Cookbook

All the things you might need to do as an organizer or a root are documented here.

Install a package for the contestants

The recommended way to add a package for the contestants is to add it in the list of packages, so that it will be also installed in future editions. Simply edit ansible/roles/rfs_packages/tasks/main.yml and add the wanted packages where appropriate, then redeploy:

ansible-playbook playbook-rfs-container.yml

However, sometimes you might not want to add a package in a permanent fashion, and just want to install something in a quick and dirty way on all the RFS exports. In that case, use an Ansible ad-hoc command like this:

ansible rfs_container -m shell -a "pacman -S mypackage"

Switching in and out of contest mode

Contest mode is the set of switches to block internet access to the users and give them access to the contest ressources.

Switching to contest mode is completely automated in Ansible. Initially, the inventory should contain this default configuration, which disables contest mode:

contest_enabled: false
contest_started: false

Switching to contest mode can be done in two steps:

1. Edit your inventory and enable these two values:

   contest_enabled: true
   contest_started: true
   

2. Run the following ansible command:

   ansible-playbook playbook-all-sadm.yml --tags contest_mode
   

Once the contest is over, you will want to go back to a configuration where everyone can access the internet, but you do not want to remove the game packages, because you will need them to run tournament matches. You can go to a configuration that is out of contest mode, but where the contest resources are no longer considered “secret” and are installed on the machines:

1. Change your inventory values to this:

   contest_enabled: false
   contest_started: true
   

2. Run the ansible command again:

   ansible-playbook playbook-all-sadm.yml --tags contest_mode
   

Customize the wallpaper

To customize the desktop wallpaper, edit your inventory to add a custom wallpaper URL like this:

wallpaper_override_url: "https://prologin.org/static/archives/2009/finale/xdm/prologin2k9_1280x1024.jpg"

Then, run the following command:

ansible-playbook playbook-rfs-container.yml --tags wallpaper

This will install the new wallpaper at /opt/prologin/wallpaper.png.

The following DE are setup to use this file:

• i3

• awesome

• Plasma (aka. KDE)

• XFCE

Gnome-shell is still to be done.

Customize the lightdm theme

TODO

Sending announcements

To send pop-up announcements on all the user’s machines, use an Ansible ad-hoc command like this:

ansible user -m shell -a "/usr/bin/xrun /usr/bin/zenity --info --text='Allez manger !' --icon-name face-cool"

xrun is a binary we install on all the user machines that knows how to find the currently running X server and sets all the required environment variables to run a GUI program on the remote machine.

User related operations

Most of the operations are made very simple with the use of udb. If you are an organizer, you can access udb in read only mode. If you are a root, you obviously have write access too.

udb displays the information (including passwords) of every contestant to organizers. Organizers can’t see the information of other organizers or roots.

All services should be using udb for authentication. Synchronization might take up to 5 minutes (usually only one minute) if anything is changed.

Giving back his password to a contestant

First of all, make sure to ask the contestant for his badge, which he should always have on him. Use the name from the badge to look up the user in the udb. The password should be visible there.

Adding an organizer

Root only. Go to udb and add a user with type orga.

Machine registration

mdb contains the information of all machines on the contest LANs. If a machine is not in mdb, it is considered an alien and won’t be able to access the network.

All of these operations are root only. Organizers can’t access the mdb administration interface.

Adding a user machine to the network

In the mdb configuration, authorize self registration by adding a VolatileSetting allow_self_registration to true. Netboot the user machine - it should ask for registration details. After the details have been entered, the machine should reboot to the user environment. Disable allow_self_registration when you’re done.

Adding a machine we don’t manage to the user network

Some organizers may want to use their laptop. Ask them for their MAC address and the hostname they want. Finally, insert a mdb machine record with machine type orga using the IP address you manually allocated (if you set the last allocation to 100, you should assign the IP .100). Wait a minute for the DHCP configuration to be synced, and connect the laptop to the network.

Network FS related operations

Two kind of network file systems are used during the finals, the first one is the Root File System: RFS, the second is the Home File System: HFS. The current setup is that a server is both a RFS and a HFS node.

The RFS is a read-only NFS mounted as a rootnfs in Linux. It is replicated over multiple servers to ensure minimum latency over the network.

The HFS is a read-write, exclusive, user-specific export of their home. In other words, each user has it’s own personal space that can only be mounted once at a time. The HFS exports are sharded over multiple servers.

Resetting the hfs

If you need to delete every /home created by the hfs, simply delete all nbd files in /export/hfs/ on all HFS servers and delete entries in the user_location table of the hfs’ database:

# For each hfs instance
rm /export/hfs/*.nbd

echo 'delete from user_location;' | su - postgres -c 'psql hfs'

Remove a RAID 1

The first step is to deactivate and remove the volume group:

vgchange -a n data
vgremove data

Then you have to actually deconstruct the RAID array and zero the superblock of each device:

mdadm --stop /dev/md0
mdadm --remove /dev/md0
mdadm --zero-superblock /dev/sda2
mdadm --zero-superblock /dev/sdb2

If you want to erase the remaining ext4 filesystem on thoses devices, you can use fdisk.