Add IMAGE_DEBUG variable

if this is set, then snf-image will run in debug mode.

snf-image-host/common.sh.in

@@ -372,6 +372,7 @@ fi
 
 : ${VARIANTS_DIR:="@sysconfdir@/ganeti/snf-image/variants"}
 : ${IMAGE_DIR:="@localstatedir@/lib/snf-image"}
+: ${IMAGE_DEBUG:="no"}
 : ${HELPER_DIR:="@HELPER_DIR@"}
 : ${HELPER_IMG:="@HELPER_IMG@"}
 : ${HELPER_KERNEL:="@HELPER_KERNEL@"}

snf-image-host/create

@@ -24,6 +24,13 @@ set -o pipefail
 
 ganeti_os_main
 
+if [ "$IMAGE_DEBUG" = "yes" ]; then
+    PS4='$(date "+%s.%N ($LINENO) + ")'
+    set -x
+elif [ "$IMAGE_DEBUG" != "no" ]; then
+    echo "Warning: Unsupported IMAGE_DEBUG value: \`$IMAGE_DEBUG'"
+fi
+
 # Save stderr to a file
 stderr=$(mktemp)
 add_cleanup rm "$stderr"

snf-image-host/defaults

@@ -10,7 +10,7 @@
 # IMAGE_DIR="/var/lib/snf-image"
 
 # IMAGE_DEBUG: turn on debugging output for the scripts
-# IMAGE_DEBUG=0
+# IMAGE_DEBUG=no
 
 # HELPER_DIR: Directory hosting the helper files
 # HELPER_DIR="/var/lib/snf-image/helper/"