Convert libvirtd to use make-disk-image

This fixes #931 by reusing the image builder of <nixpkgs/nixos/lib/make-disk-image.nix>. This image builder produces nixos.qcow2 instead of disk.qcow2. This image is now "baseless", so it obsoletes "qemu-img rebase". We can also remove our special-case image builder libvirtd-image.nix as a whole.
teto · Oct 16, 2019 · bdfa512 · bdfa512
1 parent 8c278af
commit bdfa512
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Showing 3 changed files with 13 additions and 120 deletions.
diff --git a/nix/libvirtd-image.nix b/nix/libvirtd-image.nix
diff --git a/nix/libvirtd.nix b/nix/libvirtd.nix
@@ -3,33 +3,19 @@
 with lib;
 
 let
-  sz = toString config.deployment.libvirtd.baseImageSize;
-  base_image = import ./libvirtd-image.nix { size = sz; };
   the_key = builtins.getEnv "NIXOPS_LIBVIRTD_PUBKEY";
-  ssh_image = pkgs.vmTools.runInLinuxVM (
-    pkgs.runCommand "libvirtd-ssh-image"
-      { memSize = 768;
-        preVM =
-          ''
-            mkdir $out
-            diskImage=$out/image
-            ${pkgs.vmTools.qemu}/bin/qemu-img create -f qcow2 -b ${base_image}/disk.qcow2 $diskImage
-          '';
-        buildInputs = [ pkgs.utillinux ];
-        postVM =
-          ''
-            mv $diskImage $out/disk.qcow2
-          '';
-      }
-      ''
-        mkdir /mnt
-        mount /dev/vda1 /mnt
-
-        mkdir -p /mnt/etc/ssh/authorized_keys.d
-        echo '${the_key}' > /mnt/etc/ssh/authorized_keys.d/root
-        umount /mnt
-      ''
-  );
+  ssh_image = import <nixpkgs/nixos/lib/make-disk-image.nix> {
+    name = "libvirtd-ssh-image";
+    format = "qcow2";
+    diskSize = config.deployment.libvirtd.baseImageSize * 1024;
+    config = config;
+    contents = [{
+      source = (pkgs.writeText "authorized_keys.d-root" the_key);
+      target = "/etc/ssh/authorized_keys.d/root";
+    }];
+    lib = pkgs.lib;
+    inherit pkgs;
+  };
 in
 
 {

diff --git a/nixopsvirtd/backends/libvirtd.py b/nixopsvirtd/backends/libvirtd.py
@@ -192,11 +192,7 @@ def _prepare_storage_volume(self):
             capture_stdout=True, env=newEnv).rstrip()
 
         temp_disk_path = os.path.join(self.depl.tempdir, 'disk-{}.qcow2'.format(self.name))
-        shutil.copyfile(os.path.join(temp_image_path, 'disk.qcow2'), temp_disk_path)
-        # Rebase onto empty backing file to prevent breaking the disk image
-        # when the backing file gets garbage collected.
-        self._logged_exec(["qemu-img", "rebase", "-f", "qcow2", "-b",
-                           "", temp_disk_path])
+        shutil.copyfile(os.path.join(temp_image_path, 'nixos.qcow2'), temp_disk_path)
 
         self.logger.log("uploading disk image...")
         image_info = self._get_image_info(temp_disk_path)