Add virtualbox-iso target

Lots of other, small quality of life improvements to build process
Output of build serial console to artifacts upon failure
Reducing verbosity of Packer, now that serial output is captured
Fixed sizing problems with the boot partitions of Ubuntu versions
Use of Mac builders for Virtualbox targets
Updating Ubuntu builders to 22.04, as well

.github/workflows/build.yml

@@ -25,12 +25,15 @@ jobs:
 
   build:
     name: Build box
-    runs-on: ubuntu-22.04
+    runs-on: ${{ matrix.builder == 'virtualbox-iso.x86_64' && 'macOS-12' || 'ubuntu-22.04' }}
     needs:
       - collect
     strategy:
       fail-fast: false
       matrix:
+        builder:
+          - virtualbox-iso.x86_64
+          - qemu.x86_64
         distro: ${{ fromJson( needs.collect.outputs.distros ) }}
         needs_timeout:
           - distros/ubuntu-20.04-x86_64.pkrvars.hcl
@@ -39,28 +42,35 @@ jobs:
         uses: actions/checkout@v3
         with:
           submodules: recursive
-      - uses: ./.github/actions/setup
+      - name: Setup system dependnecies
+        uses: ./.github/actions/setup
         with:
           ansible: true
-      - uses: ./.github/actions/install_packer
-      - uses: greg-hellings/make-space@main
-      - name: modify build timeouts, if necessary
+      - name: Install Packer and related tools
+        uses: ./.github/actions/install_packer
+      - name: Clear disk space
+        uses: greg-hellings/make-space@main
+      - name: Modify build timeouts, if necessary
         if: contains(matrix.needs_timeout, matrix.distro)
         shell: bash
         run: ./modify_timeout.sh "${{ matrix.distro }}"
       - name: Run generator, if necessary
         if: endsWith(matrix.distro, '.sh')
         run: "${{ matrix.distro }}"
-      - name: try build
+      - name: Build
         shell: bash
         run: |
           set -e
           # Strip .sh if it is a dynamic one
           file="$(printf "${{ matrix.distro }}" | sed -E -e 's/^(.*).sh$/\1/')"
           # Add a retry in case something bogus like a network failure happens
-          until packer build -var-file="${file}" -var "qemu_accelerator=tcg" ${{ github.event_name != 'release' && '-except=upload' || '' }} sources; do
-            sleep 1
-          done
+          packer build -only="${{ matrix.builder }}" -var-file="${file}" -var "qemu_accelerator=tcg" ${{ github.event_name != 'release' && '-except=upload' || '' }} sources
         env:
           VAGRANT_CLOUD_TOKEN: ${{ secrets.VAGRANT_CLOUD_TOKEN }}
-          PACKER_LOG: ${{ contains(matrix.needs_timeout, matrix.distro) && '1' || '1' }}
+          PACKER_LOG: ${{ contains(matrix.needs_timeout, matrix.distro) && '0' || '0' }}
+      - name: Upload artifact
+        if: ${{ failure() }}
+        uses: actions/upload-artifact@v3
+        with:
+          name: serial-output
+          path: serial-output*