The UNIX-based operating systems are extremely popular choices at the moment for hosting services, including web services, mail services, and, of course, database services. In this chapter, we’ll walk you through how to get MongoDB running on a popular Linux distribution: Ubuntu. To make things simple (or perhaps more complicated, depending on your point of view), you have two ways of installing MongoDB under Ubuntu: you can install the packages automatically through socalled repositories, or you can install it manually. The next couple sections will walk you through both options.

Installing MongoDB Through the Repositories

Repositories are basically online directories filled with software. Every package contains information about the version number, prerequisites, and possible incompatibilities. This information is useful when you need to install a software package that requires another piece of software to be installed first because the prerequisites can be installed at the same time. The default repositories available in Ubuntu (and other Debian-based distributions) contain MongoDB, but they may be out-of-date versions of the software. Therefore, let’s tell aptitude (the software you use to install software from repositories) to look at a custom repository. To do this, you need to add the following line to your repository-list (/etc/apt/sources.list): deb http://downloads.mongodb.org/distros/ubuntu (version.number) 10gen In the preceding line, version.number represents the distribution version. Let’s say your Ubuntu is version 10.4 (also called Ubuntu Lucid); in that case, the full line would look like this: deb http://downloads.mongodb.org/distros/ubuntu 10.4 10gen Next, you need to tell aptitude that it contains new repositories; you can do so using aptitude’s update command: $ sudo aptitude update The preceding line made aptitude aware of your manually added repository. This means you can now tell aptitude to install the software itself. You do this by typing the following command in the shell: $sudo aptitude install mongodb-stable As you may have guessed, the preceding line installs the current stable (production) version from MongoDB. If you wish to install the unstable (development) version from MongoDB, type in the following command instead: $ sudo aptitude install mongodb-unstable And this command installs the nightly build: $ sudo aptitude install mongodb-snapshot That’s all there is to it. At this point, MongoDB has been installed and is (almost) ready to use!

Installing MongoDB Manually

Next, we’ll cover how to install MongoDB manually. Given how easy it is to install MongoDB with aptitude automatically, you might wonder why you would want to install the software manually. For starters, not all Linux distributions use aptitude. Sure, a bunch of them do (including primarily the ones that are based on Debian Linux), but some don’t. Also, the packaging remains a work in progress, so it might be the case that there are versions not yet available through the repositories. It’s also possible that the version of MongoDB you want to use isn’t included in the repository (you might want to install an older version automatically). Installing the software manually also gives you the ability to run multiple versions of MongoDB at the same time. You’ve decided which version of MongoDB you would like to use, and you’ve downloaded it to your Home directory. Next, you need to extract the package with the following command: $ tar xzf mongodb-linux-x86_64-latest.tgz The preceding command extracts the entire contents of the package to a new directory called mongodb-linux-x86_64-xxxx-yy-zz; this directory is located under your current directory. This directory will contain a number of subdirectories and files. The directory that contains the executable files is called the bin directory. We will cover which applications perform which tasks shortly. However, you don’t need to do anything further to install the application. Indeed, it doesn’t take much more time to install MongoDB manually—depending on what else you need to install, it might even be faster. Manually installing MongoDB does have some downsides, however. For example, the executables that you just extracted and found in the bin directory can’t be executed from anywhere except the bin directory by default. Thus, if you want to run the mongod service, you will need to do so directly from the aforementioned bin directory. This downside highlights one of the benefits of installing MongoDB through repositories.