容器云平台No.3~kubernetes简单使用
scofield 菜鸟运维杂谈
今天是是第三篇，接着上一篇继续
首先，通过kubectl可以看到,三个节点都正常运行
1[root@k8s-master001 ~]# kubectl get no
2NAME STATUS ROLES AGE VERSION
3k8s-master001 Ready master 16h v1.19.0
4k8s-master002 Ready master 16h v1.19.0
5k8s-master003 Ready master 16h v1.19.0现在来部署第一个服务，这里以nginx为例
1[root@k8s-master001 ~]# kubectl run nginx --image=nginx --port=80
2pod/nginx created可以看到，我们在k8s集群上创建了一个nginx应用，然后我们通过如下命令查看状态，发现现在nginx状态为Pending
1[root@k8s-master001 ~]# kubectl get po
2NAME READY STATUS RESTARTS AGE
3nginx 0/1 Pending 0 7s现在我们使用kubectl describe命令来查看更多信息
1[root@k8s-master001 ~]# kubectl describe po nginx
2Name: nginx
3Namespace: default
4Priority: 0
5Node: <none>
6Labels: run=nginx
7Annotations: <none>
8Status: Pending
9IP:
10IPs: <none>
11Containers:
12 nginx:
13 Image: nginx
14 Port: <none>
15 Host Port: <none>
16 Environment: <none>
17 Mounts:
18 /var/run/secrets/kubernetes.io/serviceaccount from default-token-6gd92 (ro)
19Conditions:
20 Type Status
21 PodScheduled False
22Volumes:
23 default-token-6gd92:
24 Type: Secret (a volume populated by a Secret)
25 SecretName: default-token-6gd92
26 Optional: false
27QoS Class: BestEffort
28Node-Selectors: <none>
29Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
30 node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
31Events:
32 Type Reason Age From Message
33 ---- ------ ---- ---- -------
34 Warning FailedScheduling 15s 0/3 nodes are available: 3 node(s) had taint {node-role.kubernetes.io/master: }, that the pod didn't tolerate.
35 Warning FailedScheduling 14s 0/3 nodes are available: 3 node(s) had taint {node-role.kubernetes.io/master: }, that the pod didn't tolerate.从输出信息可以看到最隐藏后两个事件3 node(s) had taint {node-role.kubernetes.io/master: }, that the pod didn't tolerate.
什么意思呢？什么意思呢？
这个提示表示，没有节点可以接受调度。
为什么会这样呢？
因为我们现在三个节点都是master节点，还没有添加node节点。默认情况下，master打了污点（taint，后续再介绍），master节点不接收调度。
由于我们这里是测试环境，没有多余的机器来作为node节点，可以手动删除master的污点，让master节点接收调度。
通过如下命令可以查看taint信息：
1[root@k8s-master001 ~]# kubectl get no -o yaml | grep taint -A 5
2 f:taints: {}
3 manager: kube-controller-manager
4 operation: Update
5 time: "2020-09-10T09:10:40Z"
6 - apiVersion: v1
7 fieldsType: FieldsV1
8--
9 taints:
10 - effect: NoSchedule
11 key: node-role.kubernetes.io/master
12 status:
13 addresses:
14 - address: 10.26.25.20
15--
16 f:taints: {}
17 manager: kube-controller-manager
18 operation: Update
19 time: "2020-09-10T09:30:25Z"
20 - apiVersion: v1
21 fieldsType: FieldsV1
22--
23 taints:
24 - effect: NoSchedule
25 key: node-role.kubernetes.io/master
26 status:
27 addresses:
28 - address: 10.26.25.21
29--
30 f:taints: {}
31 manager: kube-controller-manager
32 operation: Update
33 time: "2020-09-10T09:35:43Z"
34 - apiVersion: v1
35 fieldsType: FieldsV1
36--
37 taints:
38 - effect: NoSchedule
39 key: node-role.kubernetes.io/master
40 status:
41 addresses:
42 - address: 10.26.25.22删除污点node-role.kubernetes.io/master，如下所示
1[root@k8s-master001 ~]# kubectl taint nodes --all node-role.kubernetes.io/master-
2node/k8s-master001 untainted
3node/k8s-master002 untainted
4node/k8s-master003 untainted然后现在在看nginx的状态，已经变为ContainerCreating，这表示已经分配到节点，开始创建nginx的pod了
1[root@k8s-master001 ~]# kubectl get po
2NAME READY STATUS RESTARTS AGE
3nginx 0/1 ContainerCreating 0 3m11s使用kubectl get po -o wide查看，现在nginx已经正常运行了，而且可以看到，nginx现在被分配到 k8s-master001节点上，Pod IP是10.244.0.4
1[root@k8s-master001 ~]# kubectl get po -o wide
2NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
3nginx 1/1 Running 0 56m 10.244.0.4 k8s-master001 <none> <none>现在来访问nginx,熟悉的200出现了~~
1[root@k8s-master001 ~]# curl -I 10.244.0.4
2HTTP/1.1 200 OK
3Server: nginx/1.19.2
4Date: Fri, 11 Sep 2020 02:22:41 GMT
5Content-Type: text/html
6Content-Length: 612
7Last-Modified: Tue, 11 Aug 2020 14:50:35 GMT
8Connection: keep-alive
9ETag: "5f32b03b-264"
10Accept-Ranges: bytes但是如果在非集群节点上访问10.244.0.4，比如在自己的电脑上访问
1[~/b/] : curl -I 10.244.0.42curl: (55) getpeername() failed with errno 22: Invalid argument
现在就来解决这个问题，
1、我们删掉原来创建的nginx pod
1[root@k8s-master001 ~]# kubectl delete po nginx
2pod "nginx" deleted2、创建nginx.yaml文件
1[root@k8s-master001 ~]# cat nginx.yaml
2---
3apiVersion: apps/v1
4kind: StatefulSet
5metadata:
6 name: nginx
7 labels:
8 app: nginx
9spec:
10 serviceName: nginx
11 replicas: 1
12 selector:
13 matchLabels:
14 app: nginx
15 template:
16 metadata:
17 labels:
18 app: nginx
19 spec:
20 terminationGracePeriodSeconds: 180
21 containers:
22 - name: nginx
23 image: nginx
24 imagePullPolicy: Always
25 ports:
26 - containerPort: 80
27 name: port
28---
29apiVersion: v1
30kind: Service
31metadata:
32 name: nginx
33 labels:
34 app: nginx
35spec:
36 type: NodePort
37 ports:
38 - port: 80
39 targetPort: 80
40 selector:
41 app: nginx3、执行kubectl apply -f nginx.yaml部署
1[root@k8s-master001 ~]# kubectl apply -f nginx.yaml
2statefulset.apps/nginx created
3service/nginx created
4
5[root@k8s-master001 ~]# kubectl get po,ep,svc
6NAME READY STATUS RESTARTS AGE
7pod/nginx-0 1/1 Running 0 24s
8
9NAME ENDPOINTS AGE
10endpoints/kubernetes 10.26.25.20:6443,10.26.25.21:6443,10.26.25.22:6443 17h
11endpoints/nginx 10.244.2.3:80 23s
12
13NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
14service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 17h
15service/nginx NodePort 10.106.27.213 <none> 80:30774/TCP 23s现在能看到，创建了一个名为nginx的service，把nginx默认的80端口映射到了30774
访问集群任意节点的IP：32650，这里是10.26.25.20:30774
4、在集群节点上访问：
1[root@k8s-master001 ~]# curl -I 10.26.25.20:30774
2HTTP/1.1 200 OK
3Server: nginx/1.19.2
4Date: Fri, 11 Sep 2020 02:53:55 GMT
5Content-Type: text/html
6Content-Length: 612
7Last-Modified: Tue, 11 Aug 2020 14:50:35 GMT
8Connection: keep-alive
9ETag: "5f32b03b-264"
10Accept-Ranges: bytes5、在笔记本电脑上访问：
1[~/b/wechatimages] : curl -I 10.26.25.20:30774
2HTTP/1.1 200 OK
3Server: nginx/1.19.2
4Date: Fri, 11 Sep 2020 02:54:24 GMT
5Content-Type: text/html
6Content-Length: 612
7Last-Modified: Tue, 11 Aug 2020 14:50:35 GMT
8Connection: keep-alive
9ETag: "5f32b03b-264"
10Accept-Ranges: bytes如果您还是￥@@#￥……%#@
可以先行了解kubernetes的pod,endpoint,service等概念。。。后续文章也会陆续讲到。。。
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