[{"network_type":"ex","rack":[{"xxxx":{"asn":111111,"nodes":{"business":["sk550abcc1eb01.abc.com","sk550abcc1eb10.abc.com","sk550abcc1eb19.abc.com","sk550abcc1eb28.abc.com"]},"region":"ex-01","zone":"01a"}}]}]

db.collection.update({},{$rename:{"rack.xxxx":"details"}})