Public command format:

{
  updateZoneKeyRange: <string namespace>,
  min: <BSONObj min>,
  max: <BSONObj max>,
  zone: <string zone|null>
}

Internal command format:

{
  _configsvrUpdateZoneKeyRange: <string namespace>,
  min: <BSONObj min>,
  max: <BSONObj max>,
  zone: <string zone|null>,
  writeConcern: <BSONObj>
}

Requirements:
1. min < max.
2. zone should be an existing shard zone.
3. [min, max) should not overlap with existing zoned range.

Note:

• passing a null zone is for removing an existing zoned range [min, max) from it's existing zone. The [min, max) should exactly match a real zoned range, otherwise, it will be a no-op.