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 15 hours ago f35f0880f2c nixos/trunk-combined/tested
nixos-unstable-small 6 hours ago 9addfc003fb nixos/unstable-small/tested
nixpkgs-unstable 16 hours ago 4b0508a5853 nixpkgs/trunk/unstable
nixos-19.09 16 hours ago 80b42e630b2 nixos/release-19.09/tested
nixos-19.09-small 4 hours ago 02351ddb3a5 nixos/release-19.09-small/tested
nixpkgs-19.09-darwin 11 hours ago f6dac808387 nixpkgs/nixpkgs-19.09-darwin/darwin-tested
nixos-19.03 14 hours ago 9584ce65b7c nixos/release-19.03/tested
nixos-19.03-small 18 hours ago 8cc0abc1430 nixos/release-19.03-small/tested
nixpkgs-19.03-darwin 16 hours ago 8cc0abc1430 nixpkgs/nixpkgs-19.03-darwin/darwin-tested
nixos-18.09 155 days ago a7e559a5504 nixos/release-18.09/tested
nixos-18.09-small 156 days ago a7e559a5504 nixos/release-18.09-small/tested
nixpkgs-18.09-darwin 19 days ago f0b18a3f96f nixpkgs/nixpkgs-18.09-darwin/darwin-tested
nixos-18.03 244 days ago cb0e20d6db9 nixos/release-18.03/tested
nixos-18.03-small 84 days ago 4d48e8106f9 nixos/release-18.03-small/tested
nixpkgs-18.03-darwin 84 days ago 4d48e8106f9 nixpkgs/nixpkgs-18.03-darwin/darwin-tested
nixos-17.09 402 days ago 14f9ee66e63 nixos/release-17.09/tested
nixos-17.09-small 387 days ago 24a7883c234 nixos/release-17.09-small/tested
nixpkgs-17.09-darwin 387 days ago 24a7883c234 nixpkgs/nixpkgs-17.09-darwin/darwin-tested
nixos-17.03 606 days ago 78e9665b48f nixos/release-17.03/tested
nixos-17.03-small 562 days ago 2c1838ab99b nixos/release-17.03-small/tested
nixos-16.09 881 days ago 25f4906da6 nixos/release-16.09/tested
nixos-16.09-small 882 days ago 25f4906da6 nixos/release-16.09-small/tested
nixos-16.03 934 days ago dda40aa8d1 nixos/release-16.03/tested
nixos-16.03-small 934 days ago dda40aa8d1 nixos/release-16.03-small/tested
nixos-15.09 1045 days ago 3727911 nixos/release-15.09/tested
nixos-15.09-small 1046 days ago 3727911 nixos/release-15.09-small/tested
nixos-14.12 1483 days ago b373bf9 nixos/release-14.12/tested
nixos-14.12-small 1323 days ago c191689 nixos/release-14.12-small/tested
nixos-14.04 1517 days ago 8a3eea0 nixos/release-14.04/tested
nixos-14.04-small 1517 days ago 8a3eea0 nixos/release-14.04-small/tested
nixos-13.10 1853 days ago 91e952a nixos/release-13.10/tested

API | Made by Georges Dubus, code is on github