3b0d5b5ed3
Adapted from grahamc's blog post on layered Docker images in Nix: https://grahamc.com/blog/nix-and-layered-docker-images
237 lines
6.2 KiB
Nix
237 lines
6.2 KiB
Nix
# Examples of using the docker tools to build packages.
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#
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# This file defines several docker images. In order to use an image,
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# build its derivation with `nix-build`, and then load the result with
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# `docker load`. For example:
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#
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# $ nix-build '<nixpkgs>' -A dockerTools.examples.redis
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# $ docker load < result
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{ pkgs, buildImage, pullImage, shadowSetup, buildImageWithNixDb }:
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rec {
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# 1. basic example
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bash = buildImage {
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name = "bash";
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tag = "latest";
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contents = pkgs.bashInteractive;
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};
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# 2. service example, layered on another image
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redis = buildImage {
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name = "redis";
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tag = "latest";
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# for example's sake, we can layer redis on top of bash or debian
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fromImage = bash;
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# fromImage = debian;
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contents = pkgs.redis;
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runAsRoot = ''
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mkdir -p /data
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'';
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config = {
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Cmd = [ "/bin/redis-server" ];
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WorkingDir = "/data";
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Volumes = {
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"/data" = {};
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};
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};
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};
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# 3. another service example
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nginx = let
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nginxPort = "80";
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nginxConf = pkgs.writeText "nginx.conf" ''
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user nginx nginx;
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daemon off;
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error_log /dev/stdout info;
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pid /dev/null;
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events {}
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http {
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access_log /dev/stdout;
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server {
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listen ${nginxPort};
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index index.html;
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location / {
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root ${nginxWebRoot};
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}
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}
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}
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'';
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nginxWebRoot = pkgs.writeTextDir "index.html" ''
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<html><body><h1>Hello from NGINX</h1></body></html>
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'';
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in
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buildImage {
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name = "nginx-container";
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tag = "latest";
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contents = pkgs.nginx;
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runAsRoot = ''
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#!${pkgs.stdenv.shell}
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${shadowSetup}
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groupadd --system nginx
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useradd --system --gid nginx nginx
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'';
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config = {
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Cmd = [ "nginx" "-c" nginxConf ];
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ExposedPorts = {
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"${nginxPort}/tcp" = {};
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};
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};
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};
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# 4. example of pulling an image. could be used as a base for other images
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nixFromDockerHub = pullImage {
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imageName = "nixos/nix";
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imageDigest = "sha256:85299d86263a3059cf19f419f9d286cc9f06d3c13146a8ebbb21b3437f598357";
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sha256 = "07q9y9r7fsd18sy95ybrvclpkhlal12d30ybnf089hq7v1hgxbi7";
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finalImageTag = "2.2.1";
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finalImageName = "nix";
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};
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# 5. example of multiple contents, emacs and vi happily coexisting
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editors = buildImage {
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name = "editors";
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contents = [
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pkgs.coreutils
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pkgs.bash
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pkgs.emacs
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pkgs.vim
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pkgs.nano
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];
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};
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# 6. nix example to play with the container nix store
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# docker run -it --rm nix nix-store -qR $(nix-build '<nixpkgs>' -A nix)
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nix = buildImageWithNixDb {
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name = "nix";
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tag = "latest";
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contents = [
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# nix-store uses cat program to display results as specified by
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# the image env variable NIX_PAGER.
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pkgs.coreutils
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pkgs.nix
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];
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config = {
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Env = [ "NIX_PAGER=cat" ];
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};
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};
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# 7. example of adding something on top of an image pull by our
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# dockerTools chain.
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onTopOfPulledImage = buildImage {
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name = "onTopOfPulledImage";
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tag = "latest";
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fromImage = nixFromDockerHub;
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contents = [ pkgs.hello ];
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};
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# 8. regression test for erroneous use of eval and string expansion.
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# See issue #34779 and PR #40947 for details.
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runAsRootExtraCommands = pkgs.dockerTools.buildImage {
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name = "runAsRootExtraCommands";
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tag = "latest";
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contents = [ pkgs.coreutils ];
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# The parens here are to create problematic bash to embed and eval. In case
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# this is *embedded* into the script (with nix expansion) the initial quotes
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# will close the string and the following parens are unexpected
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runAsRoot = ''echo "(runAsRoot)" > runAsRoot'';
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extraCommands = ''echo "(extraCommand)" > extraCommands'';
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};
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# 9. Ensure that setting created to now results in a date which
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# isn't the epoch + 1
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unstableDate = pkgs.dockerTools.buildImage {
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name = "unstable-date";
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tag = "latest";
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contents = [ pkgs.coreutils ];
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created = "now";
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};
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# 10. Create a layered image
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layered-image = pkgs.dockerTools.buildLayeredImage {
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name = "layered-image";
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tag = "latest";
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extraCommands = ''echo "(extraCommand)" > extraCommands'';
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config.Cmd = [ "${pkgs.hello}/bin/hello" ];
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contents = [ pkgs.hello pkgs.bash pkgs.coreutils ];
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};
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# 11. Create an image on top of a layered image
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layered-on-top = pkgs.dockerTools.buildImage {
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name = "layered-on-top";
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tag = "latest";
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fromImage = layered-image;
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extraCommands = ''
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mkdir ./example-output
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chmod 777 ./example-output
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'';
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config = {
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Env = [ "PATH=${pkgs.coreutils}/bin/" ];
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WorkingDir = "/example-output";
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Cmd = [
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"${pkgs.bash}/bin/bash" "-c" "echo hello > foo; cat foo"
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];
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};
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};
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# 12. example of running something as root on top of a parent image
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# Regression test related to PR #52109
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runAsRootParentImage = buildImage {
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name = "runAsRootParentImage";
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tag = "latest";
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runAsRoot = "touch /example-file";
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fromImage = bash;
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};
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# 13. example of 3 layers images This image is used to verify the
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# order of layers is correct.
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# It allows to validate
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# - the layer of parent are below
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# - the order of parent layer is preserved at image build time
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# (this is why there are 3 images)
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layersOrder = let
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l1 = pkgs.dockerTools.buildImage {
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name = "l1";
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tag = "latest";
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extraCommands = ''
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mkdir -p tmp
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echo layer1 > tmp/layer1
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echo layer1 > tmp/layer2
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echo layer1 > tmp/layer3
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'';
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};
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l2 = pkgs.dockerTools.buildImage {
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name = "l2";
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fromImage = l1;
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tag = "latest";
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extraCommands = ''
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mkdir -p tmp
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echo layer2 > tmp/layer2
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echo layer2 > tmp/layer3
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'';
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};
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in pkgs.dockerTools.buildImage {
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name = "l3";
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fromImage = l2;
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tag = "latest";
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contents = [ pkgs.coreutils ];
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extraCommands = ''
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mkdir -p tmp
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echo layer3 > tmp/layer3
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'';
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};
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# 14. Create another layered image, for comparing layers with image 10.
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another-layered-image = pkgs.dockerTools.buildLayeredImage {
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name = "another-layered-image";
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tag = "latest";
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config.Cmd = [ "${pkgs.hello}/bin/hello" ];
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contents = [ pkgs.hello ];
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};
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}
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