k8s常用命令整理

我会带着你远行 2023-10-05 19:09 10阅读 0赞

kubectl describe node k8s-node1 获取节点的详细信息  
kubectl run --help 根据镜像创建POD副本  
kubectl run nginx-deploy --image=nginx --port=80 --replicas=1  
kubectl get pods -o wide  
\[root@k8s-master ~\]\# kubectl get pods -o wide  
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES  
nginx-deploy-5b66f76f68-hcmb5 1/1 Running 0 43s 10.244.2.2 k8s-node1  
kubectl describe pod nginx-deploy-5b66f76f68-hcmb5 查看详细的信息  
删除创建的POD  
kubectl delete pods nginx-deploy-5b66f76f68-hcmb5  
创建server  
\[root@k8s-master ~\]\# kubectl expose deployment nginx-deploy --name=nginx --port 80 --target-port 80 --protocol=TCP  
service/nginx exposed  
\[root@k8s-master ~\]\# kubectl get svc  
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE  
kubernetes ClusterIP 10.96.0.1 443/TCP 3d6h  
nginx ClusterIP 10.109.2.190 80/TCP 12s  
然后在节点上访问  
\[root@k8s-node1 ~\]\# curl 10.109.2.190

Welcome to nginx!

验证dns

root@k8s-master ~\]\# kubectl get svc -n kube-system -o wide  
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR  
kube-dns ClusterIP 10.96.0.10 53/UDP,53/TCP 37d k8s-app=kube-dns  
\[root@k8s-master ~\]\# dig -t A nginx.default.svc.cluster.local @10.96.0.10  
; <<>> DiG 9.9.4-RedHat-9.9.4-73.el7\_6 <<>> -t A nginx.default.svc.cluster.local @10.96.0.10  
;; global options: +cmd

;; Got answer:  
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 29269  
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0  
;; QUESTION SECTION:  
;nginx.default.svc.cluster.local. IN A  
;; ANSWER SECTION:  
nginx.default.svc.cluster.local. 5 IN A 10.105.255.114  
;; Query time: 1 msec  
;; SERVER: 10.96.0.10\#53(10.96.0.10)  
;; WHEN: 一 4月 22 14:58:41 CST 2019  
;; MSG SIZE rcvd: 96  
用POD 测试，下面是几种测试方法：  
kubectl run client --image=busybox -it --restart=Never  
If you don’t see a command prompt, try pressing enter.  
/ \# cat /etc/resolv.conf  
nameserver 10.96.0.10  
search default.svc.cluster.local svc.cluster.local cluster.local localdomain  
options ndots:5  
/\#wget -O - -q http://nginx/  
kubectl exec -it pod-client – nslookup nginx

或者 kubectl exec -it pod-client nslookup nginx  
Server: 10.96.0.10  
Address: 10.96.0.10:53  
Name: nginx.default.svc.cluster.local  
Address: 10.96.174.96  
\*\*\* Can’t find nginx.svc.cluster.local: No answer  
\*\*\* Can’t find nginx.cluster.local: No answer  
\*\*\* Can’t find nginx.localdomain: No answer  
\*\*\* Can’t find nginx.default.svc.cluster.local: No answer  
\*\*\* Can’t find nginx.svc.cluster.local: No answer  
\*\*\* Can’t find nginx.cluster.local: No answer  
\*\*\* Can’t find nginx.localdomain: No answer  
kubectl exec -it pod-client – /bin/sh

扩展POD  
\[root@k8s-master ~\]\# kubectl scale --replicas=5 deployment myapp  
deployment.extensions/myapp scaled  
\[root@k8s-master ~\]\# kubectl get svc  
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE  
kubernetes ClusterIP 10.96.0.1 443/TCP 37d  
nginx ClusterIP 10.110.209.132 80/TCP 11m  
\[root@k8s-master ~\]\# kubectl get pods  
NAME READY STATUS RESTARTS AGE  
client 1/1 Running 0 2m26s  
myapp-9b4987d5-2fb8c 1/1 Running 0 8s  
myapp-9b4987d5-2h8gm 1/1 Running 0 8s  
myapp-9b4987d5-gth7v 1/1 Running 0 8s  
myapp-9b4987d5-tn2q4 1/1 Running 0 4m22s  
myapp-9b4987d5-vsq6h 1/1 Running 0 4m22s  
nginx-deploy-5b66f76f68-lv66h 1/1 Running 2 33d  
升级POD程序  
\[root@k8s-master ~\]\# kubectl set image deployment myapp myapp=ikubernetes/myapp:v2  
deployment.extensions/myapp image updated  
\[root@k8s-master ~\]\# kubectl rollout status deployment myapp  
deployment “myapp” successfully rolled out  
root@k8s-master ~\]\# kubectl get pods  
NAME READY STATUS RESTARTS AGE  
client 1/1 Running 0 7m38s  
myapp-65899575cd-g4jpv 1/1 Running 0 98s  
myapp-65899575cd-jcsqh 1/1 Running 0 104s  
myapp-65899575cd-p6zww 1/1 Running 0 104s  
myapp-65899575cd-rq6lk 1/1 Running 0 99s  
myapp-65899575cd-td87v 1/1 Running 0 104s  
nginx-deploy-5b66f76f68-lv66h 1/1 Running 2 33d  
pod-client 0/1 Error 0 18m

\[root@k8s-master ~\]\# kubectl describe pods myapp-65899575cd-g4jpv

Name: myapp-65899575cd-g4jpv

Namespace: default  
Priority: 0  
PriorityClassName:  
Node: k8s-node1/10.211.55.12  
Start Time: Mon, 22 Apr 2019 16:30:52 +0800  
Labels: pod-template-hash=65899575cd  
run=myapp  
Annotations:  
Status: Running  
IP: 10.244.2.14  
Controlled By: ReplicaSet/myapp-65899575cd  
Containers:  
myapp:  
Container ID: docker://e728c453b29e44bfb4e88c0285cd870f00c8d5bc4bc20daef916a98a7418e8ef  
Image: ikubernetes/myapp:v2  
Image ID: docker-pullable://ikubernetes/myapp@sha256:85a2b81a62f09a414ea33b74fb8aa686ed9b168294b26b4c819df0be0712d358  
Port:  
Host Port:  
State: Running  
Started: Mon, 22 Apr 2019 16:30:53 +0800  
Ready: True  
Restart Count: 0  
Environment:  
Mounts:  
/var/run/secrets/kubernetes.io/serviceaccount from default-token-zzm2j (ro)  
Conditions:  
Type Status  
Initialized True  
Ready True  
ContainersReady True  
PodScheduled True  
Volumes:  
default-token-zzm2j:  
Type: Secret (a volume populated by a Secret)  
SecretName: default-token-zzm2j  
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 Pulled 2m53s kubelet, k8s-node1 Container image “ikubernetes/myapp:v2” already present on machine  
Normal Created 2m52s kubelet, k8s-node1 Created container  
Normal Started 2m52s kubelet, k8s-node1 Started container  
Normal Scheduled 2m52s default-scheduler Successfully assigned default/myapp-65899575cd-g4jpv to k8s-node1  
回滚之前的版本  
\[root@k8s-master ~\]\# kubectl rollout undo deployment myapp  
deployment.extensions/myapp rolled back

删除部署的资源：

\[root@k8s-master ~\]\# kubectl get deploy -o wide  
NAME READY UP-TO-DATE AVAILABLE AGE CONTAINERS IMAGES SELECTOR  
myapp 5/5 5 5 28h myapp ikubernetes/myapp:v1 run=myapp  
nginx-deploy 1/1 1 1 35d nginx-deploy nginx run=nginx-deploy  
\[root@k8s-master ~\]\# kubectl delete deploy myapp  
deployment.extensions “myapp” deleted  
\[root@k8s-master ~\]\# kubectl delete deploy nginx-deploy  
deployment.extensions “nginx-deploy” deleted  
\[root@k8s-master ~\]\# kubectl get deploy -o wide  
No resources found.

遇到的问题1

各节点上配置防火墙  
iptables -I INPUT -p tcp -m tcp --dport 10250 -j ACCEPT  
\-L -vn|more会看到INPUT的reject-with icmp-host-prohibited计数一直在增加。  
10250是kubectl exec使用的，不加会报“Error from server: error dialing backend:  
dial tcp 192.168.128.164:10250: getsockopt: no route to host”。  
遇到的问题2  
解决flannel下pod及容器无法跨主机互通问题  
flaaner 网络默认采用vxlan 类型，这种类型默认用的是UDP 协议发包，所以要看防火墙里面是否DROP 了UDP 协议，最简单的方法是  
iptables -P INPUT ACCEPT  
iptables -P FORWARD ACCEPT  
iptables -F  
iptables -L -n  
然后重启各节点服务，或者直接重启各节点的系统