kubernetes: PVCs do not get assigned to correct AZ as where the pod needs to be scheduled

/kind bug

What happened: I am trying to deploy a stateful set with PVCs to a set of 5 instances spread across 2 AZs. The stateful set has 5 pods, and I have set anti affinity so that there will be 1 pod per instance. The instances came up in AZs a-b-a-b-a. When I deploy the stateful set, their PVCs come up in AZs b-a-b-a-b. Thus the last pod in the set cannot be scheduled due to NoVolumeZoneConflict.

What you expected to happen: The PVCs should be assigned to the same AZ as the instance where the pod that requires it gets scheduled. Is there any way for me to make this happen?

How to reproduce it (as minimally and precisely as possible): Deploy a stateful set of 5 replicas with PVCs and anti pod affinity to a cluster with 5 nodes on 2 AZs:

spec:
  replicas: 5
  template:
    spec:
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
          - labelSelector:
              matchExpressions:
              - key: app
                operator: In
                values:
                - foo
            topologyKey: kubernetes.io/hostname
  volumeClaimTemplates:
  - metadata:
      name: datadir
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 20Gi

Anything else we need to know?:

Environment:

• Kubernetes version (use kubectl version):

Client Version: version.Info{Major:"1", Minor:"7", GitVersion:"v1.7.1", GitCommit:"1dc5c66f5dd61da08412a74221ecc79208c2165b", GitTreeState:"clean", BuildDate:"2017-07-14T02:00:46Z", GoVersion:"go1.8.3", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"7", GitVersion:"v1.7.0", GitCommit:"d3ada0119e776222f11ec7945e6d860061339aad", GitTreeState:"clean", BuildDate:"2017-06-29T22:55:19Z", GoVersion:"go1.8.3", Compiler:"gc", Platform:"linux/amd64"}

• Cloud provider or hardware configuration**: AWS
• OS (e.g. from /etc/os-release):

PRETTY_NAME="Debian GNU/Linux 8 (jessie)"
NAME="Debian GNU/Linux"
VERSION_ID="8"
VERSION="8 (jessie)"
ID=debian
HOME_URL="http://www.debian.org/"
SUPPORT_URL="http://www.debian.org/support"
BUG_REPORT_URL="https://bugs.debian.org/"

• Kernel (e.g. uname -a):

Linux 4.4.65-k8s x86_64 GNU/Linux

• Install tools: custom
• Others: