config.system.indexBuilds:
	{
		_id : indexBuildUUID,
		collectionUUID : <UUID>,
		commitQuorum : <BSON>,
		indexes : [<index_name1>, <index_name2>, ….],
		prepareIndexBuilds : <bool>
		commitReadyMembers : [
			<hostAndPort1>,
			<hostAndPort2>,
			……
		]
	}