Commit Graph

5 Commits

Author SHA1 Message Date
rnhmjoj
5ea4160b33
treewide: fixup bcf54ce
fix the executable bit for scripts installed with substituteAll
and some remaining shebangs.
2019-04-12 09:09:22 +02:00
lewo
a8beff987d
Merge pull request #58350 from xtruder/pkgs/dockerTools/storePathToLayer/runtimeShell
dockerTools: storePathToLayer use runtimeShell in script
2019-04-06 19:01:19 +02:00
Alex Biehl
096e3cbdec Add /nix/store to each layer.tar
To be totally consistent with the way Docker builds images we need to
include the /nix/store in the layer tarballs first.
2019-03-27 11:35:27 +01:00
Jaka Hudoklin
5d429f6822
dockerTools: storePathToLayer use runtimeShell in script 2019-03-26 11:07:24 +01:00
Graham Christensen
4fe9006190 dockerTools.buildLayeredImage: init
Create a many-layered Docker Image.

Implements much less than buildImage:

 - Doesn't support specific uids/gids
 - Doesn't support runninng commands after building
 - Doesn't require qemu
 - Doesn't create mutable copies of the files in the path
 - Doesn't support parent images

If you want those feature, I recommend using buildLayeredImage as an
input to buildImage.

Notably, it does support:

 - Caching low level, common paths based on a graph traversial
   algorithm, see referencesByPopularity in
   0a80233487993256e811f566b1c80a40394c03d6
 - Configurable number of layers. If you're not using AUFS or not
   extending the image, you can specify a larger number of layers at
   build time:

       pkgs.dockerTools.buildLayeredImage {
         name = "hello";
         maxLayers = 128;
         config.Cmd = [ "${pkgs.gitFull}/bin/git" ];
       };

 - Parallelized creation of the layers, improving build speed.
 - The contents of the image includes the closure of the configuration,
   so you don't have to specify paths in contents and config.

   With buildImage, paths referred to by the config were not included
   automatically in the image. Thus, if you wanted to call Git, you
   had to specify it twice:

       pkgs.dockerTools.buildImage {
         name = "hello";
         contents = [ pkgs.gitFull ];
         config.Cmd = [ "${pkgs.gitFull}/bin/git" ];
       };

   buildLayeredImage on the other hand includes the runtime closure of
   the config when calculating the contents of the image:

       pkgs.dockerTools.buildImage {
         name = "hello";
         config.Cmd = [ "${pkgs.gitFull}/bin/git" ];
       };

Minor Problems

 - If any of the store paths change, every layer will be rebuilt in
   the nix-build. However, beacuse the layers are bit-for-bit
   reproducable, when these images are loaded in to Docker they will
   match existing layers and not be imported or uploaded twice.

Common Questions

 - Aren't Docker layers ordered?

   No. People who have used a Dockerfile before assume Docker's
   Layers are inherently ordered. However, this is not true -- Docker
   layers are content-addressable and are not explicitly layered until
   they are composed in to an Image.

 - What happens if I have more than maxLayers of store paths?

   The first (maxLayers-2) most "popular" paths will have their own
   individual layers, then layer #(maxLayers-1) will contain all the
   remaining "unpopular" paths, and finally layer #(maxLayers) will
   contain the Image configuration.
2018-09-26 17:54:14 -04:00