginx,pod-template-hash=551288221deployment-example-9956dd665-424r4 1/1 Running 0 8s app=nginx,pod-template-hash=551288221deployment-example-9956dd665-jpbvw 1/1 Running 0 14m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-pdcff 1/1 Running 0 8s app=nginx,pod-template-hash=551288221deployment-example-9956dd665-pmng2 1/1 Running 0 14m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-prkn9 1/1 Running 0 32m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-rwq8t 1/1 Running 0 8s app=nginx,pod-template-hash=551288221deployment-example-9956dd665-tnk99 1/1 Running 0 8s app=nginx,pod-template-hash=551288221deployment-example-9956dd665-vsbqk 1/1 Running 0 8s app=nginx,pod-template-hash=551288221deployment-example-9956dd665-wwbvr 1/1 Running 0 32m app=nginx,pod-template-hash=551288221,status=healthy

(5)通过kubectl apply恢复原始配置

root@VM-16-6-ubuntu:~/test# kubectl apply -f nginx-deployment.yaml

Warning: kubectl apply should be used on resource created by either kubectl create--save-config or kubectl apply

deployment.apps"deployment-example"configured

root@VM-16-6-ubuntu:~/test# kubectl get pods --show-labels

NAME READY STATUS RESTARTS AGE LABELS

deployment-example-9956dd665-246zt 0/1 Terminating 0 3m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-424r4 0/1 Terminating 0 3m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-jpbvw 0/1 Terminating 0 17m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-pdcff 0/1 Terminating 0 3m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-pmng2 0/1 Terminating 0 17m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-prkn9 1/1 Running 0 35m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-rwq8t 1/1 Terminating 0 3m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-vsbqk 0/1 Terminating 0 3m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-wwbvr 1/1 Running 0 35m app=nginx,pod-template-hash=551288221,status=healthy

root@VM-16-6-ubuntu:~/test# kubectl get pods --show-labels

NAME READY STATUS RESTARTS AGE LABELS

deployment-example-9956dd665-246zt 0/1 Terminating 0 3m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-jpbvw 0/1 Terminating 0 17m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-pdcff 0/1 Terminating 0 3m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-prkn9 1/1 Running 0 35m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-rwq8t 0/1 Terminating 0 3m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-wwbvr 1/1 Running 0 35m app=nginx,pod-template-hash=551288221,status=healthy

root@VM-16-6-ubuntu:~/test# kubectl get pods --show-labels

NAME READY STATUS RESTARTS AGE LABELS

deployment-example-9956dd665-prkn9 1/1 Running 0 35m app=nginx,pod-template-hash=551288221deployment-example-9956dd665-wwbvr 1/1 Running 0 35m app=nginx,pod-template-hash=551288221,status=healthy

(6)通过kubectl delete删除pod

root@VM-16-6-ubuntu:~/test#kubectl delete -f nginx-deployment.yaml

deployment.apps"deployment-example"deleted

root@VM-16-6-ubuntu:~/test# kubectl get pods --show-labels

NAME READY STATUS RESTARTS AGE LABELS

deployment-example-9956dd665-prkn9 0/1 Terminating 0 37m app=nginx,pod-template-hash=551288221root@VM-16-6-ubuntu:~/test# kubectl get pods --show-labels

No resources found.

3.集群查看和问题调试:kubectl get/describe/logs/exec/attach

(1)kubectl get：获取对象的信息，可以是pod、node等

root@VM-16-6-ubuntu:~/test# kubectl get pods

NAME READY STATUS RESTARTS AGE

deployment-example-9956dd665-2ksc4 1/1 Running 010m

deployment-example-9956dd665-rdwwc 1/1 Running 010m

root@VM-16-6-ubuntu:~/test# kubectl get nodes

NAME STATUS ROLES AGE VERSION

vm-0-3-ubuntu Ready 2d v1.10.2vm-16-6-ubuntu Ready master 2d v1.10.2vm-16-8-ubuntu Ready 2d v1.10.2

(2)kubeadm descrbe:查看特定资源或资源组的描述信息

root@VM-16-6-ubuntu:~/test# kubectl describe pods/deployment-example-9956dd665-rdwwc

Name: deployment-example-9956dd665-rdwwc

Namespace: default

Node: vm-16-8-ubuntu/172.27.16.8Start Time: Fri,21 Jun 2019 22:32:45 +0800Labels: app=nginx

pod-template-hash=551288221Annotations:Status: Running

IP:192.168.20.1Controlled By: ReplicaSet/deployment-example-9956dd665

Containers:

nginx:

Container ID: docker://dd4f3ca81bbc5e6dc56f33d3c3bdb1700212e65a6024956e2bf45fc81614ee42

Image: nginx:1.10Image ID: docker-pullable://nginx@sha256:6202beb06ea61f44179e02ca965e8e13b961d12640101fca213efbfd145d7575

Port: Host Port:State: Running

Started: Fri,21 Jun 2019 22:32:46 +0800Ready: True

Restart Count:0Environment:Mounts:/var/run/secrets/kubernetes.io/serviceaccount from default-token-44qwv (ro)

Conditions:

Type Status

Initialized True

Ready True

PodScheduled True

Volumes:

default-token-44qwv:

Type: Secret (a volume populated by a Secret)

SecretName: default-token-44qwv

Optional:falseQoS Class: BestEffort

Node-Selectors: Tolerations: node.kubernetes.io/not-ready:NoExecute for300s

node.kubernetes.io/unreachable:NoExecute for300s

Events:

Type Reason Age From Message---- ------ ---- ---- -------Normal Scheduled 50s default-scheduler Successfully assigned deployment-example-9956dd665-rdwwc to vm-16-8-ubuntu

Normal SuccessfulMountVolume 50s kubelet, vm-16-8-ubuntu MountVolume.SetUp succeeded for volume "default-token-44qwv"Normal Pulled 49s kubelet, vm-16-8-ubuntu Container image "nginx:1.10"already present on machine

Normal Created 49s kubelet, vm-16-8-ubuntu Created container

Normal Started 49s kubelet, vm-16-8-ubuntu Started container

(3)kubeadm exec在容器内执行命令

root@VM-16-6-ubuntu:~/test# kubectl exec deployment-example-9956dd665-rdwwc -- cat /etc/nginx/nginx.conf

user nginx;

worker_processes1;

error_log/var/log/nginx/error.log warn;

pid/var/run/nginx.pid;

events {

worker_connections1024;

}

http {

include/etc/nginx/mime.types;

default_type application/octet-stream;

log_format main'$remote_addr - $remote_user [$time_local] "$request"'

'$status $body_bytes_sent "$http_referer"'

'"$http_user_agent" "$http_x_forwarded_for"';

access_log/var/log/nginx/access.log main;

sendfile on;

#tcp_nopush on;

keepalive_timeout65;

#gzipon;

include/etc/nginx/conf.d/*.conf;

}

(4)kubectl logs查看容器的日志输出

root@VM-16-6-ubuntu:~/test# kubectl logs pods/deployment-example-9956dd665-rdwwc

使用-f参数可以查看实时日志输出。

(5)kubectl attach进入到容器内部

root@VM-16-6-ubuntu:~/test# kubectl attach deployment-example-9956dd665-rdwwc