PetSet—>StatefulSet
特点：
1、稳定且唯一的网络标识符
2、稳定且持久的存储
3、有序、平滑的部署和扩展
4、有序、平滑的删除和终止
5、有序的滚动更新
三个组件：headless,service,StatefulSet,volumeClaimTemplate

sts-pod示例：

  1. [root@master sts]# cat sts-pod.yaml 
  2. apiVersion: v1
  3. kind: Service
  4. metadata:
  5.   name: myapp
  6.   labels:
  7.     app: myapp
  8. spec:
  9.   ports:
  10.   - port: 80
  11.     name: web
  12.   clusterIP: None
  13.   selector:
  14.     app: myapp-pod
  15. ---
  16. apiVersion: apps/v1
  17. kind: StatefulSet
  18. metadata:
  19.   name: myapp
  20. spec:
  21.   serviceName: myapp
  22.   replicas: 3
  23.   selector:
  24.     matchLabels:
  25.       app: myapp-pod
  26.   template:
  27.     metadata:
  28.       labels: 
  29.         app: myapp-pod
  30.     spec:
  31.       containers:
  32.       - name: myapp
  33.         image: ikubernetes/myapp:v1
  34.         ports:
  35.         - name: web
  36.           containerPort: 80
  37.         volumeMounts:
  38.         - name: myappdata
  39.           mountPath: /usr/share/nginx/html
  40.   volumeClaimTemplates:
  41.   - metadata:
  42.       name: myappdata
  43.     spec:
  44.       accessModes: ["ReadWriteOnce"]
  45.       resources:
  46.         requests:
  47.           storage: 5Gi
  48. 查看sts的pod
  49. [root@master sts]# kubectl get pod
  50. NAME      READY   STATUS    RESTARTS   AGE
  51. myapp-0   1/1     Running   0          38m
  52. myapp-1   1/1     Running   0          38m
  53. myapp-2   1/1     Running   0          38m
  54. 查看pv
  55. [root@master sts]# kubectl get pv
  56. NAME    CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM                       STORAGECLASS   REASON   AGE
  57. pv001   5Gi        RWO,RWX        Retain           Bound       default/myappdata-myapp-1                           2d18h
  58. pv002   5Gi        RWO,RWX        Retain           Bound       default/myappdata-myapp-2                           2d18h
  59. pv003   5Gi        RWO            Retain           Bound       default/myappdata-myapp-0                           2d18h
  60. pv004   8Gi        RWX            Retain           Available                                                       2d18h
  61. pv005   10Gi       RWO,RWX        Retain           Available                                                       2d18h
  62. 查看pvc
  63. [root@master sts]# kubectl get pvc
  64. NAME                STATUS   VOLUME   CAPACITY   ACCESS MODES   STORAGECLASS   AGE
  65. myappdata-myapp-0   Bound    pv003    5Gi        RWO                           38m
  66. myappdata-myapp-1   Bound    pv001    5Gi        RWO,RWX                       38m
  67. myappdata-myapp-2   Bound    pv002    5Gi        RWO,RWX                       38m
  68. 查看svc
  69. [root@master sts]# kubectl get svc
  70. NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
  71. kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP   56d
  72. myapp        ClusterIP   None         <none>        80/TCP    58s

扩展sts的pod

  1. [root@master sts]# kubectl scale sts myapp --replicas=5
  2. statefulset.apps/myapp scaled
  3. [root@master sts]# kubectl get pod
  4. NAME      READY   STATUS    RESTARTS   AGE
  5. myapp-0   1/1     Running   0          50m
  6. myapp-1   1/1     Running   0          50m
  7. myapp-2   1/1     Running   0          50m
  8. myapp-3   1/1     Running   0          11s
  9. myapp-4   0/1     Running   0          7s

缩容sts的pod

  1. [root@master sts]# kubectl patch sts myapp -p '{"spec":{"replicas":3}}'
  2. statefulset.apps/myapp patched
  3. You have new mail in /var/spool/mail/root
  4. [root@master sts]# kubectl get pod
  5. NAME      READY   STATUS        RESTARTS   AGE
  6. myapp-0   1/1     Running       0          4m12s
  7. myapp-1   1/1     Running       0          4m8s
  8. myapp-2   1/1     Running       0          4m4s
  9. myapp-3   1/1     Running       0          3m16s
  10. myapp-4   0/1     Terminating   0          3m12s

升级版本

  1. [root@master sts]# kubectl patch sts myapp -p '{"spec":{"updateStrategy":{"rollingUpdate":{"partition":4}}}}'
  2. statefulset.apps/myapp patched
  3. You have new mail in /var/spool/mail/root
  4. [root@master sts]# kubectl describe sts myapp
  5. Name:               myapp
  6. Namespace:          default
  7. CreationTimestamp:  Mon, 21 Jun 2021 12:34:07 +0800
  8. Selector:           app=myapp-pod
  9. Labels:             <none>
  10. Annotations:        <none>
  11. Replicas:           3 desired | 3 total
  12. Update Strategy:    RollingUpdate
  13.   Partition:        4                                                    //分区的方式进行升级，默认为0，就是审计所有，此处改为4，大于等于4的才会升级，其余的不会升级
  14. Pods Status:        3 Running / 0 Waiting / 0 Succeeded / 0 Failed
  15. Pod Template:
  16.   Labels:  app=myapp-pod
  17.   Containers:
  18.    myapp:
  19.     Image:        ikubernetes/myapp:v1
  20.     Port:         80/TCP
  21.     Host Port:    0/TCP
  22.     Environment:  <none>
  23.     Mounts:
  24.       /usr/share/nginx/html from myappdata (rw)
  25.   Volumes:  <none>
  26. Volume Claims:
  27.   Name:          myappdata
  28.   StorageClass:  
  29.   Labels:        <none>
  30.   Annotations:   <none>
  31.   Capacity:      5Gi
  32.   Access Modes:  [ReadWriteOnce]
  33. Events:
  34.   Type    Reason            Age    From                    Message
  35.   ----    ------            ----   ----                    -------
  36.   Normal  SuccessfulCreate  8m16s  statefulset-controller  create Claim myappdata-myapp-0 Pod myapp-0 in StatefulSet myapp success
  37.   Normal  SuccessfulCreate  8m16s  statefulset-controller  create Pod myapp-0 in StatefulSet myapp successful
  38.   Normal  SuccessfulCreate  8m12s  statefulset-controller  create Claim myappdata-myapp-1 Pod myapp-1 in StatefulSet myapp success
  39.   Normal  SuccessfulCreate  8m12s  statefulset-controller  create Pod myapp-1 in StatefulSet myapp successful
  40.   Normal  SuccessfulCreate  8m8s   statefulset-controller  create Claim myappdata-myapp-2 Pod myapp-2 in StatefulSet myapp success
  41.   Normal  SuccessfulCreate  8m8s   statefulset-controller  create Pod myapp-2 in StatefulSet myapp successful
  42.   Normal  SuccessfulCreate  7m20s  statefulset-controller  create Claim myappdata-myapp-3 Pod myapp-3 in StatefulSet myapp success
  43.   Normal  SuccessfulCreate  7m20s  statefulset-controller  create Pod myapp-3 in StatefulSet myapp successful
  44.   Normal  SuccessfulCreate  7m16s  statefulset-controller  create Claim myappdata-myapp-4 Pod myapp-4 in StatefulSet myapp success
  45.   Normal  SuccessfulCreate  7m16s  statefulset-controller  (combined from similar events): create Pod myapp-4 in StatefulSet myapp successful
  46.   Normal  SuccessfulDelete  4m15s  statefulset-controller  delete Pod myapp-4 in StatefulSet myapp successful
  47.   Normal  SuccessfulDelete  3m37s  statefulset-controller  delete Pod myapp-3 in StatefulSet myapp successful
  48. 升级镜像版本到v2
  49. [root@master sts]#  kubectl set image sts myapp myapp=ikubernetes/myapp:v2
  50. [root@master sts]# kubectl get pods
  51. NAME      READY   STATUS    RESTARTS   AGE
  52. myapp-0   1/1     Running   0          16m
  53. myapp-1   1/1     Running   0          16m
  54. myapp-2   1/1     Running   0          16m
  55. myapp-3   1/1     Running   0          79s
  56. myapp-4   1/1     Running   0          77s
  57. [root@master sts]# kubectl get pods myapp-4 -o wide
  58. NAME      READY   STATUS    RESTARTS   AGE   IP               NODE     NOMINATED NODE   READINESS GATES
  59. myapp-4   1/1     Running   0          91s   10.244.140.117   node02   <none>           <none>
  60. [root@master sts]# kubectl get pods myapp-4 -o yaml        #会发现只有myapp-4升级到了v2，其余的pod版本还是v1,想要升级其余pod，需要将partition的值改为0