I've run into an issue specifying connection strings after our update from mongodb 2.6 to 3.0.

Previously, using the Ruby driver I could use the following call scheme to connect to a cluster with urls:

Mongo::Client.new(["one.com:10001", "two.com:20002"],

{..option...}

)

When connecting to the new 3.x instance, once I execute a query (or list databases, etc..) this causes a full timeout loop followed by an error: Mongo::Error::NoServerAvailable: No server is available matching preferences

With debug level logging on, I see lots of getaddrinfo errors while this is taking place: getaddrinfo: name or service not known

Given that urls seem to now require a mongodb:// prefix when connecting to a single db, I also tried

Mongo::Client.new(["mongodb://one.com:10001", "mongodb://two.com:20002"],

{..options...})

But that has the same result. The only way I could get it to work was with IPs, eg.

Mongo::Client.new(["192.168.0.1:10001", "192.168.0.2:20002"], {..options...}

)

In my mind, either this change was intended, and entering non-IPs should generate some sort of useful error about bad arguments rather than producing a timeout later, or this is a regression from previous behavior.