How does channel update?

Anyone with commit access can push changes to either master or one of the release-XX.XX branches.

Each channel has an associated jobset on Hydra (Nix CI) that is a collection of individual jobs. A job roughly corresponds to building a particular package, which itself may depend on other packages built by other jobs.

Before a channel can update, its associated jobset must be finished building, though the building of some jobs may fail.

As long as certain special jobs -- unstable for nixpkgs, and tested for nixos -- build successfully, the channel can update. The role of these special jobs is to ensure that essential functionality is present on each channel update.

There are two major differences between those jobsets:

  • nixpkgs-unstable
    • builds all packages for supported platforms (Linux, Darwin)
    • unstable job that consists of most commonly used packages
  • nixos-*
    • builds all packages and NixOS machinery only for Linux
    • tested job that consists of mostly NixOS tests firing up qemu instances with different kinds of configurations

For a channel to be updated two conditions need to be satisfied:

  • Particular jobset evaluation needs to be completely built ie. no more queued jobs, even if some jobs may fail
  • Particular jobset evaluation's tested/unstable job needs to be built succesfully

The nixos.org server has a cronjob for which nixos-channel-scripts are executed and poll for the newest jobset that satisfies the above two conditions and trigger a channel update.

Once triggered, release files such as ISOs are copied. For the NixOS channel command-not-found index is generated, which can take some time since it has to fetch all packages.

nixpkgs is quickly updated since none of the above needs to happen once a channel update is triggered.

Channel Last updated Commit Hydra job for tests
nixos-unstable 4 days ago 45a419ab5a2 nixos/trunk-combined/tested
nixos-unstable-small 4 hours ago 80906eb858e nixos/unstable-small/tested
nixpkgs-unstable 2 days ago ac7bf94f6df nixpkgs/trunk/unstable
nixos-18.09 2 days ago 09195057114 nixos/release-18.09/tested
nixos-18.09-small 2 hours ago 0da77aaaf82 nixos/release-18.09-small/tested
nixpkgs-18.09-darwin 3 hours ago 720af0f20fb nixpkgs/nixpkgs-18.09-darwin/darwin-tested
nixos-18.03 5 days ago 5d19e3e78fb nixos/release-18.03/tested
nixos-18.03-small 5 hours ago d3be52c83bf nixos/release-18.03-small/tested
nixpkgs-18.03-darwin 1 day ago 43631e2b01b nixpkgs/nixpkgs-18.03-darwin/darwin-tested
nixos-17.09 36 days ago 14f9ee66e63 nixos/release-17.09/tested
nixos-17.09-small 21 days ago 24a7883c234 nixos/release-17.09-small/tested
nixpkgs-17.09-darwin 21 days ago 24a7883c234 nixpkgs/nixpkgs-17.09-darwin/darwin-tested
nixos-17.03 239 days ago 78e9665b48f nixos/release-17.03/tested
nixos-17.03-small 196 days ago 2c1838ab99b nixos/release-17.03-small/tested
nixos-16.09 515 days ago 25f4906da6 nixos/release-16.09/tested
nixos-16.09-small 515 days ago 25f4906da6 nixos/release-16.09-small/tested
nixos-16.03 568 days ago dda40aa8d1 nixos/release-16.03/tested
nixos-16.03-small 568 days ago dda40aa8d1 nixos/release-16.03-small/tested
nixos-15.09 679 days ago 3727911 nixos/release-15.09/tested
nixos-15.09-small 679 days ago 3727911 nixos/release-15.09-small/tested
nixos-14.12 1116 days ago b373bf9 nixos/release-14.12/tested
nixos-14.12-small 956 days ago c191689 nixos/release-14.12-small/tested
nixos-14.04 1150 days ago 8a3eea0 nixos/release-14.04/tested
nixos-14.04-small 1150 days ago 8a3eea0 nixos/release-14.04-small/tested
nixos-13.10 1486 days ago 91e952a nixos/release-13.10/tested

API | Made by Georges Dubus, code is on github