容器云平台No.3~kubernetes使用入门
2020-09-20 本文已影响0人
空壳先生
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
[root@k8s-master001 ~]# kubectl get no
NAME STATUS ROLES AGE VERSION
k8s-master001 Ready master 16h v1.19.0
k8s-master002 Ready master 16h v1.19.0
k8s-master003 Ready master 16h v1.19.0
现在来部署第一个服务，这里以nginx为例
[root@k8s-master001 ~]# kubectl run nginx --image=nginx --port=80
pod/nginx created
可以看到，我们再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
[root@k8s-master001 ~]# kubectl get po
NAME READY STATUS RESTARTS AGE
nginx 0/1 Pending 0 7s
现在我们使用kubectl describe命令来查看更多信息
[root@k8s-master001 ~]# kubectl describe po nginx
Name: nginx
Namespace: default
Priority: 0
Node: <none>
Labels: run=nginx
Annotations: <none>
Status: Pending
IP:
IPs: <none>
Containers:
nginx:
Image: nginx
Port: <none>
Host Port: <none>
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from default-token-6gd92 (ro)
Conditions:
Type Status
PodScheduled False
Volumes:
default-token-6gd92:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-6gd92
Optional: false
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Warning FailedScheduling 15s 0/3 nodes are available: 3 node(s) had taint {node-role.kubernetes.io/master: }, that the pod didn't tolerate.
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：
[root@k8s-master001 ~]# kubectl get no -o yaml | grep taint -A 5
f:taints: {}
manager: kube-controller-manager
operation: Update
time: "2020-09-10T09:10:40Z"
- apiVersion: v1
fieldsType: FieldsV1
--
taints:
- effect: NoSchedule
key: node-role.kubernetes.io/master
status:
addresses:
- address: 10.26.25.20
--
f:taints: {}
manager: kube-controller-manager
operation: Update
time: "2020-09-10T09:30:25Z"
- apiVersion: v1
fieldsType: FieldsV1
--
taints:
- effect: NoSchedule
key: node-role.kubernetes.io/master
status:
addresses:
- address: 10.26.25.21
--
f:taints: {}
manager: kube-controller-manager
operation: Update
time: "2020-09-10T09:35:43Z"
- apiVersion: v1
fieldsType: FieldsV1
--
taints:
- effect: NoSchedule
key: node-role.kubernetes.io/master
status:
addresses:
- address: 10.26.25.22
删除污点node-role.kubernetes.io/master，如下所示
[root@k8s-master001 ~]# kubectl taint nodes --all node-role.kubernetes.io/master-
node/k8s-master001 untainted
node/k8s-master002 untainted
node/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
[root@k8s-master001 ~]# kubectl get po
NAME READY STATUS RESTARTS AGE
nginx 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
[root@k8s-master001 ~]# kubectl get po -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx 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~~
[root@k8s-master001 ~]# curl -I 10.244.0.4
HTTP/1.1 200 OK
Server: nginx/1.19.2
Date: Fri, 11 Sep 2020 02:22:41 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 11 Aug 2020 14:50:35 GMT
Connection: keep-alive
ETag: "5f32b03b-264"
Accept-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
[~/b/] : curl -I 10.244.0.4
curl: (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
[root@k8s-master001 ~]# kubectl delete po nginx
pod "nginx" deleted
2、创建nginx.yaml文件
[root@k8s-master001 ~]# cat nginx.yaml
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: nginx
labels:
app: nginx
spec:
serviceName: nginx
replicas: 1
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
terminationGracePeriodSeconds: 180
containers:
- name: nginx
image: nginx
imagePullPolicy: Always
ports:
- containerPort: 80
name: port
---
apiVersion: v1
kind: Service
metadata:
name: nginx
labels:
app: nginx
spec:
type: NodePort
ports:
- port: 80
targetPort: 80
selector:
app: nginx
3、执行kubectl apply -f nginx.yaml部署
[root@k8s-master001 ~]# kubectl apply -f nginx.yaml
statefulset.apps/nginx created
service/nginx created
[root@k8s-master001 ~]# kubectl get po,ep,svc
NAME READY STATUS RESTARTS AGE
pod/nginx-0 1/1 Running 0 24s
NAME ENDPOINTS AGE
endpoints/kubernetes 10.26.25.20:6443,10.26.25.21:6443,10.26.25.22:6443 17h
endpoints/nginx 10.244.2.3:80 23s
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 17h
service/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
在集群节点上访问：
[root@k8s-master001 ~]# curl -I 10.26.25.20:30774
HTTP/1.1 200 OK
Server: nginx/1.19.2
Date: Fri, 11 Sep 2020 02:53:55 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 11 Aug 2020 14:50:35 GMT
Connection: keep-alive
ETag: "5f32b03b-264"
Accept-Ranges: bytes
在笔记本电脑上访问：
[~/b/wechatimages] : curl -I 10.26.25.20:30774
HTTP/1.1 200 OK
Server: nginx/1.19.2
Date: Fri, 11 Sep 2020 02:54:24 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 11 Aug 2020 14:50:35 GMT
Connection: keep-alive
ETag: "5f32b03b-264"
Accept-Ranges: bytes
如果还是不太理解这些概念，可以先行了解kubernetes的pod,endpoint,service等概念。。。后续文章也会陆续讲到。。。
