K8S 入门练习
一、启动pod
1. 手动启动
apiVersion: v1 kind: Pod metadata: name: nginx-test labels: app: nginx-test spec: containers: - name: nginx image: nginx imagePullPolicy: IfNotPresent ########优先使用本地docker image，如果找不到了，再去网上下载 ports: - containerPort: 80
2. 用rs启动
apiVersion: apps/v1 kind: ReplicaSet metadata: name: nginx-test spec: replicas: 2 selector: matchLabels: tier: nginx-test template: metadata: labels: tier: nginx-test spec: containers: - name: nginx image: nginx imagePullPolicy: IfNotPresent env: - name: Get_HOSTS_FROM value: dns ports: - containerPort: 80
二、配置svc
1. 配置deployment，管理pod
apiVersion: apps/v1 kind: Deployment metadata: # deployment名字 name: nginx-deployment spec: replicas: 1 selector: matchLabels: app: nginx-test # 定义Pod的模板 template: metadata: labels: app: nginx-test spec: containers: - name: nginx image: nginx imagePullPolicy: IfNotPresent ports: - containerPort: 80
root@master:~# kubectl get deployments NAME READY UP-TO-DATE AVAILABLE AGE nginx-deployment 1/1 1 1 31m
2. 配置svc，关联pod
apiVersion: v1 kind: Service metadata: name: nginx labels: app: nginx-test spec: ports: - port: 80 targetPort: 8080 selector: app: nginx-test
root@master:~# k get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 51d nginx ClusterIP 10.111.79.179 <none> 8080/TCP 29m
root@master:~# curl 10.111.79.179:8080 <!DOCTYPE html> <html> <head> <title>Welcome to nginx!</title> <style> body { width: 35em; margin: 0 auto; font-family: Tahoma, Verdana, Arial, sans-serif; } </style> </head> <body> <h1>Welcome to nginx!</h1> <p>If you see this page, the nginx web server is successfully installed and working. Further configuration is required.</p> <p>For online documentation and support please refer to <a href="http://nginx.org/">nginx.org</a>.<br/> Commercial support is available at <a href="http://nginx.com/">nginx.com</a>.</p> <p><em>Thank you for using nginx.</em></p> </body> </html> root@master:~#
三、pv/pvc 应用
本例中，存储采用hostpath，位于host的/tmp目录
1. pvsmall.yaml
apiVersion: v1 kind: PersistentVolume metadata: name: pvsmall labels: name: pvsmall spec: hostPath: path: "/tmp" accessModes: ["ReadWriteMany","ReadWriteOnce"] capacity: storage: 1Gi
2. pvbig.yaml
apiVersion: v1 kind: PersistentVolume metadata: name: pvbig labels: name: pvbig spec: hostPath: path: "/tmp" accessModes: ["ReadWriteOnce"] capacity: storage: 2Gi
3. pvc2g.yaml
apiVersion: v1 kind: PersistentVolumeClaim metadata: name: pvc2g namespace: default spec: accessModes: ["ReadWriteOnce"] resources: requests: storage: 2Gi
4. create pvsmall,pvbig,pvc2g
root@master:/root/pv# kubectl create -f pvsmall.yaml persistentvolume/pvsmall created root@master:/root/pv# kubectl create -f pvbig.yaml persistentvolume/pvbig created root@master:/root/pv# kubectl create -f pvc2g.yaml persistentvolumeclaim/pvc2g created root@master:/root/pv# kubectl get pv,pvc NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE persistentvolume/pvbig 2Gi RWO Retain Bound default/pvc2g 10s persistentvolume/pvsmall 1Gi RWO,RWX Retain Available 15s NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE persistentvolumeclaim/pvc2g Bound pvbig 2Gi RWO 8s root@master:/root/pv#
2g的pvc claim，会选到2g的pv上，1g不满足
5. create deployment
apiVersion: apps/v1 kind: Deployment metadata: name: nginx-deployment spec: replicas: 1 selector: matchLabels: app: nginx-test # 定义Pod的模板 template: metadata: labels: app: nginx-test spec: containers: - name: nginx image: nginx imagePullPolicy: IfNotPresent ports: - containerPort: 80 volumeMounts: - name: www mountPath: /usr/share/nginx/html volumes: - name: www persistentVolumeClaim: claimName: pvc2g
root@master:/root/pv# kubectl create -f deployment.yaml deployment.apps/nginx-deployment created root@master:/root/pv# kubectl get deployments NAME READY UP-TO-DATE AVAILABLE AGE nginx-deployment 1/1 1 1 6s root@master:/root/pv#
6. check下pv是否生效
root@master:/root/pv# kubectl get deployments NAME READY UP-TO-DATE AVAILABLE AGE nginx-deployment 1/1 1 1 103s root@master:/root/pv# kubectl get pods NAME READY STATUS RESTARTS AGE busybox 1/1 Running 2 123m nginx-deployment-596c45ccf8-ccslm 1/1 Running 0 104s root@master:/root/pv# kubectl exec -it nginx-deployment-596c45ccf8-ccslm -- /bin/bash root@nginx-deployment-596c45ccf8-ccslm:/# ls /usr/share/nginx/html/ systemd-private-2996b7aae3b7456fa565724b9f07ed3f-systemd-timesyncd.service-79oY1P test313 root@nginx-deployment-596c45ccf8-ccslm:/#
可以看到，/tmp 目录挂载到了容器里的，/usr/share/nginx/html下面。
四、pvc删除后，pv回收复用
解决办法： 手动修改该pv
1. pvc删除后
root@master:/root/pv# k get pv NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE pvbig 2Gi RWO Retain Released default/pvc2g 38m pvsmall 1Gi RWO,RWX Retain Available 39m root@master:/root/pv#
2. 此时pv为Released，并不是Available，所以还无法复用
root@master:/root/pv# kubectl get pv pvbig -o json { "apiVersion": "v1", "kind": "PersistentVolume", "metadata": { "annotations": { "pv.kubernetes.io/bound-by-controller": "yes" }, "creationTimestamp": "2021-03-13T11:44:23Z", "finalizers": [ "kubernetes.io/pv-protection" ], "labels": { "name": "pvbig" }, "managedFields": [ { "apiVersion": "v1", "fieldsType": "FieldsV1", "fieldsV1": { "f:metadata": { "f:labels": { ".": {}, "f:name": {} } }, "f:spec": { "f:accessModes": {}, "f:capacity": { ".": {}, "f:storage": {} }, "f:hostPath": { ".": {}, "f:path": {}, "f:type": {} }, "f:persistentVolumeReclaimPolicy": {}, "f:volumeMode": {} } }, "manager": "kubectl", "operation": "Update", "time": "2021-03-13T11:44:23Z" }, { "apiVersion": "v1", "fieldsType": "FieldsV1", "fieldsV1": { "f:metadata": { "f:annotations": { ".": {}, "f:pv.kubernetes.io/bound-by-controller": {} } }, "f:spec": { "f:claimRef": { ".": {}, "f:apiVersion": {}, "f:kind": {}, "f:name": {}, "f:namespace": {}, "f:resourceVersion": {}, "f:uid": {} } }, "f:status": { "f:phase": {} } }, "manager": "kube-controller-manager", "operation": "Update", "time": "2021-03-13T12:23:17Z" } ], "name": "pvbig", "resourceVersion": "495927", "selfLink": "/api/v1/persistentvolumes/pvbig", "uid": "23c556b0-9e5f-4c8b-be5a-30811f18f99f" }, "spec": { "accessModes": [ "ReadWriteOnce" ], "capacity": { "storage": "2Gi" }, "claimRef": { "apiVersion": "v1", "kind": "PersistentVolumeClaim", "name": "pvc2g", "namespace": "default", "resourceVersion": "490273", "uid": "c769a790-40bd-4d09-860f-7cee90302910" }, "hostPath": { "path": "/tmp", "type": "" }, "persistentVolumeReclaimPolicy": "Retain", "volumeMode": "Filesystem" }, "status": { "phase": "Released" } }
删除红框部分：
3. 删除后
root@master:/root/pv# kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
pvbig 2Gi RWO Retain Available 47m
pvsmall 1Gi RWO,RWX Retain Available 47m
root@master:/root/pv#
此时pv为Available状态，可用。
四、kubectl 端口妆发
1. 配置nginx pod
root@master:/root/nginx# k get pods -owide NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES busybox 1/1 Running 2 168m 192.168.166.137 node1 <none> <none> nginx-test 1/1 Running 0 6s 192.168.104.23 node2 <none> <none>
2. master上curl
root@master:/root/nginx# curl 192.168.104.23:80 <!DOCTYPE html> <html> <head> <title>Welcome to nginx!</title> <style> body { width: 35em; margin: 0 auto; font-family: Tahoma, Verdana, Arial, sans-serif; } </style> </head> <body> <h1>Welcome to nginx!</h1> <p>If you see this page, the nginx web server is successfully installed and working. Further configuration is required.</p> <p>For online documentation and support please refer to <a href="http://nginx.org/">nginx.org</a>.<br/> Commercial support is available at <a href="http://nginx.com/">nginx.com</a>.</p> <p><em>Thank you for using nginx.</em></p> </body> </html>
3. 做端口转发
root@master:/root/nginx# kubectl port-forward nginx-test 8080:80 Forwarding from 127.0.0.1:8080 -> 80 Forwarding from [::1]:8080 -> 80
默认只在本地转发，如果想0.0.0.0
root@master:/root/nginx# kubectl port-forward nginx-test --address 0.0.0.0 8080:80 Forwarding from 0.0.0.0:8080 -> 80
