[{"_id":1,"env":"pilot","service_name":"test1","instances":[{"location":"server1","type":"passive",},{"worker_location":"server2","type":"active"}]},{"_id":2,"env":"pilot","service_name":"test2","instances":[{"worker_location":"server1","type":"active",},{"worker_location":"server2","type":"passive"}]}]

db.collection.aggregate([{$unwind:"$instances"},{$match:{$and:[{env:"pilot"},{"instances.type":"active"},{"instances.worker_location":"server2"}]}},{$project:{_id:1,service_name:1}}])