K8s之kubectl命令行工具常用命令
kubectl管理
Kubectl是管理k8s集群的命令行工具，通过生成的json格式传递给apiserver进行创建、查看、管理的操作
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注意：此处需要用到我们之前部署的K8s多节点的部署环境，如果还未部署的可以参考我的上篇文章：https://blog.csdn.net/JarryZho/article/details/104212822
常用命令行：
`查看帮助命令`
[root@master1 ~]# kubectl --help
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.
expose 使用 replication controller, service, deployment 或者 pod 并暴露它作为一个 新的
Kubernetes Service
run 在集群中运行一个指定的镜像
set 为 objects 设置一个指定的特征
Basic Commands (Intermediate):
explain 查看资源的文档
get 显示一个或更多 resources
edit 在服务器上编辑一个资源
delete Delete resources by filenames, stdin, resources and names, or by resources and label selector
Deploy Commands:
rollout Manage the rollout of a resource
scale 为 Deployment, ReplicaSet, Replication Controller 或者 Job 设置一个新的副本数量
autoscale 自动调整一个 Deployment, ReplicaSet, 或者 ReplicationController 的副本数量
Cluster Management Commands:
certificate 修改 certificate 资源.
cluster-info 显示集群信息
top Display Resource (CPU/Memory/Storage) usage.
cordon 标记 node 为 unschedulable
uncordon 标记 node 为 schedulable
drain Drain node in preparation for maintenance
taint 更新一个或者多个 node 上的 taints
Troubleshooting and Debugging Commands:
describe 显示一个指定 resource 或者 group 的 resources 详情
logs 输出容器在 pod 中的日志
attach Attach 到一个运行中的 container
exec 在一个 container 中执行一个命令
port-forward Forward one or more local ports to a pod
proxy 运行一个 proxy 到 Kubernetes API server
cp 复制 files 和 directories 到 containers 和从容器中复制 files 和 directories.
auth Inspect authorization
Advanced Commands:
apply 通过文件名或标准输入流(stdin)对资源进行配置
patch 使用 strategic merge patch 更新一个资源的 field(s)
replace 通过 filename 或者 stdin替换一个资源
wait Experimental: Wait for a specific condition on one or many resources.
convert 在不同的 API versions 转换配置文件
Settings Commands:
label 更新在这个资源上的 labels
annotate 更新一个资源的注解
completion Output shell completion code for the specified shell (bash or zsh)
Other Commands:
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 修改 kubeconfig 文件
plugin Provides utilities for interacting with plugins.
version 输出 client 和 server 的版本信息接下来我们以项目的形式讲其中的命令
其步骤如下：创建一>发布一>更新一>回滚一>删除
1.创建nginx
#语法：kubectl run NAME --image=image [--env="key=value"参数] [--port=port端口] [--replicas=replicas副本集] [--dry-run=bool状态] [--overrides=inline-json] [--command命令] -- [COMMAND] [args...] [options]`
`示例：`
[root@master1 k8s]# kubectl run nginx-deployment --image=nginx --port=80 --replicas=3
kubectl run --generator=deployment/apps.v1beta1 is DEPRECATED and will be removed in a future version. Use kubectl create instead.
deployment.apps/nginx-deployment created
[root@master1 k8s]# kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx-dbddb74b8-7hdfj 1/1 Running 0 4d18h
`nginx-deployment-5477945587-2dljt 1/1 Running 0 68s`
`nginx-deployment-5477945587-tt8vx 1/1 Running 0 68s`
`nginx-deployment-5477945587-wsb69 1/1 Running 0 68s`
#最后三个就是我们新创建的副本集2.发布nginx service提供负载均衡的功能
#语法：kubectl expose (-f FILENAME | TYPE NAME) [--port=port群集之间内部通信的端口] [--protocol=TCP|UDP|SCTP] [--target-port对外暴露的端口=number-or-name] [--name=name指定名称] [--external-ip=external-ip-of-service] [--type=type指定类型] [options]
`示例：`
[root@master1 k8s]# kubectl expose deployment nginx-deployment --port=80 --target-port=80 --name=nginx-deployment-service --type=NodePort
service/nginx-deployment-service exposed
`查看发布`
[root@master1 k8s]# kubectl get pods,svc #此处svc位service服务组件的缩写
NAME READY STATUS RESTARTS AGE
pod/nginx-dbddb74b8-7hdfj 1/1 Running 0 4d19h
pod/nginx-deployment-5477945587-2dljt 1/1 Running 0 13m
pod/nginx-deployment-5477945587-tt8vx 1/1 Running 0 13m
pod/nginx-deployment-5477945587-wsb69 1/1 Running 0 13m
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.0.0.1 443/TCP 6d19h
service/nginx-service NodePort 10.0.0.242 80:40422/TCP 111s
#此时对外暴露的端口为40422
`查看资源对象简写`
[root@master1 k8s]# kubectl api-resources
NAME SHORTNAMES APIGROUP NAMESPACED
componentstatuses cs false
configmaps cm true
endpoints ep true
events ev true
limitranges limits true
namespaces ns false
nodes no false
persistentvolumeclaims pvc true
persistentvolumes pv false
pods po true
replicationcontrollers rc true
resourcequotas quota true
serviceaccounts sa true
services svc true
customresourcedefinitions crd,crds apiextensions.k8s.io false
daemonsets ds apps true
deployments deploy apps true
replicasets rs apps true
statefulsets sts apps true
horizontalpodautoscalers hpa autoscaling true
cronjobs cj batch true
certificatesigningrequests csr certificates.k8s.io false
events ev events.k8s.io true
daemonsets ds extensions true
deployments deploy extensions true
ingresses ing extensions true
networkpolicies netpol extensions true
podsecuritypolicies psp extensions false
replicasets rs extensions true
networkpolicies netpol networking.k8s.io true
poddisruptionbudgets pdb policy true
podsecuritypolicies psp policy false
priorityclasses pc scheduling.k8s.io false
storageclasses sc storage.k8s.io false
`查看关联后端的节点`
[root@master1 k8s]# kubectl get endpoints
NAME ENDPOINTS AGE
kubernetes 192.168.18.128:6443,192.168.18.132:6443 7d4h
nginx-deployment-service 172.17.32.4:80,172.17.40.2:80,172.17.40.3:80 17s
`网络状态详细信息`
[root@master1 ~]# kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE
nginx-dbddb74b8-7hdfj 1/1 Running 0 5d5h 172.17.32.2 192.168.18.148
nginx-deployment-5477945587-2dljt 1/1 Running 0 10h 172.17.40.3 192.168.18.145
nginx-deployment-5477945587-tt8vx 1/1 Running 0 10h 172.17.40.2 192.168.18.145
nginx-deployment-5477945587-wsb69 1/1 Running 0 10h 172.17.32.4 192.168.18.148
`服务暴露的端口`
[root@master1 ~]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.0.0.1 443/TCP 7d5h
nginx-deployment-service NodePort 10.0.0.50 80:48330/TCP 70m
`在node1操作，查看负载均衡端口48330`
`k8s里kube-proxy支持三种模式，在v1.8之前我们使用的是iptables以及userspace两种模式，在k8s1.8之后引入了ipvs模式`
[root@node1 ~]# yum install ipvsadm -y
[root@node1 ~]# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.18.148:48330 rr
-> 172.17.32.4:80 Masq 1 0 0
-> 172.17.40.2:80 Masq 1 0 0
-> 172.17.40.3:80 Masq 1 0 0
#对外提供端口48330，调度算法为rr轮询
`在node2操作 同样安装ipvsadmin工具查看`
[root@node2 ~]# yum install ipvsadm -y
[root@node2 ~]# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.18.145:48330 rr
-> 172.17.32.4:80 Masq 1 0 0
-> 172.17.40.2:80 Masq 1 0 0
-> 172.17.40.3:80 Masq 1 0 0 我们现在宿主机中使用浏览器访问192.168.18.148:48330和192.168.18.145:48330都可以访问到nginx的主页，然后再查看日志
`在master1操作查看访问日志（注意：如果访问其他node无法访问检查proxy组件）`
[root@master1 ~]# kubectl get pods #此时会有三个副本集
NAME READY STATUS RESTARTS AGE
nginx-dbddb74b8-7hdfj 1/1 Running 0 5d5h
nginx-deployment-5477945587-2dljt 1/1 Running 0 10h
nginx-deployment-5477945587-tt8vx 1/1 Running 0 10h
nginx-deployment-5477945587-wsb69 1/1 Running 0 10h
`此时回头查看访问日志：`
[root@master1 ~]# kubectl logs nginx-deployment-5477945587-2dljt
172.17.40.1 - - [12/Feb/2020:11:44:46 +0000] "GET / HTTP/1.1" 200 612 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.131 Safari/537.36" "-"
172.17.40.1 - - [12/Feb/2020:11:44:46 +0000] "GET /favicon.ico HTTP/1.1" 404 555 "http://192.168.18.145:48330/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.131 Safari/537.36" "-"
[root@master1 ~]# kubectl logs nginx-deployment-5477945587-tt8vx
[root@master1 ~]# kubectl logs nginx-deployment-5477945587-wsb69
172.17.32.1 - - [12/Feb/2020:11:47:07 +0000] "GET / HTTP/1.1" 200 612 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.131 Safari/537.36" "-"
172.17.32.1 - - [12/Feb/2020:11:47:07 +0000] "GET /favicon.ico HTTP/1.1" 404 555 "http://192.168.18.148:48330/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/79.0.3945.131 Safari/537.36" "-"
#此时nginx-deployment-5477945587-wsb69和nginx-deployment-5477945587-2dljt分别被访问了nginx的主页，说明业务已经成功发布，而且对方用的是轮询的方式访问多个Pod资源3.更新nginx 为1.14版本
查看nginx版本步骤：F12打开开发者选项--》F5刷新访问---》找到network---》点击name---》找到headers头部信息
[root@master1 ~]# kubectl set image deployment/nginx-deployment nginx-deployment=nginx:1.14
deployment.extensions/nginx-deployment image updated
`处于动态监听状态，此时可以查看监控状态`
[root@master1 ~]# kubectl get pods -w
NAME READY STATUS RESTARTS AGE
nginx-6c94d899fd-8pf48 1/1 Running 0 3m54s
nginx-deployment-5477945587-2dljt 1/1 Running 0 10h
nginx-deployment-5477945587-tt8vx 1/1 Running 0 10h
nginx-deployment-5477945587-wsb69 1/1 Running 0 10h
nginx-deployment-8f66bcd89-jncdr 0/1 ContainerCreating 0 7s
#此时哦我们可以按Ctrl+c中断监听，这样更新速度快验证：我们再次重载宿主机中的nginx主页，此时在开发者选项中看到的头部信息里nginx的版本更新为了1.14.2
4.回滚nginx
`查看历史版本`
[root@master1 ~]# kubectl rollout history deployment/nginx-deployment
deployment.extensions/nginx-deployment
REVISION CHANGE-CAUSE
1 #1.17版本
2 #1.14版本
`执行回滚到上一次`
[root@master1 ~]# kubectl rollout undo deployment/nginx-deployment
deployment.extensions/nginx-deployment
`检查回滚状态`
[root@master1 ~]# kubectl rollout status deployment/nginx-deployment
Waiting for deployment "nginx-deployment" rollout to finish: 1 out of 3 new replicas have been updated...
Waiting for deployment "nginx-deployment" rollout to finish: 1 out of 3 new replicas have been updated...
Waiting for deployment "nginx-deployment" rollout to finish: 2 out of 3 new replicas have been updated...
Waiting for deployment "nginx-deployment" rollout to finish: 2 out of 3 new replicas have been updated...
Waiting for deployment "nginx-deployment" rollout to finish: 2 out of 3 new replicas have been updated...
Waiting for deployment "nginx-deployment" rollout to finish: 1 old replicas are pending termination...
Waiting for deployment "nginx-deployment" rollout to finish: 1 old replicas are pending termination...
deployment "nginx-deployment" successfully rolled out
#最终显示成功回滚 验证：再回到宿主机的浏览器刷新nginx主页，此时在页面开发者选择的头部信息中看到的nginx版本就恢复到了之前的1.17.8
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5.删除nginx
`查看deployment`
[root@master1 ~]# kubectl get deploy
NAME DESIRED CURRENT UP-TO-DATE AVAILABLE AGE
nginx-deployment 3 3 3 3 11h
[root@master1 ~]# kubectl delete deployment/nginx-deployment
deployment.extensions "nginx-deployment" deleted
[root@master1 ~]# kubectl get deploy
No resources found.
[root@master1 ~]# kubectl get pods
No resources found.
`删除服务SVC`
[root@master1 ~]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.0.0.1 443/TCP 7d6h
nginx-deployment-service NodePort 10.0.0.50 80:48330/TCP 142m
[root@master1 ~]# kubectl delete svc/nginx-deployment-service
service "nginx-deployment-service" deleted #此步骤为删除步骤
[root@master1 ~]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.0.0.1 443/TCP 7d7h 6.其它
`查看具体资源的详细信息`
[root@master1 ~]# kubectl run nginx-deployment --image=nginx --port=80 --replicas=3
kubectl run --generator=deployment/apps.v1beta1 is DEPRECATED and will be removed in a future version. Use kubectl create instead.
deployment.apps/nginx-deployment created
[root@master1 ~]# kubectl get pods
NAME READY STATUS RESTARTS AGE
nginx-6c94d899fd-8pf48 1/1 Running 0 54m
nginx-deployment-5477945587-f5dsm 1/1 Running 0 15s
nginx-deployment-5477945587-hmgd2 1/1 Running 0 15s
nginx-deployment-5477945587-pl2hn 1/1 Running 0 15s
[root@master1 ~]# kubectl describe pod nginx-deployment-5477945587-f5dsm
Name: nginx-deployment-5477945587-f5dsm
Namespace: default
Priority: 0
PriorityClassName:
Node: 192.168.18.145/192.168.18.145
Start Time: Wed, 12 Feb 2020 21:04:40 +0800
Labels: pod-template-hash=5477945587
run=nginx-deployment
Annotations:
Status: Running
IP: 172.17.40.2
Controlled By: ReplicaSet/nginx-deployment-5477945587
Containers:
nginx-deployment:
Container ID: docker://670cb7230f200279b2accb344766e621ab97d279c8585cc27bd4e519dac9e677
Image: nginx
Image ID: docker-pullable://nginx@sha256:ad5552c786f128e389a0263104ae39f3d3c7895579d45ae716f528185b36bc6f
Port: 80/TCP
Host Port: 0/TCP
State: Running
Started: Wed, 12 Feb 2020 21:04:44 +0800
Ready: True
Restart Count: 0
Environment:
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-pbr9p (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
default-token-pbr9p:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-pbr9p
Optional: false
QoS Class: BestEffort
Node-Selectors:
Tolerations: node.kubernetes.io/not-ready:NoExecute for 300s
node.kubernetes.io/unreachable:NoExecute for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 19m default-scheduler Successfully assigned default/nginx-deployment-5477945587-f5dsm to 192.168.18.145
Normal Pulling 19m kubelet, 192.168.18.145 pulling image "nginx"
Normal Pulled 19m kubelet, 192.168.18.145 Successfully pulled image "nginx"
Normal Created 19m kubelet, 192.168.18.145 Created container
Normal Started 19m kubelet, 192.168.18.145 Started container
`查看deployment资源`
[root@master1 ~]# kubectl describe deployment/nginx-deployment
Name: nginx-deployment
Namespace: default
CreationTimestamp: Wed, 12 Feb 2020 21:04:40 +0800
Labels: run=nginx-deployment
Annotations: deployment.kubernetes.io/revision: 1
Selector: run=nginx-deployment
Replicas: 3 desired | 3 updated | 3 total | 3 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Pod Template:
Labels: run=nginx-deployment
Containers:
nginx-deployment:
Image: nginx
Port: 80/TCP
Host Port: 0/TCP
Environment:
Mounts:
Volumes:
Conditions:
Type Status Reason
---- ------ ------
Available True MinimumReplicasAvailable
Progressing True NewReplicaSetAvailable
OldReplicaSets:
NewReplicaSet: nginx-deployment-5477945587 (3/3 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ScalingReplicaSet 21m deployment-controller Scaled up replica set nginx-deployment-5477945587 to 3
`进入pod`
[root@master1 ~]# kubectl exec -it nginx-deployment-5477945587-f5dsm bash
root@nginx-deployment-5477945587-f5dsm:/# 问题集锦及原因：
`1:状态为NotReady`
[root@localhost bin]# kubectl get node
NAME STATUS ROLES AGE VERSION
192.168.195.150 NotReady 6d19h v1.12.3
192.168.195.151 NotReady 6d18h v1.12.3
#原因: node 节点无法连接apiserver
1)单节点：master节点 apiserver服务是否正常运行
systemctl restart kube-apiserver 失败
cat /var/log/messages 日志（第一次部署：检查证书）
2）多节点：如果api-server运行正常
检查：负载均衡中的VIP，检查nginx调度 四层转发模块配置
`2：kubectl get pods 查询podes资源状态`
NAME READY STATUS RESTARTS AGE
nginx-7697996758-jg47q 0/1 Pending 0 93s
nginx-7697996758-k967k 0/1 Pending 0 93s
nginx-7697996758-p5n8m 0/1 Pending 0 93s
无法配置资源到node节点中进行创建（处于pending状态）
检查node节点中kubelet服务组件，kubeconfig配置
`3：客户无法访问pods发布的服务`
ipvsadm -L -n 负载均衡 对外提供的端口44888
#正常情况每个node应该是以下状态：
TCP 192.168.195.151:44888 rr
-> 172.17.68.2:80 Masq 1 0 0
-> 172.17.68.3:80 Masq 1 0 0
-> 172.17.86.2:80 Masq 1 0 0
#原因：kube-proxy组件服务 名称栏目：K8s之kubectl命令行工具常用命令
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