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- 预先创建相关pv
[root@k8s-master cka]# cat pv-5g.yaml kind: PersistentVolume apiVersion: v1 metadata: name: task-pv-volume-5g labels: type: local spec: storageClassName: manual capacity: storage: 5Gi accessModes: - ReadWriteOnce hostPath: path: "/root/cka/data" [root@k8s-master cka]# cat pv.yaml kind: PersistentVolume apiVersion: v1 metadata: name: task-pv-volume labels: type: local spec: storageClassName: manual capacity: storage: 2Gi accessModes: - ReadWriteOnce hostPath: path: "/root/cka/data" - 执行以下yaml，创建headless servcie，statefulset，系统从statefulset模板中自动创建pvc
[root@k8s-master cka]# cat statefulset.yaml apiVersion: v1 kind: Service metadata: name: nginx-stateful labels: app: nginx-stateful spec: ports: - port: 80 name: web clusterIP: None selector: appstateful: nginx <<<<这里要等于statefulset中的spec.selector.matchLabels和spec.template.metadata.labels --- apiVersion: apps/v1 kind: StatefulSet metadata: name: web spec: selector: matchLabels: appstateful: nginx # has to match .spec.template.metadata.labels serviceName: "nginx-stateful" replicas: 2 # by default is 1 template: metadata: labels: appstateful: nginx # has to match .spec.selector.matchLabels 应用到所有pods上 spec: terminationGracePeriodSeconds: 10 containers: - name: nginx image: nginx ports: - containerPort: 80 name: web volumeMounts: - name: www mountPath: /usr/share/nginx/html volumeClaimTemplates: - metadata: name: www spec: accessModes: [ "ReadWriteOnce" ] storageClassName: manual resources: requests: storage: 1Gi - 产生的输出效果
[root@k8s-master cka]# kubectl get statefulset web -o yaml apiVersion: apps/v1 kind: StatefulSet metadata: annotations: kubectl.kubernetes.io/last-applied-configuration: | {"apiVersion":"apps/v1","kind":"StatefulSet","metadata":{"annotations":{},"name":"web","namespace":"default"},"spec":{"replicas":2,"selector":{"matchLabels":{"appstateful":"nginx"}},"serviceName":"nginx-stateful","template":{"metadata":{"labels":{"appstateful":"nginx"}},"spec":{"containers":[{"image":"nginx","name":"nginx","ports":[{"containerPort":80,"name":"web"}],"volumeMounts":[{"mountPath":"/usr/share/nginx/html","name":"www"}]}],"terminationGracePeriodSeconds":10}},"volumeClaimTemplates":[{"metadata":{"name":"www"},"spec":{"accessModes":["ReadWriteOnce"],"resources":{"requests":{"storage":"1Gi"}},"storageClassName":"manual"}}]}} creationTimestamp: 2018-08-09T10:22:45Z generation: 5 name: web namespace: default resourceVersion: "245069" selfLink: /apis/apps/v1/namespaces/default/statefulsets/web uid: 282abb71-9bbe-11e8-a2f9-000c29850765 spec: podManagementPolicy: OrderedReady <<<如果是Parallel 则会同时启动删除pod而不按照强制顺序 replicas: 2 revisionHistoryLimit: 10 selector: matchLabels: appstateful: nginx serviceName: nginx-stateful template: metadata: creationTimestamp: null labels: appstateful: nginx spec: containers: - image: nginx imagePullPolicy: Always name: nginx ports: - containerPort: 80 name: web protocol: TCP resources: {} terminationMessagePath: /dev/termination-log terminationMessagePolicy: File volumeMounts: - mountPath: /usr/share/nginx/html name: www dnsPolicy: ClusterFirst restartPolicy: Always schedulerName: default-scheduler securityContext: {} terminationGracePeriodSeconds: 10 updateStrategy: rollingUpdate: partition: 0 <<<<<分区rollingupdate，pod编号大于等于这个数字的会被update，小于的不变。等于可以做到灰度发布 type: RollingUpdate volumeClaimTemplates: - metadata: creationTimestamp: null name: www spec: accessModes: - ReadWriteOnce resources: requests: storage: 1Gi storageClassName: manual status: phase: Pending status: collisionCount: 0 currentReplicas: 2 currentRevision: web-7b4ff57f55 observedGeneration: 5 readyReplicas: 2 replicas: 2 updateRevision: web-7b4ff57f55[root@k8s-master cka]# kubectl get svc -o wide NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR kubernetes ClusterIP 10.250.0.1 <none> 443/TCP 3d <none> nginx ClusterIP 10.250.0.157 <none> 80/TCP 7h app=nginx nginx-stateful ClusterIP None <none> 80/TCP 16m appstateful=nginx
[root@k8s-master cka]# kubectl get statefulset -o wide NAME DESIRED CURRENT AGE CONTAINERS IMAGES web 2 2 16m nginx nginx
[root@k8s-master cka]# kubectl get pods -o wide NAME READY STATUS RESTARTS AGE IP NODE busybox-6cdcdb6f5f-tfh84 1/1 Running 54 3d 10.244.0.4 k8s-master mysql 1/1 Running 0 1d 10.244.1.23 k8s-node1 nginx-56f766d96f-96vx7 1/1 Running 0 7h 10.244.1.24 k8s-node1 nginx-56f766d96f-ckxqj 1/1 Running 0 7h 10.244.0.9 k8s-master pi 0/1 Completed 0 2d 10.244.1.8 k8s-node1 pi-jkdfw 0/1 Completed 0 1d 10.244.1.14 k8s-node1 redis 1/1 Running 0 1d 10.244.1.19 k8s-node1 static-web-k8s-master 1/1 Running 0 3h 10.244.0.10 k8s-master web-0 1/1 Running 0 17m 10.244.1.25 k8s-node1 web-1 1/1 Running 0 17m 10.244.0.11 k8s-master
[root@k8s-master cka]# kubectl get pvc -o wide NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE task-pv-claim Terminating task-pv-volume-4g 4Gi RWO manual 1d www-web-0 Bound task-pv-volume 2Gi RWO manual 18m www-web-1 Bound task-pv-volume-5g 5Gi RWO manual 18m
- dns解析
[root@k8s-master cka]# kubectl exec -it busybox-6cdcdb6f5f-tfh84 sh / # nslookup web-0.nginx-stateful.default.svc.cluster.local Server: 10.250.0.53 Address 1: 10.250.0.53 Name: web-0.nginx-stateful.default.svc.cluster.local Address 1: 10.244.1.25 / # nslookup web-1.nginx-stateful.default.svc.cluster.local Server: 10.250.0.53 Address 1: 10.250.0.53 Name: web-1.nginx-stateful.default.svc.cluster.local Address 1: 10.244.0.11
解析svc域名，直接解析出两个pod的ip
/ # nslookup nginx-stateful.default.svc.cluster.local Server: 10.250.0.53 Address 1: 10.250.0.53 Name: nginx-stateful.default.svc.cluster.local Address 1: 10.244.0.11 Address 2: 10.244.1.25
修改image，产生rollingupdate：
web-0 1/1 Running 0 52m web-1 1/1 Running 0 14m -------------开始rolling----- web-1 1/1 Terminating 0 14m web-1 0/1 Terminating 0 14m web-1 0/1 Terminating 0 15m web-1 0/1 Terminating 0 15m web-1 0/1 Pending 0 0s web-1 0/1 Pending 0 0s web-1 0/1 ContainerCreating 0 0s web-1 0/1 ContainerCreating 0 1s web-1 0/1 ContainerCreating 0 6s web-1 1/1 Running 0 15s ------以上终结web-1 pod,并重新启动一个新web-1 pod，成功后开始web0---- web-0 1/1 Terminating 0 53m web-0 0/1 Terminating 0 53m web-0 0/1 Terminating 0 53m web-0 0/1 Terminating 0 53m web-0 0/1 Pending 0 0s web-0 0/1 Pending 0 0s web-0 0/1 ContainerCreating 0 2s web-0 0/1 ContainerCreating 0 4s web-0 0/1 ContainerCreating 0 10s web-0 1/1 Running 0 34s ------以上web0终结及重启过程------------
- [root@k8s-master cka]# kubectl patch statefulset web -p '{"spec":{"replicas":1}}'
减少replicas，将从pod名字中数字编号最大的开始减。且被删除pod所用的pvc并不会被删除，必须手工干预。如果不删除这些pvc，则如果replicas恢复回来，对应的pod名字还会claim对应的pvc，这样保持一致。Note that, the PersistentVolumes associated with the Pods’ PersistentVolume Claims are not deleted when the Pods, or StatefulSet are deleted. This must be done manually.
Statefulset:
pod的名字按照 {statefulset名字}-{数字从0排序}，名字始终稳定，不论怎么扩展删除
自动按模板产生pvc， pvc名字 {pvc模板名}-{statefulset名}-{从0编号}，pod与pvc关联关系始终稳定不变
按顺序产生pod，按反序删除pod。
rollingupdate时候安装类似删除的动作，删一个，起一个。
https://v1-10.docs.kubernetes.io/docs/concepts/workloads/controllers/statefulset/
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