一、namespace操作
1）列出集群中所有API组名/版本号：
kubectl api-versions
输出：
Copy admissionregistration.k8s.io/v1
admissionregistration.k8s.io/v1beta1
apiextensions.k8s.io/v1
apiextensions.k8s.io/v1beta1
apiregistration.k8s.io/v1
apiregistration.k8s.io/v1beta1
apps/v1
authentication.k8s.io/v1
authentication.k8s.io/v1beta1
authorization.k8s.io/v1
authorization.k8s.io/v1beta1
autoscaling/v1
autoscaling/v2beta1
autoscaling/v2beta2
batch/v1
batch/v1beta1
certificates.k8s.io/v1beta1
coordination.k8s.io/v1
coordination.k8s.io/v1beta1
discovery.k8s.io/v1beta1
events.k8s.io/v1beta1
extensions/v1beta1
networking.k8s.io/v1
networking.k8s.io/v1beta1
node.k8s.io/v1beta1
policy/v1beta1
rbac.authorization.k8s.io/v1
rbac.authorization.k8s.io/v1beta1
scheduling.k8s.io/v1
scheduling.k8s.io/v1beta1
storage.k8s.io/v1
storage.k8s.io/v1beta1
v1 2）列出集群名称空间：
kubectl get namespaces
输出结果：
Copy NAME STATUS AGE
default Active 2d20h
kube-node-lease Active 2d20h
kube-public Active 2d20h
kube-system Active 2d20h 3）创建新的名称空间：
kubectl create namespace new-space-name
以上namespace均可以简写成ns，如：kubectl create ns new-space-name
4）列出集群内所有名称空间下所有pod：
kubectl get pod --all-namespaces
二、Pod操作
1）根据配置清单创建pod：
kubectl apply -f new-pod.yaml
2）删除pod：
kubectl delete pods pod-name
3）查看pod：
kubectl get pods
4）通过镜像文件直接创建pod和无状态应用：
Copy kubectl create deployment test1 --image=maxidea/flask-demo-app:v1.0 5）查看一下对应的pod和无状态应用：
Copy $ kubectl get pods
NAME READY STATUS RESTARTS AGE
test1-86d54d9655-q9lv5 1/1 Running 0 5m15s
$ kubectl get deploy
NAME READY UP-TO-DATE AVAILABLE AGE
test1 1/1 1 1 5m30s 访问这个服务，首先查看一下它的ip地址，可以看到它被部署到哪个节点上去（这里被部署到36工作节点上），使用命令格式：
kubectl get pods -o wide
Copy $ kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
test1-86d54d9655-q9lv5 1/1 Running 0 7m40s 10.244.2.2 36 <none> <none>
$ curl 10.244.2.2
flask-demo-app v1.0 / ClientIP: 10.244.0.0, ServerName: test1-86d54d9655-q9lv5, ServerIP: 10.244.2.2! 6）查看pod的配置清单
Copy $ kubectl create deployment test2 --image=maxidea/flask-demo-app:v1.0 --dry-run=client -o yaml
apiVersion: apps/v1
kind: Deployment
metadata:
creationTimestamp: null
labels:
app: test2
name: test2
spec:
replicas: 1
selector:
matchLabels:
app: test2
strategy: {}
template:
metadata:
creationTimestamp: null
labels:
app: test2
spec:
containers:
- image: maxidea/flask-demo-app:v1.0
name: flask-demo-app
resources: {}
status: {} 7）查看pod的label
kubectl get pods --show-labels
Copy NAME READY STATUS RESTARTS AGE LABELS
new-pod 1/1 Running 0 15h <none>
test1-86d54d9655-q9lv5 1/1 Running 0 18h app=test1,pod-template-hash=86d54d9655
test2-69444f54b-4phj2 1/1 Running 0 7m40s app=test2,pod-template-hash=69444f54b 7）查看指定名称空间下pod的资源使用情况
kubectl top pods -n [namespaces]
例如：
Copy [root@consumer-prd-paas-k8s-masterb-0 ~]# kubectl top pods -n momtest
NAME CPU(cores) MEMORY(bytes)
r-49b86 132m 249Mi
r-569wf 177m 353Mi
r-5g9jp 168m 284Mi
r-6sp9t 164m 237Mi
r-859fw 154m 263Mi
r-8ggdz 183m 260Mi 对指定pod资源状态自动刷新：
watch 'kubectl top pods -n momtest r-vqnc2'
8）查看每个节点主机资源使用情况
kubectl top node
三、Service操作
1）创建service
kubectl create service clusterip test1 --tcp=80
这里要注意，如果需要pod自动关联这个service，service的名字需要和pod一致。
查看这个创建的service：
Copy $ kubectl get service
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 3d4h
test1 ClusterIP 10.102.176.227 <none> 80/TCP 18s 查看service相关详细信息：
Copy $ kubectl describe service test1
Name: test1
Namespace: default
Labels: app=test1
Annotations: <none>
Selector: app=test1
Type: ClusterIP
IP: 10.102.176.227
Port: 80 80/TCP
TargetPort: 80/TCP
Endpoints: 10.244.2.2:80
Session Affinity: None
Events: <none> 这里看到pod test1已经作为这个service的Endpoints了。
从同一集群的其他pod（用kubectl exec -it pod_name -- /bin/sh进入）访问这个service，注意地址结构：[service name].[namespace].svc.[cluster domain]也可以使用这个service的ip地址访问：10.102.176.227
Copy # curl test1.default.svc.cluster.local
flask-demo-app v1.0 / ClientIP: 10.244.1.3, ServerName: test1-86d54d9655-q9lv5, ServerIP: 10.244.2.2! 2）扩展/缩小service下的pod个数
例如，把test1的副本数量扩展/缩少到三个（用同一命令指定数量即可）：
kubectl scale deployment/test1 --replicas=3
Copy $ kubectl get pods -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
new-pod 1/1 Running 0 18h 10.244.1.3 35 <none> <none>
test1-86d54d9655-c9h5m 1/1 Running 0 84s 10.244.1.4 35 <none> <none>
test1-86d54d9655-htbkd 1/1 Running 0 84s 10.244.3.4 37 <none> <none>
test1-86d54d9655-q9lv5 1/1 Running 0 21h 10.244.2.2 36 <none> <none> 可以看到在三个工作节点上会自动生成另外两个一样的pod。
Copy flask-demo-app v1.0 / ClientIP: 10.244.1.3, ServerName: test1-86d54d9655-htbkd, ServerIP: 10.244.3.4!
flask-demo-app v1.0 / ClientIP: 10.244.1.3, ServerName: test1-86d54d9655-q9lv5, ServerIP: 10.244.2.2!
flask-demo-app v1.0 / ClientIP: 10.244.1.3, ServerName: test1-86d54d9655-c9h5m, ServerIP: 10.244.1.4! 3）service的iptable规则
集群每创建一个新的pod，都会在节点宿主机的iptables上创建对应的新规则，例如：
Copy # iptables -t nat -S KUBE-SERVICES | grep test1
-A KUBE-SERVICES ! -s 10.244.0.0/16 -d 10.102.176.227/32 -p tcp -m comment --comment "default/test1:80 cluster IP" -m tcp --dport 80 -j KUBE-MARK-MASQ
-A KUBE-SERVICES -d 10.102.176.227/32 -p tcp -m comment --comment "default/test1:80 cluster IP" -m tcp --dport 80 -j KUBE-SVC-VRCN2UH6RARGOJZA
# iptables -t nat -S KUBE-SVC-VRCN2UH6RARGOJZA
-N KUBE-SVC-VRCN2UH6RARGOJZA
-A KUBE-SVC-VRCN2UH6RARGOJZA -m comment --comment "default/test1:80" -m statistic --mode random --probability 0.33333333349 -j KUBE-SEP-M4LMZLRGTFEOZERX
-A KUBE-SVC-VRCN2UH6RARGOJZA -m comment --comment "default/test1:80" -m statistic --mode random --probability 0.50000000000 -j KUBE-SEP-LL5YVFAV2NKPJ2W3
-A KUBE-SVC-VRCN2UH6RARGOJZA -m comment --comment "default/test1:80" -j KUBE-SEP-OSFWLWIVOCAZBH6N
# iptables -t nat -S KUBE-SEP-M4LMZLRGTFEOZERX
-N KUBE-SEP-M4LMZLRGTFEOZERX
-A KUBE-SEP-M4LMZLRGTFEOZERX -s 10.244.1.4/32 -m comment --comment "default/test1:80" -j KUBE-MARK-MASQ
-A KUBE-SEP-M4LMZLRGTFEOZERX -p tcp -m comment --comment "default/test1:80" -m tcp -j DNAT [unsupported revision] 完整的iptables规则如下图：
4）service的ipvs规则
对于使用ipvs的集群，上述规则在ipvs下显示如下，对比iptables，ipvs更为简单和高效：（通过修改kube-proxy的configMap里的mode字段为“ipvs”来配置）
工作节点上安装apt install ipvsadm
Copy # ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 10.96.0.1:443 rr
-> 192.168.2.31:6443 Masq 1 0 0
-> 192.168.2.32:6443 Masq 1 0 0
-> 192.168.2.33:6443 Masq 1 0 0
TCP 10.96.0.10:53 rr
-> 10.244.0.2:53 Masq 1 0 0
-> 10.244.0.3:53 Masq 1 0 0
TCP 10.96.0.10:9153 rr
-> 10.244.0.2:9153 Masq 1 0 0
-> 10.244.0.3:9153 Masq 1 0 0
TCP 10.102.176.227:80 rr
-> 10.244.1.4:80 Masq 1 0 0
-> 10.244.2.2:80 Masq 1 0 0
-> 10.244.3.4:80 Masq 1 0 0
UDP 10.96.0.10:53 rr
-> 10.244.0.2:53 Masq 1 0 0
-> 10.244.0.3:53 Masq 1 0 0 四、ConfigMap操作
1）列出configmap资源（kebu-system名称空间下）
Copy $ kubectl get cm -n kube-system
NAME DATA AGE
coredns 1 3d23h
extension-apiserver-authentication 6 3d23h
kube-flannel-cfg 2 3d15h
kube-proxy 2 3d23h
kubeadm-config 2 3d23h
kubelet-config-1.18 1 3d23h 2）修改kube-proxy
kubectl edit cm kube-proxy -n kube-system
-n kube-system为指定名称空间。
修改完kube-proxy，需要删除并重新生成kube-system下的对应6个kube-proxy的pod（由于这里测试用的主节点+工作节点有6个）。
实现批量删除，通过labels：
Copy $ kubectl get pods -n kube-system --show-labels
NAME READY STATUS RESTARTS AGE LABELS
coredns-7ff77c879f-7t8nw 1/1 Running 0 3d23h k8s-app=kube-dns,pod-template-hash=7ff77c879f
coredns-7ff77c879f-bpkwh 1/1 Running 0 3d23h k8s-app=kube-dns,pod-template-hash=7ff77c879f
etcd-31 1/1 Running 2 3d23h component=etcd,tier=control-plane
etcd-32 1/1 Running 0 2d14h component=etcd,tier=control-plane
etcd-33 1/1 Running 0 2d14h component=etcd,tier=control-plane
kube-apiserver-31 1/1 Running 2 3d23h component=kube-apiserver,tier=control-plane
kube-apiserver-32 1/1 Running 0 2d14h component=kube-apiserver,tier=control-plane
kube-apiserver-33 1/1 Running 0 2d14h component=kube-apiserver,tier=control-plane
kube-controller-manager-31 1/1 Running 3 3d23h component=kube-controller-manager,tier=control-plane
kube-controller-manager-32 1/1 Running 1 2d14h component=kube-controller-manager,tier=control-plane
kube-controller-manager-33 1/1 Running 0 2d14h component=kube-controller-manager,tier=control-plane
kube-flannel-ds-amd64-76cdz 1/1 Running 0 3d15h app=flannel,controller-revision-hash=56c5465959,pod-template-generation=1,tier=node
kube-flannel-ds-amd64-ct8v2 1/1 Running 0 2d17h app=flannel,controller-revision-hash=56c5465959,pod-template-generation=1,tier=node
kube-flannel-ds-amd64-h6m9w 1/1 Running 0 2d17h app=flannel,controller-revision-hash=56c5465959,pod-template-generation=1,tier=node
kube-flannel-ds-amd64-l6rfc 1/1 Running 0 2d14h app=flannel,controller-revision-hash=56c5465959,pod-template-generation=1,tier=node
kube-flannel-ds-amd64-nm5rl 1/1 Running 0 2d17h app=flannel,controller-revision-hash=56c5465959,pod-template-generation=1,tier=node
kube-flannel-ds-amd64-qlv78 1/1 Running 0 2d14h app=flannel,controller-revision-hash=56c5465959,pod-template-generation=1,tier=node
kube-proxy-27226 1/1 Running 0 2d14h controller-revision-hash=55877fc8b6,k8s-app=kube-proxy,pod-template-generation=1
kube-proxy-5qmnq 1/1 Running 0 2d17h controller-revision-hash=55877fc8b6,k8s-app=kube-proxy,pod-template-generation=1
kube-proxy-79vk2 1/1 Running 0 2d17h controller-revision-hash=55877fc8b6,k8s-app=kube-proxy,pod-template-generation=1
kube-proxy-hwfss 1/1 Running 2 3d23h controller-revision-hash=55877fc8b6,k8s-app=kube-proxy,pod-template-generation=1
kube-proxy-ms2lx 1/1 Running 0 2d17h controller-revision-hash=55877fc8b6,k8s-app=kube-proxy,pod-template-generation=1
kube-proxy-z68st 1/1 Running 0 2d14h controller-revision-hash=55877fc8b6,k8s-app=kube-proxy,pod-template-generation=1
kube-scheduler-31 1/1 Running 4 3d23h component=kube-scheduler,tier=control-plane
kube-scheduler-32 1/1 Running 0 2d14h component=kube-scheduler,tier=control-plane
kube-scheduler-33 1/1 Running 1 2d14h component=kube-scheduler,tier=control-plane 看到这6个pod都具有同一个label叫k8s-app=kube-proxy, 所以如2-2的操作，批量删除加入label后的指令是：
kubectl delete pods -l k8s-app=kube-proxy -n kube-system
kube-proxy的pod被删除后重新根据修改后的配置清单生成新的pod。
五、deployments/rc/rs删除操作
上面测试用的两个pod，如果直接使用kubectl delete pod来删除，过一会又会生成新的pod，原因是对应的pod在创建时，kubernetes创建了对应的deployment和rs（副本集replicasets）来监控pod的生命周期。所以，要删除这两个pod，首先要删除对应的deployment/rc/rs。
检查是否创建了deployments任务：kubectl get deployments
检查是否创建了副本控制器ReplicationController：kubectl get rc
检查死否创建了副本集replicasets：kubectl get rs
删除对应的对应的deployment：kubectl delete deployment test1
