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IT Development

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This page documents how to configure or otherwise manage the WMUK servers.

Overview

The servers run:

• PHP 7.x
• MySQL
• Nginx (web server)

Paths

/etc/nginx

Nginx config path. Core vhosts are stored in /etc/nginx/sites-available. It is recommended not to touch these as they are in version control (SCM: config/nginx). Website vhosts can be configured with the tools detailed below.

/var/www

Root path for websites etc. Each virtual host will be given a sub-directory (with the name of the domain, see below).

Tools

Nginx/vhost management tools are stored on the SCM, using Mercurial, under config/Nginx-Config.

generate_vhost

Used to set up new virtual host domains based on skeleton files. See below.

nginx_ensite/nginx_dissite

Core tool for managing the master nginx configurations, should be rarely needed

htpasswd.py

Used to generate htpasswd files for HTTP basic auth (when the normal htpasswd tool is unavailable). Again, rarely needed.

Nginx

Very easy to configure using files, but an automated tool is also installed. Configuration guide for Nginx. If you change any Nginx configurations please commit them to the repository. In /etc/nginx, as root, run:

hg commit -m "<notes about what you have changed>"
hg push

Before you make changes, ensure that no existing updates are available (again run as root in /etc/nginx):

hg pull && hg update

Enable/Disable vhosts

Vhosts should be configured in /etc/nginx/sites-available, please name the file after the domain name (e.g. wikimedia.org.uk) for ease of reference. In general, all configurations for sub-domains should go into the top level domain vhost - but for more complex configurations it is often easier to split them up.

Always use nginx_ensite to then enable the domain (e.g. nginx_ensite <domain name>, then nginx reload) as this will check the config file syntax and correctly set up the symlink.

Using the generate_vhost tool

In a console run:

sudo generate_vhosts

It will ask you for the domain name you are hosting, and also to type in the public IP of the server (it will remind you). It will create a directory /var/www/<domain name> and copy a skeleton configuration into it. Then run:

sudo service nginx reload

This reloads the nginx config; if you see errors contact Tom.

Source code for the tool: Nginx-Config in the SCM

.htaccess??

.htaccess is a system of Apache web server most often used to do URL rewriting. Nginx does not support this method. If you have a .htaccess file then set up the vhost using the above tool then ping Tom who will convert the .htaccess to Nginx format.

Source Control

The Wikimedia UK source control server is located on Confidential at http://scm.wikimedia.org.uk. The management interface is Rhode Code. The server is capable of hosting repositories using either Git and Mercurial Distributed Version Control Software (DVCS).

SFTP access

Sometimes individuals may need access to the servers for updating files etc. No FTP server is installed, instead each individual should have a local user account placed in a chroot jail (to restrict their access) with SSH login disabled. The basics are; there is a user group called sftpusers which is configured in /etc/ssh/sshd_config to jail its users to /sftp/<username>. Add users to this group and and set their shell to /bin/login to enable SFTP only access.

useradd -g sftpusers -s /sbin/nologin <username>
mkdir /sftp/<username>

(the user will not have write permission to their jail root (/sftp/<username>) so you will have to create & chown their writable directories for them. e.g.

mkdir /sftp/<username>/<directory>
chown <username>:sftpusers /sftp/<username>/<directory>

Log in over SFTP to check access is jailed to the right directory.

Mediawiki

To simplify the maintenance work, all our Mediawiki instances are similar. The only differences are in the "LocalSettings.custom.php" (loaded from the default Mediawiki "LocalSettings.php") and in the "images" directory. Other files are exactly the same in all our Mediawiki instances.

Doing like that, we only need to maintain a Mediawiki instance, which plays the role of "master" instance. This "master" instance is located at "/var/www/devwiki" on the community server.

To create a new Mediawiki instance you need to:

1. create the new DNS entry
2. create the new Nginx vhost
3. create the repertory where to store Mediawiki code and data
4. copy the devwiki code into that directory
5. delete "LocalSettings.custom.php" and clean "images"
6. move "LocalSettings.php" to "LocalSettings.php.back"
7. launch the Web installation process
8. move "LocalSettings.php.back" to "LocalSettings.php"
9. create from scratch "LocalSettings.custom.php" based on the devwiki one

To update a Mediawiki instance you need:

• an up2date and well working devwiki instance
• the "updateMediawikiInstance.pl" script available in the /home/emmanuel/bin directory (comes from the Kiwix code repository http://code.kiwix.org/)
• to run it with the adequate options. The update process will erase the old MW instance with the new one (devwiki)

To custom a Mediawiki instance, you should not forget to:

• add any new extension to the devwiki extension directory (in addition to the wiki you want to customize)
• take care that any configuration must be put in "LocalSettings.custom.php" (otherwise this will be erased during the update process)