Merge pull request #106574 from grahamc/amazon-image-zfs

nixos/amazonImageZfs: init

nixos/lib/make-zfs-image.nix

@@ -0,0 +1,333 @@
+# Note: This is a private API, internal to NixOS. Its interface is subject
+# to change without notice.
+#
+# The result of this builder is two disk images:
+#
+#  * `boot` - a small disk formatted with FAT to be used for /boot. FAT is
+#    chosen to support EFI.
+#  * `root` - a larger disk with a zpool taking the entire disk.
+#
+# This two-disk approach is taken to satisfy ZFS's requirements for
+# autoexpand.
+#
+# # Why doesn't autoexpand work with ZFS in a partition?
+#
+# When ZFS owns the whole disk doesn’t really use a partition: it has
+# a marker partition at the start and a marker partition at the end of
+# the disk.
+#
+# If ZFS is constrained to a partition, ZFS leaves expanding the partition
+# up to the user. Obviously, the user may not choose to do so.
+#
+# Once the user expands the partition, calling zpool online -e expands the
+# vdev to use the whole partition. It doesn’t happen automatically
+# presumably because zed doesn’t get an event saying it’s partition grew,
+# whereas it can and does get an event saying the whole disk it is on is
+# now larger.
+{ lib
+, pkgs
+, # The NixOS configuration to be installed onto the disk image.
+  config
+
+, # size of the FAT boot disk, in megabytes.
+  bootSize ? 1024
+
+, # The size of the root disk, in megabytes.
+  rootSize ? 2048
+
+, # The name of the ZFS pool
+  rootPoolName ? "tank"
+
+, # zpool properties
+  rootPoolProperties ? {
+    autoexpand = "on";
+  }
+, # pool-wide filesystem properties
+  rootPoolFilesystemProperties ? {
+    acltype = "posixacl";
+    atime = "off";
+    compression = "on";
+    mountpoint = "legacy";
+    xattr = "sa";
+  }
+
+, # datasets, with per-attribute options:
+  # mount: (optional) mount point in the VM
+  # properties: (optional) ZFS properties on the dataset, like filesystemProperties
+  # Notes:
+  # 1. datasets will be created from shorter to longer names as a simple topo-sort
+  # 2. you should define a root's dataset's mount for `/`
+  datasets ? { }
+
+, # The files and directories to be placed in the target file system.
+  # This is a list of attribute sets {source, target} where `source'
+  # is the file system object (regular file or directory) to be
+  # grafted in the file system at path `target'.
+  contents ? []
+
+, # The initial NixOS configuration file to be copied to
+  # /etc/nixos/configuration.nix. This configuration will be embedded
+  # inside a configuration which includes the described ZFS fileSystems.
+  configFile ? null
+
+, # Shell code executed after the VM has finished.
+  postVM ? ""
+
+, name ? "nixos-disk-image"
+
+, # Disk image format, one of qcow2, qcow2-compressed, vdi, vpc, raw.
+  format ? "raw"
+
+, # Include a copy of Nixpkgs in the disk image
+  includeChannel ? true
+}:
+let
+  formatOpt = if format == "qcow2-compressed" then "qcow2" else format;
+
+  compress = lib.optionalString (format == "qcow2-compressed") "-c";
+
+  filenameSuffix = "." + {
+    qcow2 = "qcow2";
+    vdi = "vdi";
+    vpc = "vhd";
+    raw = "img";
+  }.${formatOpt} or formatOpt;
+  bootFilename = "nixos.boot${filenameSuffix}";
+  rootFilename = "nixos.root${filenameSuffix}";
+
+  # FIXME: merge with channel.nix / make-channel.nix.
+  channelSources =
+    let
+      nixpkgs = lib.cleanSource pkgs.path;
+    in
+      pkgs.runCommand "nixos-${config.system.nixos.version}" {} ''
+        mkdir -p $out
+        cp -prd ${nixpkgs.outPath} $out/nixos
+        chmod -R u+w $out/nixos
+        if [ ! -e $out/nixos/nixpkgs ]; then
+          ln -s . $out/nixos/nixpkgs
+        fi
+        rm -rf $out/nixos/.git
+        echo -n ${config.system.nixos.versionSuffix} > $out/nixos/.version-suffix
+      '';
+
+  closureInfo = pkgs.closureInfo {
+    rootPaths = [ config.system.build.toplevel ]
+    ++ (lib.optional includeChannel channelSources);
+  };
+
+  modulesTree = pkgs.aggregateModules
+    (with config.boot.kernelPackages; [ kernel zfs ]);
+
+  tools = lib.makeBinPath (
+    with pkgs; [
+      config.system.build.nixos-enter
+      config.system.build.nixos-install
+      dosfstools
+      e2fsprogs
+      gptfdisk
+      nix
+      parted
+      utillinux
+      zfs
+    ]
+  );
+
+  hasDefinedMount  = disk: ((disk.mount or null) != null);
+
+  stringifyProperties = prefix: properties: lib.concatStringsSep " \\\n" (
+    lib.mapAttrsToList
+      (
+        property: value: "${prefix} ${lib.escapeShellArg property}=${lib.escapeShellArg value}"
+      )
+      properties
+  );
+
+  featuresToProperties = features:
+    lib.listToAttrs
+      (builtins.map (feature: {
+        name = "feature@${feature}";
+        value = "enabled";
+      }) features);
+
+  createDatasets =
+    let
+      datasetlist = lib.mapAttrsToList lib.nameValuePair datasets;
+      sorted = lib.sort (left: right: (lib.stringLength left.name) < (lib.stringLength right.name)) datasetlist;
+      cmd = { name, value }:
+        let
+          properties = stringifyProperties "-o" (value.properties or {});
+        in
+          "zfs create -p ${properties} ${name}";
+    in
+      lib.concatMapStringsSep "\n" cmd sorted;
+
+  mountDatasets =
+    let
+      datasetlist = lib.mapAttrsToList lib.nameValuePair datasets;
+      mounts = lib.filter ({ value, ... }: hasDefinedMount value) datasetlist;
+      sorted = lib.sort (left: right: (lib.stringLength left.value.mount) < (lib.stringLength right.value.mount)) mounts;
+      cmd = { name, value }:
+        ''
+          mkdir -p /mnt${lib.escapeShellArg value.mount}
+          mount -t zfs ${name} /mnt${lib.escapeShellArg value.mount}
+        '';
+    in
+      lib.concatMapStringsSep "\n" cmd sorted;
+
+  unmountDatasets =
+    let
+      datasetlist = lib.mapAttrsToList lib.nameValuePair datasets;
+      mounts = lib.filter ({ value, ... }: hasDefinedMount value) datasetlist;
+      sorted = lib.sort (left: right: (lib.stringLength left.value.mount) > (lib.stringLength right.value.mount)) mounts;
+      cmd = { name, value }:
+        ''
+          umount /mnt${lib.escapeShellArg value.mount}
+        '';
+    in
+      lib.concatMapStringsSep "\n" cmd sorted;
+
+
+  fileSystemsCfgFile =
+    let
+      mountable = lib.filterAttrs (_: value: hasDefinedMount value) datasets;
+    in
+      pkgs.runCommand "filesystem-config.nix" {
+        buildInputs = with pkgs; [ jq nixpkgs-fmt ];
+        filesystems = builtins.toJSON {
+          fileSystems = lib.mapAttrs'
+            (
+              dataset: attrs:
+                {
+                  name = attrs.mount;
+                  value = {
+                    fsType = "zfs";
+                    device = "${dataset}";
+                  };
+                }
+            )
+            mountable;
+        };
+        passAsFile = [ "filesystems" ];
+      } ''
+      (
+        echo "builtins.fromJSON '''"
+        jq . < "$filesystemsPath"
+        echo "'''"
+      ) > $out
+
+      nixpkgs-fmt $out
+    '';
+
+  mergedConfig =
+    if configFile == null
+    then fileSystemsCfgFile
+    else
+      pkgs.runCommand "configuration.nix" {
+        buildInputs = with pkgs; [ nixpkgs-fmt ];
+      }
+        ''
+          (
+            echo '{ imports = ['
+            printf "(%s)\n" "$(cat ${fileSystemsCfgFile})";
+            printf "(%s)\n" "$(cat ${configFile})";
+            echo ']; }'
+          ) > $out
+
+          nixpkgs-fmt $out
+        '';
+
+  image = (
+    pkgs.vmTools.override {
+      rootModules =
+        [ "zfs" "9p" "9pnet_virtio" "virtio_pci" "virtio_blk" ] ++
+          (pkgs.lib.optional (pkgs.stdenv.isi686 || pkgs.stdenv.isx86_64) "rtc_cmos");
+      kernel = modulesTree;
+    }
+  ).runInLinuxVM (
+    pkgs.runCommand name
+      {
+        QEMU_OPTS = "-drive file=$bootDiskImage,if=virtio,cache=unsafe,werror=report"
+         + " -drive file=$rootDiskImage,if=virtio,cache=unsafe,werror=report";
+        preVM = ''
+          PATH=$PATH:${pkgs.qemu_kvm}/bin
+          mkdir $out
+          bootDiskImage=boot.raw
+          qemu-img create -f raw $bootDiskImage ${toString bootSize}M
+
+          rootDiskImage=root.raw
+          qemu-img create -f raw $rootDiskImage ${toString rootSize}M
+        '';
+
+        postVM = ''
+          ${if formatOpt == "raw" then ''
+          mv $bootDiskImage $out/${bootFilename}
+          mv $rootDiskImage $out/${rootFilename}
+        '' else ''
+          ${pkgs.qemu}/bin/qemu-img convert -f raw -O ${formatOpt} ${compress} $bootDiskImage $out/${bootFilename}
+          ${pkgs.qemu}/bin/qemu-img convert -f raw -O ${formatOpt} ${compress} $rootDiskImage $out/${rootFilename}
+        ''}
+          bootDiskImage=$out/${bootFilename}
+          rootDiskImage=$out/${rootFilename}
+          set -x
+          ${postVM}
+        '';
+      } ''
+      export PATH=${tools}:$PATH
+      set -x
+
+      cp -sv /dev/vda /dev/sda
+      cp -sv /dev/vda /dev/xvda
+
+      parted --script /dev/vda -- \
+        mklabel gpt \
+        mkpart no-fs 1MiB 2MiB \
+        set 1 bios_grub on \
+        align-check optimal 1 \
+        mkpart ESP fat32 2MiB -1MiB \
+        align-check optimal 2 \
+        print
+
+      sfdisk --dump /dev/vda
+
+
+      zpool create \
+        ${stringifyProperties "  -o" rootPoolProperties} \
+        ${stringifyProperties "  -O" rootPoolFilesystemProperties} \
+        ${rootPoolName} /dev/vdb
+      parted --script /dev/vdb -- print
+
+      ${createDatasets}
+      ${mountDatasets}
+
+      mkdir -p /mnt/boot
+      mkfs.vfat -n ESP /dev/vda2
+      mount /dev/vda2 /mnt/boot
+
+      mount
+
+      # Install a configuration.nix
+      mkdir -p /mnt/etc/nixos
+      # `cat` so it is mutable on the fs
+      cat ${mergedConfig} > /mnt/etc/nixos/configuration.nix
+
+      export NIX_STATE_DIR=$TMPDIR/state
+      nix-store --load-db < ${closureInfo}/registration
+
+      nixos-install \
+        --root /mnt \
+        --no-root-passwd \
+        --system ${config.system.build.toplevel} \
+        --substituters "" \
+        ${lib.optionalString includeChannel ''--channel ${channelSources}''}
+
+      df -h
+
+      umount /mnt/boot
+      ${unmountDatasets}
+
+      zpool export ${rootPoolName}
+    ''
+  );
+in
+image

nixos/maintainers/scripts/ec2/amazon-image-zfs.nix

@@ -0,0 +1,12 @@
+{
+  imports = [ ./amazon-image.nix ];
+  ec2.zfs = {
+    enable = true;
+    datasets = {
+      "tank/system/root".mount = "/";
+      "tank/system/var".mount = "/var";
+      "tank/local/nix".mount = "/nix";
+      "tank/user/home".mount = "/home";
+    };
+  };
+}

nixos/maintainers/scripts/ec2/amazon-image.nix

@@ -4,6 +4,7 @@ with lib;
 
 let
   cfg = config.amazonImage;
+
 in {
 
   imports = [ ../../../modules/virtualisation/amazon-image.nix ];
@@ -53,15 +54,7 @@ in {
     };
   };
 
-  config.system.build.amazonImage = import ../../../lib/make-disk-image.nix {
-    inherit lib config;
-    inherit (cfg) contents format name;
-    pkgs = import ../../../.. { inherit (pkgs) system; }; # ensure we use the regular qemu-kvm package
-    partitionTableType = if config.ec2.efi then "efi"
-                         else if config.ec2.hvm then "legacy+gpt"
-                         else "none";
-    diskSize = cfg.sizeMB;
-    fsType = "ext4";
+  config.system.build.amazonImage = let
     configFile = pkgs.writeText "configuration.nix"
       ''
         { modulesPath, ... }: {
@@ -72,24 +65,96 @@ in {
           ${optionalString config.ec2.efi ''
             ec2.efi = true;
           ''}
+          ${optionalString config.ec2.zfs.enable ''
+            ec2.zfs.enable = true;
+            networking.hostId = "${config.networking.hostId}";
+          ''}
         }
       '';
-    postVM = ''
-      extension=''${diskImage##*.}
-      friendlyName=$out/${cfg.name}.$extension
-      mv "$diskImage" "$friendlyName"
-      diskImage=$friendlyName
 
-      mkdir -p $out/nix-support
-      echo "file ${cfg.format} $diskImage" >> $out/nix-support/hydra-build-products
+    zfsBuilder = import ../../../lib/make-zfs-image.nix {
+      inherit lib config configFile;
+      inherit (cfg) contents format name;
+      pkgs = import ../../../.. { inherit (pkgs) system; }; # ensure we use the regular qemu-kvm package
 
-      ${pkgs.jq}/bin/jq -n \
-        --arg label ${lib.escapeShellArg config.system.nixos.label} \
-        --arg system ${lib.escapeShellArg pkgs.stdenv.hostPlatform.system} \
-        --arg logical_bytes "$(${pkgs.qemu}/bin/qemu-img info --output json "$diskImage" | ${pkgs.jq}/bin/jq '."virtual-size"')" \
-        --arg file "$diskImage" \
-        '$ARGS.named' \
-        > $out/nix-support/image-info.json
-    '';
-  };
+      includeChannel = true;
+
+      bootSize = 1000; # 1G is the minimum EBS volume
+
+      rootSize = cfg.sizeMB;
+      rootPoolProperties = {
+        ashift = 12;
+        autoexpand = "on";
+      };
+
+      datasets = config.ec2.zfs.datasets;
+
+      postVM = ''
+        extension=''${rootDiskImage##*.}
+        friendlyName=$out/${cfg.name}
+        rootDisk="$friendlyName.root.$extension"
+        bootDisk="$friendlyName.boot.$extension"
+        mv "$rootDiskImage" "$rootDisk"
+        mv "$bootDiskImage" "$bootDisk"
+
+        mkdir -p $out/nix-support
+        echo "file ${cfg.format} $bootDisk" >> $out/nix-support/hydra-build-products
+        echo "file ${cfg.format} $rootDisk" >> $out/nix-support/hydra-build-products
+
+       ${pkgs.jq}/bin/jq -n \
+         --arg system_label ${lib.escapeShellArg config.system.nixos.label} \
+         --arg system ${lib.escapeShellArg pkgs.stdenv.hostPlatform.system} \
+         --arg root_logical_bytes "$(${pkgs.qemu}/bin/qemu-img info --output json "$bootDisk" | ${pkgs.jq}/bin/jq '."virtual-size"')" \
+         --arg boot_logical_bytes "$(${pkgs.qemu}/bin/qemu-img info --output json "$rootDisk" | ${pkgs.jq}/bin/jq '."virtual-size"')" \
+         --arg root "$rootDisk" \
+         --arg boot "$bootDisk" \
+        '{}
+          | .label = $system_label
+          | .system = $system
+          | .disks.boot.logical_bytes = $boot_logical_bytes
+          | .disks.boot.file = $boot
+          | .disks.root.logical_bytes = $root_logical_bytes
+          | .disks.root.file = $root
+          ' > $out/nix-support/image-info.json
+      '';
+    };
+
+    extBuilder = import ../../../lib/make-disk-image.nix {
+      inherit lib config configFile;
+
+      inherit (cfg) contents format name;
+      pkgs = import ../../../.. { inherit (pkgs) system; }; # ensure we use the regular qemu-kvm package
+
+      fsType = "ext4";
+      partitionTableType = if config.ec2.efi then "efi"
+                           else if config.ec2.hvm then "legacy+gpt"
+                           else "none";
+
+      diskSize = cfg.sizeMB;
+
+      postVM = ''
+        extension=''${diskImage##*.}
+        friendlyName=$out/${cfg.name}.$extension
+        mv "$diskImage" "$friendlyName"
+        diskImage=$friendlyName
+
+        mkdir -p $out/nix-support
+        echo "file ${cfg.format} $diskImage" >> $out/nix-support/hydra-build-products
+
+       ${pkgs.jq}/bin/jq -n \
+         --arg system_label ${lib.escapeShellArg config.system.nixos.label} \
+         --arg system ${lib.escapeShellArg pkgs.stdenv.hostPlatform.system} \
+         --arg logical_bytes "$(${pkgs.qemu}/bin/qemu-img info --output json "$diskImage" | ${pkgs.jq}/bin/jq '."virtual-size"')" \
+         --arg file "$diskImage" \
+          '{}
+          | .label = $system_label
+          | .system = $system
+          | .logical_bytes = $logical_bytes
+          | .file = $file
+          | .disks.root.logical_bytes = $logical_bytes
+          | .disks.root.file = $file
+          ' > $out/nix-support/image-info.json
+      '';
+    };
+  in if config.ec2.zfs.enable then zfsBuilder else extBuilder;
 }

nixos/modules/virtualisation/amazon-image.nix

@@ -41,17 +41,23 @@ in
 
     boot.growPartition = cfg.hvm;
 
-    fileSystems."/" = {
+    fileSystems."/" = mkIf (!cfg.zfs.enable) {
       device = "/dev/disk/by-label/nixos";
       fsType = "ext4";
       autoResize = true;
     };
 
-    fileSystems."/boot" = mkIf cfg.efi {
+    fileSystems."/boot" = mkIf (cfg.efi || cfg.zfs.enable) {
+      # The ZFS image uses a partition labeled ESP whether or not we're
+      # booting with EFI.
       device = "/dev/disk/by-label/ESP";
       fsType = "vfat";
     };
 
+    services.zfs.expandOnBoot = mkIf cfg.zfs.enable "all";
+
+    boot.zfs.devNodes = mkIf cfg.zfs.enable "/dev/";
+
     boot.extraModulePackages = [
       config.boot.kernelPackages.ena
     ];

nixos/modules/virtualisation/amazon-options.nix

@@ -1,7 +1,46 @@
 { config, lib, pkgs, ... }:
-{
+let
+  inherit (lib) types;
+in {
   options = {
     ec2 = {
+      zfs = {
+        enable = lib.mkOption {
+          default = false;
+          internal = true;
+          description = ''
+            Whether the EC2 instance uses a ZFS root.
+          '';
+        };
+
+        datasets = lib.mkOption {
+          description = ''
+            Datasets to create under the `tank` and `boot` zpools.
+
+            **NOTE:** This option is used only at image creation time, and
+            does not attempt to declaratively create or manage datasets
+            on an existing system.
+          '';
+
+          default = {};
+
+          type = types.attrsOf (types.submodule {
+            options = {
+              mount = lib.mkOption {
+                description = "Where to mount this dataset.";
+                type = types.nullOr types.string;
+                default = null;
+              };
+
+              properties = lib.mkOption {
+                description = "Properties to set on this dataset.";
+                type = types.attrsOf types.string;
+                default = {};
+              };
+            };
+          });
+        };
+      };
       hvm = lib.mkOption {
         default = lib.versionAtLeast config.system.stateVersion "17.03";
         internal = true;
@@ -18,4 +57,17 @@
       };
     };
   };
+
+  config = lib.mkIf config.ec2.zfs.enable {
+    networking.hostId = lib.mkDefault "00000000";
+
+    fileSystems = let
+      mountable = lib.filterAttrs (_: value: ((value.mount or null) != null)) config.ec2.zfs.datasets;
+    in lib.mapAttrs'
+      (dataset: opts: lib.nameValuePair opts.mount {
+        device = dataset;
+        fsType = "zfs";
+      })
+      mountable;
+  };
 }

nixos/release.nix

@@ -217,6 +217,20 @@ in rec {
     }).config.system.build.amazonImage)
 
   );
+  amazonImageZfs = forMatchingSystems [ "x86_64-linux" "aarch64-linux" ] (system:
+
+    with import ./.. { inherit system; };
+
+    hydraJob ((import lib/eval-config.nix {
+      inherit system;
+      modules =
+        [ configuration
+          versionModule
+          ./maintainers/scripts/ec2/amazon-image-zfs.nix
+        ];
+    }).config.system.build.amazonImage)
+
+  );
 
 
   # Test job for https://github.com/NixOS/nixpkgs/issues/121354 to test