Agenda

• Nix terminology (http://nixos.org/)
  • Nix, the package manager and programming language
  • Nixpkgs, the package collection
  • NixOS, the operating system
• Ceh (http://github.com/errge/ceh/)
  • the Git synchronized, sharable and reproducible power-user environment based on Nix and Nixpkgs
• Nix details. Nix language example: vanitygen
• Ceh details. Wrapper for tmux, ldd
• Haskell integration, included tools, deploying binaries
• Travis thyme
• Summary, what to do with this?

Nix, Nixpkgs, NixOS

• Nix: a lazy and pure language to describe software build instructions (like debian/rules) and the corresponding package manager to execute these instructions (like dpkg, but more like Gentoo with binary cache).
  https://github.com/NixOS/nix/

• Nixpkgs: a package collection with ~9000 packages.
  https://github.com/NixOS/nixpkgs/

• Nixpkgs is continuously built using hydra.
  http://hydra.nixos.org/

• NixOS: Linux distribution based on Nix.

NixOS screenshot 1/2

NixOS grub menu, note the different configurations! You can boot the system at a specific version by just choosing from GRUB.

NixOS screenshot 2/2

NixOS goals

• Reliable, atomic upgrades and rollbacks,

• reproducible systems,

• buildable from source, but have a binary cache,

• consistency (e.g. security upgrades work even if you link statically against a library),

• package management even for non-root users.

Ceh goals

• Reproducible distribution of packages (power-user envs):
  • GHC with batteries, best possible GHC experience,
  • Firefox with running Java, Flash and Google Hangouts,
  • fresh Emacs,
  • whatever else you want and help with it, :)
• upgrades/rollbacks via Git, synchronization via Github,
• on top of any modern GNU/Linux distro,
• on both i686 and amd64 machines,
• convenient (no chroots or VMs that you have to log into),
• /opt/ceh/home, /opt/ceh/p/myproject; we are single-user anyways.

Nix details

• Store every installed package in a subdir inside /nix/store,
  • subdir name based on the hash of all the build inputs,
  • different versions/configurations of a package can be installed,
• hack the build environment and makefiles of packages to behave in /nix/store in a pure way: no random picking up of dependencies from /usr/lib or /usr/include, Nix is the language to describe this procedure (demo: https://github.com/NixOS/nixpkgs/blob/master/pkgs/applications/misc/vanitygen/default.nix)
• hack the installed binaries to have everything correctly RPATHed (demo: patchelf --print-rpath /nix/store/.../tmux and ldd),
• binary cache based on the output hashes,
• symlink farms (so called profiles) for a unixish view (next slide),
• can be used without NixOS.

Nix details

Ceh details

• Just a bunch of scripts to make handling of Nix convenient on a standard GNU/Linux workstation,
• root needed only for installation:

sudo mkdir /opt/ceh /nix
sudo chown $USER. /opt/ceh /nix
chmod 0700 /opt/ceh /nix
cd /opt/ceh
git clone git://github.com/errge/ceh.git .
ln -s $HOME home
/opt/ceh/scripts/ceh-init.sh

• single user, but we get /opt/ceh/home and /opt/ceh/p,
  • if you're really worried, look into LXC mount namespaces,
  • but don't hold onto your abstractions if you don't need them anymore,
• /opt/ceh/bin goes to your PATH and /opt/ceh/bin/tmux installs tmux on-demand.

Haskell integration, included tools

• Since we use Haskell a lot, it's very well supported, full featured:
  • GHC in 32 and 64-bit mode,
  • with all the Platform libraries,
  • with a lot of extra libraries (e.g. lens, gtk, pipes),
  • everything built with profiling possibility,
  • hoogle with local data indexing for all the installed libraries,
  • ghc-vis and ghc-heapview,
  • ghc-mod for Emacs,
  • all coming from the Nix binary cache, so it's quick to install,
• documented way to compile 32 or 64-bit GHC (no more VMs).

Deploying compiled binaries

• Documented way to deploy Ceh compiled haskell binaries:
  • just gather the needed .so files from /nix/store,
  • put them in a lib/ directory,
  • use patchelf to redirect RPATHs to point there,
  • deploy binary+lib/ combination to any system even without Ceh.

errge@curry:/tmp/deploy $ ldd ./PrefetchFS ; du -sh
  linux-gate.so.1 (0xf778a000)
  libfuse.so.2 => /tmp/deploy/./lib/libfuse.so.2 (0xf7754000)
  librt.so.1 => /tmp/deploy/./lib/librt.so.1 (0xf774c000)
  libutil.so.1 => /tmp/deploy/./lib/libutil.so.1 (0xf7747000)
  libdl.so.2 => /tmp/deploy/./lib/libdl.so.2 (0xf7743000)
  libgmp.so.10 => /tmp/deploy/./lib/libgmp.so.10 (0xf76c8000)
  libm.so.6 => /tmp/deploy/./lib/libm.so.6 (0xf768a000)
  libpthread.so.0 => /tmp/deploy/./lib/libpthread.so.0 (0xf7671000)
  libc.so.6 => /tmp/deploy/./lib/libc.so.6 (0xf74da000)
  /lib/ld-linux.so.2 (0xf778b000)
4.3M    .

Travis thyme

https://travis-ci.org/errge/thyme

.travis.yml, .travis.ceh:

language: c
install: bash ./.travis.ceh
script: bash ./.travis.main
env:
  - CEH_GHC64=
  - CEH_GHC64=1

#!/bin/bash -e

sudo mkdir /opt/ceh /nix
sudo chown $USER. /opt/ceh /nix
chmod 0700 /opt/ceh /nix
cd /opt/ceh
git clone git://github.com/errge/ceh.git .
ln -s $HOME home
/opt/ceh/scripts/ceh-init.sh

Travis thyme

https://travis-ci.org/errge/thyme

.travis.main:

#!/bin/bash -e

. /opt/ceh/scripts/ceh-profile.sh

cabal update
cabal install --only-dependencies
cabal configure --user --enable-tests
cabal build
cabal test

Summary, where to go from here

So, how to use all this, where to go from here?

• Option 1, live with my governance regarding ceh and:
  • check out, install, try, periodically pull for new things,
  • send pull requests for missing stuff,
  • if I turn evil, just revert to a good state in Git and fork.
• Option 2, commercial setting or just a little bit paranoid:
  • fork me on Github,
  • and maintain your own version for your own company/whatever,
  • merge here and there.
• Option 3, meh, I'm not interested:
  • remember the novel, interesting way how Nix applied the concepts of purity, immutability, and lazyness to the software configuration world.

Thank you

Questions, remarks?

I'm also available during the Zurihac to answer your questions or help with installing/using/abusing Ceh.

http://github.com/errge/ceh