Wow. Just spent wayyyy to much time chasing down an issue getting a MongoDB Upstart daemon up and running using mongodb-stable on Ubuntu 10.4. The short answer is that the DB daemon was uncleanly shut down at some point, and a lock file was lingering. That lock file prevented MongoDB from starting. The solution to this is relatively simple. The database needs to have a repair run on it, which will remove the lock file.

To run the repair:

mongod --repair

You may have to sudo that, depending upon your particular setup. More info about repair can be found here: http://www.mongodb.org/display/DOCS/Durability+and+Repair

If you aren't able to repair because you need a config file specified as well, you're going to have to manually repair each DB on your box.

  1. Forcibly remove the lock on your database: sudo rm /var/lib/mongodb/mongodb.lock
  2. Open up the Mongo shell and run db.repairDatabase(); for each db.

The long issue: Why is it impossible for me to find any useful resources on Upstart, a component of the 10.4 LTS Ubuntu distro? I found absolutely nothing indicating where I could find Upstart logs, or something to help me narrow the search. Good grief.

 

Note: Thanks to Mike Dirolf for offering a safer solution than my first one. This post has been updated as a result of that.