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- Update CentOS 6 instructions to include enabling EPEL repo.

<h1>Installing LON-CAPA on a minimal CentOS Linux 6 System</h1>
<p>
This document guides you through the process of setting up a new LON-CAPA
server running CentOS Linux 6 with a minimum of packages installed.  
The computer will be configured solely as a LON-CAPA server and will be 
expected to have no other services running.  Your server is expected to have
a reasonably fast connection to the internet.
</p><p>
More information is available at 
<a href="http://install.lon-capa.org/">http://install.lon-capa.org/</a>.
</p>

<h2>Before you begin</h2>
<p>
Installing Linux is getting easier and easier.
You will be required to log in to the machine and execute
some routine Unix commands.  Familiarity with the Apache web server, mod_perl, 
perl, and MySQL are not required to install and run LON-CAPA.
</p>

<h2>Installation Overview</h2>
<p>
The installation process takes the following steps:
</p>
<ol>
  <li><a href="#obt">Obtain CentOS Linux 6 installation CDs</a></li>
  <li><a href="#net">Determine Network Settings</a></li>
  <li><a href="#lin">Install CentOS Linux 6</a></li>
  <li><a href="#upd">Update your system</a></li>
  <li><a href="#ilc">Install LON-CAPA</a></li>
  <li><a href="#cdc">Create a Domain Coordinator</a></li>
  <li><a href="#sts">Start/Restart services</a></li>
  <li><a href="#log">Log in to LON-CAPA</a></li>
</ol>

<hr>
<h2>1. <a name="obt">Obtain CentOS Linux 6 DVD or CD for net install</a></h2>
<p>
CentOS isos can be obtained from links included on the <a href="http://mirror.centos.org/centos/6/isos/">CentOS download page</a>
</p>

<h2>2. <a name="net">Determine Network Settings</a></h2>
<p>
You will need to know the following network settings for your installation.
<b>Note:</b>You must have a static IP address to use LON-CAPA.
DHCP is <em>not</em> supported.

<ul>
  <li>ip address </li>
  <li>netmask </li>
  <li>hostname </li>
  <li>gateway </li>
  <li>domain name server(s) </li>
</ul>

<h2>3. <a name="lin">Minimal CentOS Linux 6 Install</a></h2>
<p>
Installing CentOS Linux is straightforward. 
Documentation is available from 
<a href="http://wiki.centos.org/">http://wiki.centos.org/</a>
Most of the installation screens are self explanatory.
There are a few steps that require comment and are dealt with below.
</p>
<dl style="list-style:square outside none">
   <dt>Installation Language</dt>
   <dd>Use English as your installation language.</dd>
   <dt>Installation Type</dt>
   <dd>If this is a fresh install choose "Install CentOS Linux Server". If updating from a previous LON-CAPA installation on an earlier Redhat or Fedora version you may prefer to choose the upgrade option, although if you established a separate partition for /home it will be faster to perform an install instead of an upgrade, and use "Create Custom Layout" to set up partitions - making sure to select the "unchanged data" option for the /home partition, in order to preserve your existing LON-CAPA data. A full back-up to tape or some external system is also strongly advised when updating the operating system in use on an existing LON-CAPA server.</dd>

   <dt>Partitioning your Drive</dt>
   <dd>For a fresh install may want to use the automatic partitioning feature of the installer,
       however you should review the results and be prepared to modify them.  If you want to customize partitioning use "Create Custom Layout".
       LON-CAPA resource files are stored in the /home directory, so the
       majority of the disk space should be allocated here.  If you have 20 GB 
       of space for CentOS, /home should receive at least 10 to 12 gigs.  
       Since MySQL uses the /var filesystem to store its databases you should
       have at least 4 gigs of space available on /var.  Be sure to 
       include adequate swap space.  A minimum is 512 Megs, but you should
       typically have 1 or 2x as much swap space as you do physical RAM.</dd>

   <dt>Network Configuration</dt>
   <dd>LON-CAPA will <b>not</b> work with a machine set up to use a dynamic 
       IP address.  When configuring your network card, be sure to unselect
       the DHCP option and enter in your network information.</dd>
   <dt>Software</dt>
   <dd>If given an option to choose which package to install, select a minimal install and then uncheck all packages except "Base" in the Base System category.</dd>
</dl>

<p>
Finish installing your server, reboot it, and log in as root.
</p>

<h2>3. <a name="upd">Update your system</a></h2>
<p>
Enable access to the EPEL repository
</p>
<pre>
yum install epel-release
</pre>
<p>
Update your system to the latest versions of the system software using yum.
</p>
<pre>
rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
yum update
</pre>
<p>
Reboot your system before continuing with the installation.
</p>
<p>
Retrieve the centos6_loncapa_yum file from the LON-CAPA install site:
</p>
<pre>
yum install wget
wget http://install.loncapa.org/versions/centos/6/centos6_loncapa_yum.conf
</pre>
<p>
Install the centos6_loncapa_yum.conf
</p>
<pre>
mv /etc/yum.conf /etc/yum.conf.backup
cp centos6_loncapa_yum.conf /etc/yum.conf
yum update
</pre>
<p>
Verify the required repositories are enabled:
</p>
<pre>
yum repolist enabled
</pre>
<p>
The list of enabled repos should be as follows (where $basearch = x86_64 or i386):
</p>
<table style="border: 0px; border-collapse: collapse;">
<tr><th>repo id</th><th>repo name</th></tr>
<tr><td>base</td><td>CentOS-6 - Base<td></tr>
<tr><td>epel</td><td>Extra Packages for Enterprise Linux 6 - $basearch</td></tr>
<tr><td>extras</td><td>CentOS-6 - Extras</td></tr>
<tr><td>loncapa-updates-basearch</td><td>CentOS 6 LON-CAPA $basearch Updates</td></tr>
<tr><td>loncapa-updates-noarch</td><td>CentOS 6 LON-CAPA noarch Updates</td></tr>
<tr><td>updates</td><td>CentOS-6 - Updates<td></tr>
</table>

<h3>Configure SELinux</h3>
<p>
The default CentOS 6 installation includes SELinux enabled. Until such time as an SELinux security policy has been created for LON-CAPA, SELinux should be disabled.
Retrieve the loncapa_selinux_config file from the LON-CAPA install site:
</p>
<pre>
wget http://install.loncapa.org/versions/centos/6/loncapa_selinux_config
</pre>
<p>
Install the selinux config file
</p>
<pre>
mv /etc/selinux/config /etc/selinux/config.backup
mv loncapa_selinux_config /etc/selinux/config
reboot
</pre>

<h2>4. <a name="ilc">Installing LON-CAPA</a></h2>
<h3>Import the LON-CAPA encryption key</h3>
<pre>rpm --import http://install.loncapa.org/versions/centos/RPM-GPG-KEY-loncapa</pre>
<h3>Install prerequisites</h3>
<p> Execute: </p>
<pre>
yum install LONCAPA-prerequisites
</pre><p>
This may take some minutes due to LON-CAPA's large number of dependencies.
</p>
<h3>Configure firewall and network</h3>
<p> Execute: </p>
<pre>
system-config-firewall-tui
</pre>
<ol>
   <li>Select Firewall: Enabled, and Customize, to allow
       incoming: SSH (remote login), WWW (HTTP) and secure WWW
       (HTTPS).
   </li>
   <li> Select OK, and then Yes to save</li>
</ol>

<h3>Retrieve and execute LON-CAPA setup program</h3>
<p>
Retrieve the LON-CAPA setup with the following command:
</p>
<pre>
wget http://install.loncapa.org/linux/install.tar
</pre>
<p>
Extract the archive with the following command:
</p>
<pre>
tar xf install.tar
</pre>
<p>
This creates a directory named <tt>installation</tt>.  Change to it and
execute the setup script with the following commands:
</p>
<pre>
cd installation
./install.pl
</pre>
<p>
The script is used to prepare a Linux system to run LON-CAPA, and can also be
used to check the configuration of a system on which LON-CAPA has already been installed.  Typically, though, you will run this script only once, when you first install LON-CAPA.
</p>
<p>
The script will analyze your system to determine which actions are recommended.  The script will then prompt you to choose the actions you would like taken.
Once a choice has been entered for all nine possible actions, required changes will be made.
</p>
<p>The possible actions are:</p>
<ul>
<li>Create the www user/group</li>
<li>Install the package LON-CAPA uses to authenticate users.</li>
<li>Set-up the MySQL database</li>
<li>Set-up MySQL permissions</li>
<li>Configure Apache web server</li>
<li>Configure start-up of services</li>
<li>Check firewall settings</li>
<li>Stop services not used by LON-CAPA,<br>
    e.g., services for a print server: cups daemon</li>
<li>Download LON-CAPA source code in readiness for installation</li>
</ul>

<h3>Determine LON-CAPA Settings</h3>
<p>
LON-CAPA requires a number of identifying parameters to be set in order
for it to function at all.  Below is a list with descriptions.
</p>
<dl>
  <dt>Host Type (library or access)</dt>
  <dd>The server must be designated a 'library' or an 'access' server.  In
      general you should have a library server for your instructors to create
      their course content on and run their courses.  Students should connect
      to access servers.  If you are doing the first install of LON-CAPA at 
      your site, or if you are playing with it for your own edification you
      should make your machine a 'library' server.</dd>
  <dt>LON-CAPA domain</dt>
  <dd>Each site or school which installs LON-CAPA needs its own domain.
      Here at MSU we use 'msu'.  You should choose something short but
      meaningful.  <i>Restriction: One word, no hyphens, underscores, or 
      special characters.</i><br>Domain names which include a departmental 
      abbreviation are not recommended as although LON-CAPA may start in
      a single department, other departments frequently join subsequently.
      For a domain name: 'msu' is a superior choice to 'msuphys' for example.
  </dd>
  <dt>LON-CAPA host id</dt>
  <dd>Each LON-CAPA server requires a unique internal name.  We use names
      such as "msul1" for the first library server. <i>Restriction: One word, 
      no hyphens, underscores, or special characters.</i>
  </dd>
  <dt>Domain's Primary Library Server ID</dt>
   <dd>If you are setting up a domain with a single library server, then the domain's primary library server ID will be the LON-CAPA host id of that server (e.g., msul1). Once your domain grows and you need to add more servers, one of the library servers in the domain should be assigned as the domain's primary library server.  This will be where domain-wide settings will be stored.<dd>
  <dt>Host administrator email</dt>
  <dd>The amount of email sent to this address is relatively minimal.  Messages
      are sent every time the system starts up, or if the system is in 
      serious trouble. On a laptop, make this <tt>root@localhost</tt>.
  </dd>
  <dt>Support email address</dt>
  <dd>If you enter an e-mail address here, then users of the system  
      will be able to click an "Ask Helpdesk" link in the system to 
      display a web form which they will complete to request support from
      your institution's helpdesk. On form submission the contents 
      will be sent to the e-mail address you specify. 
  </dd>
</dl>

<h3>Configuring LON-CAPA</h3>
<p>
To configure and install LON-CAPA, execute the following commands:
</p>
<pre>
cd /root/loncapa-X.Y.Z     (X.Y.Z should correspond to a version number like '2.10.0')
./UPDATE
</pre>
<p>
You will need to enter the LON-CAPA configuration information you determined 
in the previous section.
</p>

<h2>6. <a name="cdc">Creating a Domain Coordinator</a></h2>
<p>
You will need at least one user at your site who has the role of
'domain coordinator'.  This user creates accounts for other users and
grants them additional privileges.  The make_domain_coordinator.pl script
invoked below requires that you enter the user's password.
Feel free to use the "passwd username" command to change it later.
Replace USERNAME and DOMAIN with an appropriate user name and your domain.
</p>
<pre>
cd /root/loncapa-X.Y.Z/loncom/build
perl make_domain_coordinator.pl USERNAME DOMAIN
</pre>

<h2>7. <a name="sts">Start/Restart Services</a></h2>
<p>
The LON-CAPA network services take a moment to start.  Most misconfigurations
will be apparent at this step.
</p>
<pre>
/etc/init.d/loncontrol start
/etc/init.d/httpd start
</pre>
<p>
If you receive warnings when starting the httpd about missing perl modules,
please make sure you followed the instructions in 
<b>Installing LON-CAPA Dependencies</b>.  If you still have errors, please
contact the MSU LON-CAPA group.
</p>

<h2>8. <a name="log">Log in to your LON-CAPA Machine</a></h2>
<p>
Point a web browser at your new machine and log in as the domain
coordinator.  Congratulations!
</p>

<hr>
<h2>If things aren't working right</h2>
<p>
If you've followed the steps above and the server doesn't start or you think 
there's something wrong, please send a <a href="http://help.loncapa.org/help">help request</a> to the MSU LON-CAPA group.  If there were errors in installation of the dependency RPMs or errors during the
automatic setup, please send us as much information as possible.
If some part of this document is unclear please let us know.
</p>