Red Hat Enterprise Linux 9 Install

Installing LON-CAPA on a minimal Red Hat Enterprise Linux 9 System

This document guides you through the process of setting up a new LON-CAPA server or virtual machine running Red Hat Enterprise Linux 9 with a minimum of packages installed. The server or virtual machine will be configured solely as a LON-CAPA server and will be expected to have no other services running. Your server or virtual machine is expected to have a fast connection to the internet.

More information is available at http://install.lon-capa.org/.

Before you begin

Installing Linux is straightforward. 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.

Installation Overview

The installation process takes the following steps:

1. Obtain Red Hat Enterprise Linux 9 installation iso file or media
2. Determine Network Settings
3. Install Red Hat Enterprise Linux 9
4. Update your system
5. Install LON-CAPA
6. Create a Domain Coordinator
7. Start/Restart services
8. Log in to LON-CAPA

1. Obtain Red Hat Enterprise Linux 9

RHEL9 downloads are available from Red Hat: http://redhat.com/. Either download the Boot ISO or the RHEL 9 binary DVD ISO

2. Determine Network Settings

You will need to know the following network settings for your installation. Note:You must have a static IP address to use LON-CAPA. DHCP is not supported.

• ip address
• netmask
• hostname
• gateway
• domain name server(s)

3. Minimal Red Hat Enterprise Linux 9 Install

Installing Red Hat Enterprise Linux is straightforward. Documentation is available from https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/ Most of the installation screens are self explanatory. There are a few steps that require comment and are dealt with below.

Installation Language

Use English as your installation language.

Installation Destination

For a fresh install may want to use the automatic partitioning feature of the installer. If you want to customize partitioning check the "I will configure partitioning" radio button. 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 RHEL, /home should receive at least 10 to 12 GB. Since Mariadb uses the /var filesystem to store its databases you should have at least 4 GB of space available on /var. Be sure to include adequate swap space. A minimum is 512 MB, but you should typically have 1 or 2x as much swap space as you do physical RAM.

Network and Hostname

LON-CAPA will not 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 your network information. Enter your hostname

Software Selection

Check the "Minimal Install" radio button in the "Base Environment" panel, and check the "Standard" checkbox in the "Add-Ons for Selected Environment" panel.

Finish installing your server, reboot it, and log in as root.

Firewall Configuration

LON-CAPA can use Firewalld, available by default for RHEL 9. Enable access to standard web server ports (i.e., http and https):

systemctl enable firewalld
systemctl start firewalld
firewall-cmd --zone=public --permanent --add-service=http
firewall-cmd --zone=public --permanent --add-service=https
firewall-cmd --reload

4. Update your system

You will need a Red Hat subscription in order to have access to Red Hat updates. Your institution may have a Red Hat site license, and may maintain a Red Hat Satellite service which can be used to access updates. If not, you can obtain a free 30-day evaluation license from Red Hat. Once that has expired you will need to purchase a subscription. You can use the following comand to register your server/VM with the Red Hat account you created:

subscription-manager register

Once you have registered your server/VM you can than associate entitlements available from your subscription with your server/VM. The following command will show which repositories are enabled:

dnf repolist enabled

You will need the "rhel-9-for-x86_64-appstream-rpms" and "rhel-9-for-x86_64-baseos-rpms" repos enabled. If neither are enabled, enable them using:

subscription-manager repos --enable rhel-9-for-x86_64-appstream-rpms
subscription-manager repos --enable rhel-9-for-x86_64-baseos-rpms

Update your system to the latest versions of the system software using dnf.

dnf update

If the kernel was updated, reboot your system before continuing with the installation.

Set up access to package repositories

Enable access to the EPEL repository

dnf install https://dl.fedoraproject.org/pub/epel/epel-release-latest-9.noarch.rpm

Enable the "codeready-builder-for-rhel-9-x86_64-rpms" repository.

subscription-manager repos --enable codeready-builder-for-rhel-9-x86_64-rpms 

Install the loncapa.repo file from the LON-CAPA install site:

wget -O /etc/yum.repos.d/loncapa.repo http://install.loncapa.org/versions/redhat/9/loncapa.repo

Verify the required repositories are enabled

dnf repolist enabled

The list of enabled repos should be as follows:

Install and enable a Mail Transfer Agent (MTA), e.g., postfix

dnf install postfix
systemctl enable postfix
systemctl start postfix

Configure SELinux

The default RHEL9 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:

wget http://install.loncapa.org/versions/redhat/9/loncapa_selinux_config

Install the selinux config file

mv /etc/selinux/config /etc/selinux/config.backup
mv loncapa_selinux_config /etc/selinux/config
reboot

5. Installing LON-CAPA

Install prerequisites

Execute:

dnf install LONCAPA-prerequisites

This may take some minutes due to LON-CAPA's large number of dependencies.

Retrieve and execute LON-CAPA setup program

Retrieve the LON-CAPA setup with the following command:

wget http://install.loncapa.org/linux/install.tar

Extract the archive with the following command:

tar xf install.tar

This creates a directory named installation. Change to it and execute the setup script with the following commands:

cd installation
./install.pl

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.

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 ten possible actions, required changes will be made.

The possible actions are:

• Create the www user/group
• Install the package LON-CAPA uses to authenticate users.
• Set-up the MySQL (Mariadb) database
• Set-up MySQL (Mariadb) permissions
• Configure Apache web server
• Configure systemd security settings for Apache web server
• Configure start-up of services
• Check firewall settings
• Stop services not used by LON-CAPA, e.g., services for a print server: cups daemon
• Download LON-CAPA source code in readiness for installation

Determine LON-CAPA Settings

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.

Host Type (library or access)

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.

LON-CAPA domain

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. Restriction: One word, no hyphens, underscores, or special characters.
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.

LON-CAPA host id

Each LON-CAPA server requires a unique internal name. We use names such as "msul1" for the first library server. Restriction: One word, no hyphens, underscores, or special characters.

Domain's Primary Library Server ID

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.

Host administrator email

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 root@localhost.

Support email address

Enter an e-mail address here, so 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.

Configuring LON-CAPA

To configure and install LON-CAPA, execute the following commands:

cd /root/loncapa-X.Y.Z     (X.Y.Z should correspond to a version number like '2.11.5')
./UPDATE

You will need to enter the LON-CAPA configuration information you determined in the previous section.

6. Creating a Domain Coordinator

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. If installing a library server and an access server on separate machines or VMs you need only run make_domain_coordinator.pl on the library server.

cd /root/loncapa-X.Y.Z/loncom/build
perl make_domain_coordinator.pl USERNAME DOMAIN

7. Start/Restart Services

The LON-CAPA network services take a moment to start. Most misconfigurations will be apparent at this step.

/home/httpd/perl/loncontrol start
systemctl start httpd

If you receive warnings about missing perl modules, when starting the httpd service please make sure that the LONCAPA-prerequisites rpm is installed using this command:

rpm -q LONCAPA-prerequisites

If it is not installed, ensure that the required Linux repositories are enabled (see the "Set up access to package repositories" section above), then install it:

dnf install LONCAPA-prerequisites

If you still have errors, please contact the LON-CAPA Helpdesk: helpdesk at loncapa.org

Ensure that LON-CAPA network services and the httpd service are set to start on boot:

systemctl enable loncontrol
systemctl enable httpd

Point a web browser at your new machine and log in as the domain coordinator. Congratulations!

If things aren't working right

If you've followed the steps above and the server doesn't start or you think there's something wrong, please contact the LON-CAPA helpdesk. Installation/update support is available from: helpdesk at loncapa.org (replace " at " with @). 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.

Contact Us: lon-capa@lon-capa.org

Supported by the National Science Foundation under NSF-ITR 0085921, NSF-CCLI-ASA 0243126, and NSF-CCLI 0717790. Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. Initial funding for CAPA has been provided by the Alfred. P. Sloan Foundation and the Andrew W. Mellon Foundation.