kubernetes - 在部署更新时重新附加卷声明

Question

我正在使用持久卷声明将数据存储在容器中:

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: test-pvc
  labels:
    type: amazonEBS
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 5Gi

规范中的声明:

spec:
  volumes:
  - name: test-data-vol
    persistentVolumeClaim:
      claimName: test-pvc
  containers:
  - name: test
    image: my.docker.registry/test:1.0
    volumeMounts:
    - mountPath: /var/data
      name: test-data-vol

当我第一次启动它时，这个卷安装正确。但是当我尝试更新容器镜像时:

-    image: my.docker.registry/test:1.0
+    image: my.docker.registry/test:1.1

此卷无法挂载到新 pod:

# kubectl get pods
test-7655b79cb6-cgn5r       0/1     ContainerCreating   0          3m
test-bf6498559-42vvb        1/1     Running             0          11m

# kubectl describe test-7655b79cb6-cgn5r
Events:
  Type     Reason                 Age   From                                                  Message
  ----     ------                 ----  ----                                                  -------
  Normal   Scheduled              3m5s  default-scheduler                                     Successfully assigned test-7655b79cb6-cgn5r to ip-*-*-*-*.us-west-2.compute.internal
  Warning  FailedAttachVolume     3m5s  attachdetach-controller                               Multi-Attach error for volume "pvc-2312eb4c-c270-11e8-8d4e-065333a7774e" Volume is already exclusively attached to one node and can't be attached to another
  Normal   SuccessfulMountVolume  3m4s  kubelet, ip-*-*-*-*.us-west-2.compute.internal  MountVolume.SetUp succeeded for volume "default-token-x82km"
  Warning  FailedMount            62s   kubelet, ip-*-*-*-*.us-west-2.compute.internal  Unable to mount volumes for pod "test-7655b79cb6-cgn5r(fab0862c-d1cf-11e8-8d4e-065333a7774e)": timeout expired waiting for volumes to attach/mount for pod "test-7655b79cb6-cgn5r". list of unattached/unmounted volumes=[test-data-vol]

Kubernetes 似乎无法将此卷从一个容器重新附加到另一个容器。如何正确处理？当旧版本停止时，我需要新版本的部署使用此卷数据。

Answer 1

这里的问题是 EBS 卷是 ReadWriteOnce并且只能挂载到单个 Pod，因此当您进行滚动更新时，旧 Pod 会保存该卷。为此，您必须使用 StatefulSet 或者您可以使用任何 ReadWriteMany 光伏类型。

Kubernetes Deployment有时更好地用于无状态 pod。

您始终可以使用蛮力方法，强制删除持有该卷的 pod。确保 Reclaim Policy 设置为 Retain .