kubectl describe node k8s-node1 獲取節點的詳細信息
kubectl run --help 根據鏡像創建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 查看詳細的信息
刪除創建的POD
kubectl delete pods nginx-deploy-5b66f76f68-hcmb5
創建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
然后在節點上訪問
[root@k8s-node1 ~]# curl 10.109.2.190

Welcome to nginx!

驗證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 測試，下面是幾種測試方法：
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

擴展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
升級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
回滾之前的版本
[root@k8s-master ~]# kubectl rollout undo deployment myapp
deployment.extensions/myapp rolled back

刪除部署的資源：

[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.

遇到的問題1

各節點上配置防火墻
iptables -I INPUT -p tcp -m tcp --dport 10250 -j ACCEPT
-L -vn|more會看到INPUT的reject-with icmp-host-prohibited計數一直在增加。
10250是kubectl exec使用的，不加會報“Error from server: error dialing backend:
dial tcp 192.168.128.164:10250: getsockopt: no route to host”。
遇到的問題2
解決flannel下pod及容器無法跨主機互通問題
flaaner 網絡默認采用vxlan 類型，這種類型默認用的是UDP 協議發包，所以要看防火墻里面是否DROP 了UDP 協議，最簡單的方法是
iptables -P INPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -F
iptables -L -n
然后重啟各節點服務，或者直接重啟各節點的系統

總結

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