This implements Bulk volume polling using ideas presented by
justin in https://github.com/kubernetes/kubernetes/pull/39564
But it changes the implementation to use an interface
and doesn't affect other implementations.
The input variable of function ConstructVolumeSpec is the volume spec
name instead of persistent disk ID. Previously the function directly
construct new volume spec by assigning volume spec name to persistent
disk ID, which will result in mismatching of mount path. The fix will
find the pdID according to mount path and construct volume spec with the
correct pdID.
This PR is to fix the issue in converting aws volume id from mount
paths. Currently there are three aws volume id formats supported. The
following lists example of those three formats and their corresponding
global mount paths:
1. aws:///vol-123456
(/var/lib/kubelet/plugins/kubernetes.io/aws-ebs/mounts/aws/vol-123456)
2. aws://us-east-1/vol-123456
(/var/lib/kubelet/plugins/kubernetes.io/mounts/aws/us-est-1/vol-123455)
3. vol-123456
(/var/lib/kubelet/plugins/kubernetes.io/mounts/aws/us-est-1/vol-123455)
For the first two cases, we need to check the mount path and convert
them back to the original format.
