+The number of Keepstore, shell and compute nodes listed above is a minimum. In a real production installation, you will likely run many more of each of those types of nodes. In such a scenario, you would probably also want to dedicate a node to the Workbench server and Crunch dispatcher, respectively. For performance reasons, you may want to run the database server on a separate node as well.
+
+h2(#repos). Arvados package repositories
+
+On any host where you install Arvados software, you'll need to set up an Arvados package repository. They're available for several popular distributions.
+
+h3. CentOS
+
+Packages are available for CentOS 6. First, register the Curoverse signing key in RPM's database:
+
+{% include 'install_redhat_key' %}
+
+Then save this configuration block in @/etc/yum.repos.d/arvados.repo@:
+
+<notextile>
+<pre><code>[arvados]
+name=Arvados
+baseurl=http://rpm.arvados.org/CentOS/$releasever/os/$basearch/
+</code></pre>
+</notextile>
+
+h3. Debian and Ubuntu
+
+Packages are available for Debian 7 ("wheezy"), Debian 8 ("jessie"), Ubuntu 12.04 ("precise"), and Ubuntu 14.04 ("trusty").
+
+First, register the Curoverse signing key in apt's database:
+
+{% include 'install_debian_key' %}
+
+Configure apt to retrieve packages from the Arvados package repository. This command depends on your OS vendor and version:
+
+table(table table-bordered table-condensed).
+|OS version|Command|
+|Debian 7 ("wheezy")|<notextile><code><span class="userinput">echo "deb http://apt.arvados.org/ wheezy main" | sudo tee /etc/apt/sources.list.d/arvados.list</span></code></notextile>|
+|Debian 8 ("jessie")|<notextile><code><span class="userinput">echo "deb http://apt.arvados.org/ jessie main" | sudo tee /etc/apt/sources.list.d/arvados.list</span></code></notextile>|
+|Ubuntu 12.04 ("precise")|<notextile><code><span class="userinput">echo "deb http://apt.arvados.org/ precise main" | sudo tee /etc/apt/sources.list.d/arvados.list</span></code></notextile>|
+|Ubuntu 14.04 ("trusty")|<notextile><code><span class="userinput">echo "deb http://apt.arvados.org/ trusty main" | sudo tee /etc/apt/sources.list.d/arvados.list</span></code></notextile>|
+
+{% include 'notebox_begin' %}
+
+Arvados packages for Ubuntu may depend on third-party packages in Ubuntu's "universe" repository. If you're installing on Ubuntu, make sure you have the universe sources uncommented in @/etc/apt/sources.list@.
+
+{% include 'notebox_end' %}
+
+Retrieve the package list:
+
+<notextile>
+<pre><code>~$ <span class="userinput">sudo apt-get update</span>
+</code></pre>
+</notextile>