Adding packer host tooling

.gitea/workflows/gitea-main-ci.yaml

@@ -75,11 +75,17 @@ jobs:
         # libguestfs (virt-*), erofs-utils (mkfs.erofs), cryptsetup
         # (veritysetup), jq, systemd-ukify (ukify), buildah (OCI), plus qemu +
         # shellcheck for the lint gate.
+        #
+        # libguestfs builds a supermin appliance on first use, which needs a
+        # kernel + modules present on the runner (incl. xfs, to read the build
+        # VM's xfs root). The runner container ships none, so install one and
+        # make /boot readable (Ubuntu ships vmlinuz mode 0600).
         run: |
           sudo apt-get update
           sudo apt-get install -y --no-install-recommends \
-            qemu-system-x86 qemu-utils libguestfs-tools \
+            qemu-system-x86 qemu-utils libguestfs-tools linux-image-generic \
             erofs-utils cryptsetup-bin jq systemd-ukify buildah shellcheck
+          sudo chmod 0644 /boot/vmlinuz-* 2>/dev/null || true
 
       -
         name: Setup Packer
@@ -106,6 +112,14 @@ jobs:
         name: packer validate
         run: packer validate .
 
+      -
+        name: Verify libguestfs appliance (fast gate)
+        # Fail in ~1 min if supermin can't build/boot the appliance, instead of
+        # after the ~17-min VM build when extract-artifacts.sh first runs virt-ls.
+        env:
+          LIBGUESTFS_BACKEND: direct
+        run: libguestfs-test-tool
+
       -
         name: Registry login
         # Enables oci_push=true in the build step below.