In 3.0 the field box.info.cluster is renamed to box.info.replicaset. And there will be a new field box.info.cluster which will not have UUID and will have name field (for the whole cluster name, not for the single replicaset).

vshard.util should expose a function box_info_replicaset(info) which takes a box.info and returns replicaset. In < 3.0 it should return info.cluster. In >= 3.0 it should return info.replicaset. Usage example - uuid = util.box_info_replicaset(box.info).

I intentionally want to pass info as an argument. For cases when box.info is already done outside.

Also need to replace all the existing box.info.cluster usages with this new function.