Installing MongoDB 1.8.1, in my case as a developer database, is easy. This blog post just itemises all the steps so that you can pretty much blindly follow along. I’ll probably use these steps myself as I seem to be doing this regurlarly

Download the 64bit Linux binaries from here and unzip the contents to /usr/local.

cd /tmp
wget http://fastdl.mongodb.org/linux/mongodb-linux-x86_64-1.8.1.tgz
sudo tar -zxf /tmp/mongodb-linux-x86_64-1.8.1.tgz -C /usr/local

Setup some symbolic links.

sudo ln -s /usr/local/mongodb-linux-x86_64-1.8.1 /usr/local/mongodb
sudo ln -s /usr/local/mongodb/bin/bsondump /usr/local/bin/bsondump
sudo ln -s /usr/local/mongodb/bin/mongo /usr/local/bin/mongo
sudo ln -s /usr/local/mongodb/bin/mongod /usr/local/bin/mongod
sudo ln -s /usr/local/mongodb/bin/mongodump /usr/local/bin/mongodump
sudo ln -s /usr/local/mongodb/bin/mongoexport /usr/local/bin/mongoexport
sudo ln -s /usr/local/mongodb/bin/mongofiles /usr/local/bin/mongofiles
sudo ln -s /usr/local/mongodb/bin/mongoimport /usr/local/bin/mongoimport
sudo ln -s /usr/local/mongodb/bin/mongorestore /usr/local/bin/mongorestore
sudo ln -s /usr/local/mongodb/bin/mongos /usr/local/bin/mongos
sudo ln -s /usr/local/mongodb/bin/mongosniff /usr/local/bin/mongosniff
sudo ln -s /usr/local/mongodb/bin/mongostat /usr/local/bin/mongostat

The first “ln -s” above sets up a handy symbolic link between the versioned mongodb folder and its unversioned counterpart. When 10Gen release updates, say version 1.8.2, all you need to do is download, unzip, and link the ’1.8.2 mongodb folder’ to the unversioned folder and ‘hey presto’ everything should just work.

To get an init script working cleanly with this setup, download mine from my Github ‘dotfiles’ repo. Please note – my init script enables journaling and the REST interface (on line 51).

wget https://github.com/ijonas/dotfiles/raw/master/etc/init.d/mongod
sudo mv mongod /etc/init.d/mongod
sudo chmod +x /etc/init.d/mongod

You’ll need to add a mongodb user and prep some folders

sudo useradd mongodb
sudo mkdir -p /var/lib/mongodb
sudo mkdir -p /var/log/mongodb
sudo chown mongodb.mongodb /var/lib/mongodb
sudo chown mongodb.mongodb /var/log/mongodb

Also, you need to activate your MongoDB service’s init script by adding it to your system’s run-level configuration. That way the service will startup during the boot sequence and stop nicely during the OS’ shutdown procedure.

sudo update-rc.d mongod defaults

Lastly to launch MongoDB

/etc/init.d/mongod start

Good luck!

UPDATE: Since April 6 Ubuntu now has prefabbed packages containing MongoDB 1.8.1, maintained by 10Gen. See the instruction below.