I replaced the mongodb-10gen install with the Ubuntu package (mongodb-server, mongodb-client and dev).

apt-get install mongodb

Thereafter, I am now unable to connect to the REST interface, where it worked before.

Doing a wget to http://127.0.0.1:27018, I receive the following response:

Connecting to 127.0.0.1:27018... failed: Connection refused.

My previous /etc/mongodb.conf file had the following in:

#enable REST
rest = true

Adding it to the packaged conf file does not resolve the issue, not even after restarting.

I also tried changing the following with no effect:

# Disable the HTTP interface (Defaults to localhost:27018).
# nohttpinterface = true

to

# Disable the HTTP interface (Defaults to localhost:27018).
nohttpinterface = false

I have searched for days, and there doesn't seem to be anything on the Mongo site about a similar anomaly. If you have encountered a similar issue on Ubuntu Oneiric, please add your comments, even if you haven't found a solution to this issue.