6.3 Replicating Guix

The guix pull --list-generations output above shows precisely which commits were used to build this instance of Guix. We can thus replicate it, say, on another machine, by providing a channel specification in ~/.config/guix/channels.scm that is “pinned” to these commits:

;; Deploy specific commits of my channels of interest.
(list (channel
       (name 'guix)
       (url "https://git.savannah.gnu.org/git/guix.git")
       (commit "6298c3ffd9654d3231a6f25390b056483e8f407c"))
      (channel
       (name 'variant-packages)
       (url "https://example.org/variant-packages.git")
       (commit "dd3df5e2c8818760a8fc0bd699e55d3b69fef2bb")))

The guix describe --format=channels command can even generate this list of channels directly (see Invoking guix describe). The resulting file can be used with the -C options of guix pull (see Invoking guix pull) or guix time-machine (see Invoking guix time-machine).

At this point the two machines run the exact same Guix, with access to the exact same packages. The output of guix build gimp on one machine will be exactly the same, bit for bit, as the output of the same command on the other machine. It also means both machines have access to all the source code of Guix and, transitively, to all the source code of every package it defines.

This gives you super powers, allowing you to track the provenance of binary artifacts with very fine grain, and to reproduce software environments at will—some sort of “meta reproducibility” capabilities, if you will. See Inferiors, for another way to take advantage of these super powers.