In OM HA, currently, when initiate multipart upload is called, in applyTransaction() on all OM nodes, it generates a multipartUploadID. So, each OM generates a new multipartUploadID. But the response we give to the client is multipartUploadID generated from OM leader node.
Because this is the same multipartUploadID used during openKey and commitKey. (This will be sent from client who is creating this multipart upload for a key).
To solve this issue, we take similar approach of openKey, where multipartUploadID will be generated in startTransaction and the same should be sent to all OM's. So that during applyTransaction all OM's will have the same multipartUploadID.