warning: could not initialize balancer, please check that all shards and config servers are up: socket exception

[VJ]

Hello.  I have a 3-node shard cluster running in our hosted data center.  A mongod and a configsvr are running on each of the 3 servers.  I can connect to this cluster from inside the data center environment with a mongos.  Using the same mongos configuration, I cannot connect to this cluster from a mongos running on an EC2 server.  I get the following error in the log:

   warning: could not initialize balancer, please check that all shards and config servers are up: socket exception

I don't think this is a firewall issue??  From the same EC2 server, I can connect to each of the mongod and configsvr thru the mongo shell.  I've also restarted all the mongod and configsvr processes.

Thanks for your help.

[VJ]

Issue resolved -- user error!  I was using the internal IPs for our data center servers in the /etc/mongos.conf and in the addShard commands.  When I switched to the external IPs, the mongos started, and I was able to configure the environment.