Chaos Bernie implements Azure as an external process source for psDoom-ng.

Warning Azure resources will be permanently and irrevocably destroyed: use at your own risk!

Background

• 1997: id Software release source code to DOOM
• 1999: psDoom origins and proof of concept - Doom as a tool for system administration
• 2000: psDoom released

  psDooM is a process monitor and manager for *nix systems. It could be considered a graphical interface to the 'ps', 'renice', and 'kill' commands. psDooM is based on XDoom, which is based on id Software's 'Doom'.

• 2016: psDoom-ng released, updating psDoom for modern operating systems and support for external process source

  psdoom-ng is a First Person Shooter operating system process killer based on psDooM and Chocolate Doom.

• 2022: Chaos Bernie written to add Azure virtual machines and resource groups as external processes

Chaos Bernie

Chaos Bernie was written during an internal hackathon as a fun way to clean up Azure resources. Users are great at spinning up compute resources but often require nagging to deallocate or destroy them. As Bernie would say "Once again I'm asking for you to clean up your compute resources"

Chaos Bernie adds Azure virtual machines and resource groups as external process to psDoom-ng.

As per the psDoom-ng documentation, DOOM is a single threaded application so any blocking on external scripts makes the game unplayable. Azure resources take a while to delete so golang was chosen for concurrency and unix domain sockets for a simple queue for client to communicate with backend.

This could easily be adapted to other cloud providers (AWS, GCP)

Architecture

Interaction with psDoom via external process sources https://github.com/yeoldegrove/psdoom-ng1#support-for-external-process-source

Three commands with their required inputs/outputs

• PSDOOMPSCMD
  • The command must print one space separated line per process with the format:

    <user> <pid> <processname> <is_daemon=[1|0]>
    

• PSDOOMRENICECMD
  • input: PID
• PSDOOMKILLCMD
  • input: PID

For Azure, these values have the following definitions

Variable	Azure Definition
user	resource group
pid	unique integer generated from JSON array element ID + 100
processname	resource name
is_daemon	deallocate (1), delete (0)

The wrapper script cb.sh populates the environment variables for PSDOOM with azure/bin/client with the appropriate flags.

PSDOOMPSCMD="${SCRIPT_DIR}/azure/bin/client --action=ps"
PSDOOMRENICECMD="${SCRIPT_DIR}/azure/bin/client --action=renice"
PSDOOMKILLCMD="${SCRIPT_DIR}/azure/bin/client --action=kill"

(It may be necessary to run psd in psdoom-ng's source directory once before chaos bernie will run)

Modes

There are two modes

• deallocate: stops and deallocate the virtual machine resources (virtual machines only). In the process list, resources to be deallocated are represented as 'daemons' and killing them in game will trigger the 'renice' command
• destroy: destroys the resource (resource groups, virtual machines). These are 'processes' aka zombie man in the process list and killing them in game runs the 'kill' command

Interaction with Azure APIs

Azure APIs and the golang Azure SDK are a bit of a mess. The lazy option was chosen to just interface with the Azure CLI az over using SDKs

A static JSON file generated from Azure Graph queries is used to provide input of 'processes'. The main reason for is it is called frequently by psDoom-ng and any blocking to list live resources won't be tolerated by the game. Doing this as a static file also allow sanity checking of resources before they are permanently and irrevocably destroyed

Visualisation

To help visualise the status of the Azure resources, the generation of graphviz DOT file was added. xdot can render this and will update display when file is changed on disk

Setup

The following has been tested on Ubuntu 20.04

Compile psDoom-ng

if not already installed, packages required to compile everything

apt install git build-essential autoconf golang python3-pip

install psdoom-ng specific requirements

apt install libsdl1.2-dev libsdl-mixer1.2-dev libsdl-net1.2-dev

clone psdoomr-ng repo

git clone https://github.com/yeoldegrove/psdoom-ng1

compile psdoom-ng

./autogen.sh
make
sudo make install

Setup DOOM and remap keyboard to WASD

psdoom-setup

Doom WAD

From Wikipedia https://en.wikipedia.org/wiki/Doom_modding

Doom WAD is the default format of package files for the video game Doom and its sequel Doom II: Hell on Earth, that contain sprites, levels, and game data. WAD stands for Where's All the Data?

WAD files are not included with the released source code. If you own DOOM (available on Steam) you can use the WAD files distributed with the game. Alternatively you can use the shareware WAD

apt install doom-wad-shareware

Setup Chaos Bernie

install Azure CLI

pip3 install az-cli
export PATH=$PATH:~/.local/bin/
az login --use-device-code

using device code, you can login via host computer

to render dot files for scoreboard

apt install xdot

compile client and server applications

(cd azure && make)

Run Chaos Bernie

Generate resource/process list

Using Azure Graph we can generate JSON files with list of 'processes' to include in the game for deallocation or deletion. It's up to you what to include here but some sample queries. Only virtual machines and resource groups have been tested but likely other Azure resource types will work without any modification

Note There is no concurrency limit or queuing beyond domain socket, if you attempt to kill too many monsters at once it may lock up the game/computer or make game unplayable** e.g. running Chaos Bernie with 120 VMs and using the rocket launcher on the monsters crashed the test VM running DOOM.

Running virtual machines:

az graph query -q "Resources
| where type =~ 'microsoft.compute/virtualmachines'
| where properties.extended.instanceView.powerState.code has 'running'
" --query 'data' > virtual-machines.json

Resource groups:

az graph query -q 'resourcecontainers
| where type == "microsoft.resources/subscriptions/resourcegroups"
' --query 'data' > resource-groups.json

Server

Server usage

./azure/bin/server --help
Usage:
  server [OPTIONS]

Application Options:
  -f, --file=FILE                     JSON file with resources
      --action=[deallocate|delete]
      --socket=                       unix domain socket to create, defaults to
                                      ~/.chaosbernie.sock
  -d, --debug
      --dry-run

Help Options:
  -h, --help                          Show this help message

start the server with minimum required options

./azure/bin/server -f ./virtual-machines.json

Visualiser

To view visualisation while playing, you will need to use psdoom-ng-setup to configure DOOM to run in window mode

start xdot in background

xdot resources.gv & 

Legend:

Colour	Meaning
Blue	hierarchy/grouping (e.g. for virtual machines, which resource group they belong to)
Green	resource that is represented by monster in game
Orange	monster has been shot and azure operation has been triggered
Red	Azure operation complete, resource deleted/deallocated

Client

start psdoom-ng

./cb.sh

additional options can be passed through to psdoom-ng, e.g.

./cb.sh -godstart -telestartf 136310834 -257677815

which will start in god mode (iddqd) and teleport you directly to the steps outside the hidden area

Demo

chaosbernie_demo.mp4