Question

Has anyone been able to connect to a MongoDB replica set using rmongodb? No matter how I configure mongo.create I get an authentication error, even though the same host/username/password work fine when connecting via the mongo shell.

My code does the equivalent of:

> mongo.create(c("rs-1.mysite.com:12345","rs-2.mysite.com:12345"), "rsName", "user", "password", "my_db")
Unable to connect to replset
Authentication failed.

Update:

Looking at the logs of all the nodes in the replica set, I do not see any attempt to authenticate when I run the code above. Therefore, this may be a rmongodb bug.

Answer 1

As Sim has noted, rmongodb 1.0.3 does not resolve hostnames.

It is, however, possible to connect to replica sets from rmongodb with with a few caveats:

• you must include all hostnames (if the primary isn’t found in the seed host list, rmongodb will fail to connect)
• hostnames must be provided as IPs
• if using an admin user, you must first auth to the admin database (this, at least, is expected behaviour but worth noting)
• I could only get the connection to work by not providing a replSet name

So my working connect string looks like:

mongo.create(c("192.168.1.123:27017","192.168.1.124:27018","192.168.1.125:27017"),"","user","password", "thedb")

NB: I only tested this with MongoDB 2.2.0.