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Adds a database instance or replica set to a sharded cluster. The optimal configuration is to deploy shards across replica sets. This method must be run on a mongos instance.

The sh.addShard() method has the following parameter:

Parameter Type Description
host string The hostname of either a standalone database instance or of a replica set. Include the port number if the instance is running on a non-standard port. Include the replica set name if the instance is a replica set, as explained below.

The sh.addShard() method has the following prototype form:


The host parameter can be in any of the following forms:



Do not use localhost for the hostname unless your configuration server is also running on localhost.

The sh.addShard() method is a helper for the addShard command. The addShard command has additional options which are not available with this helper.


You cannot include a hidden member in the seed list provided to sh.addShard().


To add a shard on a replica set, specify the name of the replica set and the hostname of at least one member of the replica set, as a seed. If you specify additional hostnames, all must be members of the same replica set.

The following example adds a replica set named repl0 and specifies one member of the replica set: