再战 k8s：kebuctl
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文章目录
简介
kubectl 是 Kubernetes 的命令行工具（CLI），是 Kubernetes 用户和管理员必备的管理工具。
在管理工具界面使用kubectl语法运行如下命令：
kubectl [command] [TYPE] [NAME] [flags]
（1）comand：指定要对资源执行的操作，例如 create、get、describe 和 delete 。
（2）TYPE：指定资源类型，资源类型是大小写敏感的，开发者能够以单数、复数和缩略的形式。
（3）NAME：指定资源的名称，名称也大小写敏感的。如果省略名称，则会显示所有的资源。
（4）flags：指定可选的参数。例如，可用-s 或者–server 参数指定 Kubernetes API server 的地址和端。
常用命令
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 Server
cp 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
示例
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.
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.
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
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.
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: 2
selector:
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 0 44s
deployment-example-9956dd665-wwbvr 0/1 ContainerCreating 0 44s
root@VM-16-6-ubuntu:~/test# kubectl get pods
NAME READY STATUS RESTARTS AGE
deployment-example-9956dd665-prkn9 1/1 Running 0 4m
deployment-example-9956dd665-wwbvr 1/1 Running 0 4m
#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=551288221
deployment-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=551288221
deployment-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=551288221
deployment-example-9956dd665-pmng2 1/1 Running 0 10s app=nginx,pod-template-hash=551288221
deployment-example-9956dd665-prkn9 1/1 Running 0 17m app=nginx,pod-template-hash=551288221
deployment-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=551288221
deployment-example-9956dd665-424r4 1/1 Running 0 8s app=nginx,pod-template-hash=551288221
deployment-example-9956dd665-jpbvw 1/1 Running 0 14m app=nginx,pod-template-hash=551288221
deployment-example-9956dd665-pdcff 1/1 Running 0 8s app=nginx,pod-template-hash=551288221
deployment-example-9956dd665-pmng2 1/1 Running 0 14m app=nginx,pod-template-hash=551288221
deployment-example-9956dd665-prkn9 1/1 Running 0 32m app=nginx,pod-template-hash=551288221
deployment-example-9956dd665-rwq8t 1/1 Running 0 8s app=nginx,pod-template-hash=551288221
deployment-example-9956dd665-tnk99 1/1 Running 0 8s app=nginx,pod-template-hash=551288221
deployment-example-9956dd665-vsbqk 1/1 Running 0 8s app=nginx,pod-template-hash=551288221
deployment-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=551288221
deployment-example-9956dd665-424r4 0/1 Terminating 0 3m app=nginx,pod-template-hash=551288221
deployment-example-9956dd665-jpbvw 0/1 Terminating 0 17m app=nginx,pod-template-hash=551288221
deployment-example-9956dd665-pdcff 0/1 Terminating 0 3m app=nginx,pod-template-hash=551288221
deployment-example-9956dd665-pmng2 0/1 Terminating 0 17m app=nginx,pod-template-hash=551288221
deployment-example-9956dd665-prkn9 1/1 Running 0 35m app=nginx,pod-template-hash=551288221
deployment-example-9956dd665-rwq8t 1/1 Terminating 0 3m app=nginx,pod-template-hash=551288221
deployment-example-9956dd665-vsbqk 0/1 Terminating 0 3m app=nginx,pod-template-hash=551288221
deployment-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=551288221
deployment-example-9956dd665-jpbvw 0/1 Terminating 0 17m app=nginx,pod-template-hash=551288221
deployment-example-9956dd665-pdcff 0/1 Terminating 0 3m app=nginx,pod-template-hash=551288221
deployment-example-9956dd665-prkn9 1/1 Running 0 35m app=nginx,pod-template-hash=551288221
deployment-example-9956dd665-rwq8t 0/1 Terminating 0 3m app=nginx,pod-template-hash=551288221
deployment-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=551288221
deployment-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=551288221
root@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 0 10m
deployment-example-9956dd665-rdwwc 1/1 Running 0 10m
root@VM-16-6-ubuntu:~/test# kubectl get nodes
NAME STATUS ROLES AGE VERSION
vm-0-3-ubuntu Ready <none> 2d v1.10.2
vm-16-6-ubuntu Ready master 2d v1.10.2
vm-16-8-ubuntu Ready <none> 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/172.27.16.8
Start Time: Fri, 21 Jun 2019 22:32:45 +0800
Labels: app=nginx
pod-template-hash=551288221
Annotations: <none>
Status: Running
IP: 192.168.20.1
Controlled By: ReplicaSet/deployment-example-9956dd665
Containers:
nginx:
Container ID: docker://dd4f3ca81bbc5e6dc56f33d3c3bdb1700212e65a6024956e2bf45fc81614ee42
Image: nginx:1.10
Image ID: docker-pullable://nginx@sha256:6202beb06ea61f44179e02ca965e8e13b961d12640101fca213efbfd145d7575
Port: <none>
Host Port: <none>
State: Running
Started: Fri, 21 Jun 2019 22:32:46 +0800
Ready: True
Restart Count: 0
Environment: <none>
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: 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 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_processes 1;
error_log /var/log/nginx/error.log warn;
pid /var/run/nginx.pid;
events
worker_connections 1024;
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_timeout 65;
#gzip on;
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
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