Deploying shard replica sets

Now, we'll repeat a very similar process for each member of the sharded cluster. In our illustration, we'll initiate three single-node replica sets, each representing a shard. The mongod.conf file for each shard is similar to the following:

systemLog:
   destination: file
   path: "/var/log/mongodb/mongodb.log"
   logAppend: true
storage:
   dbPath: "/data/db"
   journal:
      enabled: true
net:
   bindIp: 0.0.0.0
   port: 27018
replication:
   replSetName: repl_shard_1
sharding:
    clusterRole: shardsvr

To initialize the shard replica set, as described in the previous sub-section, we open a mongo shell to each of the member servers in turn. It's important to add the --port 27018 option when opening the shell. We can then initialize the replica set using the following shell commands:

doc = {
    _id : "repl_shard_1",
    members: [
        { _id: 1, host: "shard1.biglittle.local:27018" }
    ]
}
rs.initiate(doc);

The resulting...