diff options
Diffstat (limited to 'nixos')
| -rw-r--r-- | nixos/modules/virtualisation/docker-preloader.nix | 135 | ||||
| -rw-r--r-- | nixos/modules/virtualisation/qemu-vm.nix | 5 | ||||
| -rw-r--r-- | nixos/release.nix | 1 | ||||
| -rw-r--r-- | nixos/tests/docker-preloader.nix | 27 |
4 files changed, 167 insertions, 1 deletions
diff --git a/nixos/modules/virtualisation/docker-preloader.nix b/nixos/modules/virtualisation/docker-preloader.nix new file mode 100644 index 000000000000..faa94f53d98f --- /dev/null +++ b/nixos/modules/virtualisation/docker-preloader.nix @@ -0,0 +1,135 @@ +{ config, lib, pkgs, ... }: + +with lib; +with builtins; + +let + cfg = config.virtualisation; + + sanitizeImageName = image: replaceStrings ["/"] ["-"] image.imageName; + hash = drv: head (split "-" (baseNameOf drv.outPath)); + # The label of an ext4 FS is limited to 16 bytes + labelFromImage = image: substring 0 16 (hash image); + + # The Docker image is loaded and some files from /var/lib/docker/ + # are written into a qcow image. + preload = image: pkgs.vmTools.runInLinuxVM ( + pkgs.runCommand "docker-preload-image-${sanitizeImageName image}" { + buildInputs = with pkgs; [ docker e2fsprogs utillinux curl kmod ]; + preVM = pkgs.vmTools.createEmptyImage { + size = cfg.dockerPreloader.qcowSize; + fullName = "docker-deamon-image.qcow2"; + }; + } + '' + mkfs.ext4 /dev/vda + e2label /dev/vda ${labelFromImage image} + mkdir -p /var/lib/docker + mount -t ext4 /dev/vda /var/lib/docker + + modprobe overlay + + # from https://github.com/tianon/cgroupfs-mount/blob/master/cgroupfs-mount + mount -t tmpfs -o uid=0,gid=0,mode=0755 cgroup /sys/fs/cgroup + cd /sys/fs/cgroup + for sys in $(awk '!/^#/ { if ($4 == 1) print $1 }' /proc/cgroups); do + mkdir -p $sys + if ! mountpoint -q $sys; then + if ! mount -n -t cgroup -o $sys cgroup $sys; then + rmdir $sys || true + fi + fi + done + + dockerd -H tcp://127.0.0.1:5555 -H unix:///var/run/docker.sock & + + until $(curl --output /dev/null --silent --connect-timeout 2 http://127.0.0.1:5555); do + printf '.' + sleep 1 + done + + docker load -i ${image} + + kill %1 + find /var/lib/docker/ -maxdepth 1 -mindepth 1 -not -name "image" -not -name "overlay2" | xargs rm -rf + ''); + + preloadedImages = map preload cfg.dockerPreloader.images; + +in + +{ + options.virtualisation.dockerPreloader = { + images = mkOption { + default = [ ]; + type = types.listOf types.package; + description = + '' + A list of Docker images to preload (in the /var/lib/docker directory). + ''; + }; + qcowSize = mkOption { + default = 1024; + type = types.int; + description = + '' + The size (MB) of qcow files. + ''; + }; + }; + + config = { + assertions = [{ + # If docker.storageDriver is null, Docker choose the storage + # driver. So, in this case, we cannot be sure overlay2 is used. + assertion = cfg.dockerPreloader.images == [] + || cfg.docker.storageDriver == "overlay2" + || cfg.docker.storageDriver == "overlay" + || cfg.docker.storageDriver == null; + message = "The Docker image Preloader only works with overlay2 storage driver!"; + }]; + + virtualisation.qemu.options = + map (path: "-drive if=virtio,file=${path}/disk-image.qcow2,readonly,media=cdrom,format=qcow2") + preloadedImages; + + + # All attached QCOW files are mounted and their contents are linked + # to /var/lib/docker/ in order to make image available. + systemd.services.docker-preloader = { + description = "Preloaded Docker images"; + wantedBy = ["docker.service"]; + after = ["network.target"]; + path = with pkgs; [ mount rsync jq ]; + script = '' + mkdir -p /var/lib/docker/overlay2/l /var/lib/docker/image/overlay2 + echo '{}' > /tmp/repositories.json + + for i in ${concatStringsSep " " (map labelFromImage cfg.dockerPreloader.images)}; do + mkdir -p /mnt/docker-images/$i + + # The ext4 label is limited to 16 bytes + mount /dev/disk/by-label/$(echo $i | cut -c1-16) -o ro,noload /mnt/docker-images/$i + + find /mnt/docker-images/$i/overlay2/ -maxdepth 1 -mindepth 1 -not -name l\ + -exec ln -s '{}' /var/lib/docker/overlay2/ \; + cp -P /mnt/docker-images/$i/overlay2/l/* /var/lib/docker/overlay2/l/ + + rsync -a /mnt/docker-images/$i/image/ /var/lib/docker/image/ + + # Accumulate image definitions + cp /tmp/repositories.json /tmp/repositories.json.tmp + jq -s '.[0] * .[1]' \ + /tmp/repositories.json.tmp \ + /mnt/docker-images/$i/image/overlay2/repositories.json \ + > /tmp/repositories.json + done + + mv /tmp/repositories.json /var/lib/docker/image/overlay2/repositories.json + ''; + serviceConfig = { + Type = "oneshot"; + }; + }; + }; +} diff --git a/nixos/modules/virtualisation/qemu-vm.nix b/nixos/modules/virtualisation/qemu-vm.nix index 4e9c87222d0a..ed3431554be4 100644 --- a/nixos/modules/virtualisation/qemu-vm.nix +++ b/nixos/modules/virtualisation/qemu-vm.nix @@ -185,7 +185,10 @@ let in { - imports = [ ../profiles/qemu-guest.nix ]; + imports = [ + ../profiles/qemu-guest.nix + ./docker-preloader.nix + ]; options = { diff --git a/nixos/release.nix b/nixos/release.nix index 51505d6aab9d..2bd70f7962fe 100644 --- a/nixos/release.nix +++ b/nixos/release.nix @@ -283,6 +283,7 @@ in rec { tests.docker-tools = callTestOnMatchingSystems ["x86_64-linux"] tests/docker-tools.nix {}; tests.docker-tools-overlay = callTestOnMatchingSystems ["x86_64-linux"] tests/docker-tools-overlay.nix {}; tests.docker-edge = callTestOnMatchingSystems ["x86_64-linux"] tests/docker-edge.nix {}; + tests.docker-preloader = callTestOnMatchingSystems ["x86_64-linux"] tests/docker-preloader.nix {}; tests.docker-registry = callTest tests/docker-registry.nix {}; tests.dovecot = callTest tests/dovecot.nix {}; tests.dnscrypt-proxy = callTestOnMatchingSystems ["x86_64-linux"] tests/dnscrypt-proxy.nix {}; diff --git a/nixos/tests/docker-preloader.nix b/nixos/tests/docker-preloader.nix new file mode 100644 index 000000000000..eeedec9a392e --- /dev/null +++ b/nixos/tests/docker-preloader.nix @@ -0,0 +1,27 @@ +import ./make-test.nix ({ pkgs, ...} : { + name = "docker-preloader"; + meta = with pkgs.stdenv.lib.maintainers; { + maintainers = [ lewo ]; + }; + + nodes = { + docker = + { pkgs, ... }: + { + virtualisation.docker.enable = true; + virtualisation.dockerPreloader.images = [ pkgs.dockerTools.examples.nix pkgs.dockerTools.examples.bash ]; + + services.openssh.enable = true; + services.openssh.permitRootLogin = "yes"; + services.openssh.extraConfig = "PermitEmptyPasswords yes"; + users.extraUsers.root.password = ""; + }; + }; + testScript = '' + startAll; + + $docker->waitForUnit("sockets.target"); + $docker->succeed("docker run nix nix-store --version"); + $docker->succeed("docker run bash bash --version"); + ''; +}) |