Add squashfs output image format

The squashfs format brings a couple of advantages over the other
formats. Image is often an order of magnitude smaller and it can
be used natively, either as an initrd, either with loop mount.

Change-Id: If72940b0c4dafb2504c52dd0429a8eb3f8305751

bin/disk-image-create

@@ -102,7 +102,7 @@ function show_options () {
     echo "Options:"
     echo "    -a i386|amd64|armhf -- set the architecture of the image(default amd64)"
     echo "    -o imagename -- set the imagename of the output image file(default image)"
-    echo "    -t qcow2,tar,tgz,vhd,docker,aci,raw -- set the image types of the output image files (default qcow2)"
+    echo "    -t qcow2,tar,tgz,squashfs,vhd,docker,aci,raw -- set the image types of the output image files (default qcow2)"
     echo "       File types should be comma separated. VHD outputting requires the vhd-util"
     echo "       executable be in your PATH. ACI outputting requires the ACI_MANIFEST "
     echo "       environment variable be a path to a manifest file."
@@ -268,6 +268,12 @@ for X in ${!IMAGE_TYPES[@]}; do
                 exit 1
             fi
             ;;
+        squashfs)
+            if [ -z "$(which mksquashfs)" ]; then
+                echo "squashfs output format specified but no mksquashfs executable found."
+                exit 1
+            fi
+            ;;
         docker)
             if [ -z "$(which docker)" ]; then
                 echo "docker output format specified but no docker executable found."
@@ -452,6 +458,10 @@ for X in ${!IMAGE_TYPES[@]} ; do
     fi
     sudo chown $USER: $IMAGE_NAME.${IMAGE_TYPES[$X]}
     unset IMAGE_TYPES[$X]
+  elif [ "${IMAGE_TYPES[$x]}" == "squashfs" ]; then
+    sudo mksquashfs ${TMP_BUILD_DIR}/mnt $IMAGE_NAME.squash -comp xz \
+                    -noappend -root-becomes ${TMP_BUILD_DIR}/mnt \
+                    -wildcards -e "proc/*" -e "sys/*" -no-recovery
   elif [ "${IMAGE_TYPES[$X]}" == "docker" ]; then
     sudo tar -C ${TMP_BUILD_DIR}/mnt -cf - --exclude ./sys \
              --exclude ./proc --xattrs --xattrs-include=\* . \
@@ -476,7 +486,7 @@ if [[ (! $IMAGE_ELEMENT =~ no-final-image) && "$IS_RAMDISK" == "0" ]]; then
     # We have to do raw last because it is destructive
     if [ "$IMAGE_TYPE" = "raw" ]; then
       has_raw_type=1
-    else
+    elif [ "$IMAGE_TYPE" != "squashfs" ]; then
       compress_and_save_image $IMAGE_NAME.$IMAGE_TYPE
     fi
   done

bindep.txt

@@ -1,2 +1,3 @@
 # This is a cross-platform list tracking distribution packages needed by tests;
 # see http://docs.openstack.org/infra/bindep/ for additional information.
+squashfs-tools

doc/source/user_guide/building_an_image.rst

@@ -52,6 +52,7 @@ formats are:
  * qcow2
  * tar
  * tgz
+ * squashfs
  * vhd
  * docker
  * raw

releasenotes/notes/squashfs-output-91c1f0dc37474d3c.yaml

@@ -0,0 +1,3 @@
+---
+features:
+  - New squashfs image output format.

tests/run_output_format_test.sh

@@ -59,8 +59,8 @@ function build_test_image() {
     fi
 }
 
-test_formats="tar tgz raw qcow2 docker aci"
+test_formats="tar tgz squashfs raw qcow2 docker aci"
-for binary in qemu-img docker ; do
+for binary in qemu-img docker mksquashfs; do
     if [ -z "$(which $binary)" ]; then
         echo "Warning: No $binary binary found, cowardly refusing to run tests."
         exit 1