diff --git a/src/mad/sh/create_container_image.sh b/src/mad/sh/create_container_image.sh
index 1cedf291a2..cfdbaee25b 100755
--- a/src/mad/sh/create_container_image.sh
+++ b/src/mad/sh/create_container_image.sh
@@ -18,6 +18,16 @@
 
 set -e
 
+function is_mounted {
+    grep -qs "$1" /proc/mounts
+}
+
+function clean {
+    if is_mounted "${tmp_dir}/${id}"; then
+        umount "${tmp_dir}/${id}"
+    fi
+}
+
 #-------------------------------------------------------------------------------
 # Configuration attributes and parameters
 #-------------------------------------------------------------------------------
@@ -27,14 +37,14 @@ GROUP=oneadmin
 
 DRIVER_PATH=$(dirname $0)
 
-tmp_dir=$1
-id=$2
-extension=$3
-terminal=$4
+tmp_dir="$1"
+id="$2"
+extension="$3"
+terminal="$4"
 
 commands=$(cat /dev/stdin)
 
-case $extension in
+case "$extension" in
     "tar.xz")
         untar_options="xvJpf"
         ;;
@@ -47,21 +57,29 @@ esac
 # Mount container disk image and untar rootfs contents to it
 #-------------------------------------------------------------------------------
 
+trap clean EXIT
+
 # try first to mount with the fuse2fs command and if that fails fallback to the
 # regular mount
-if ! fuse2fs -o nosuid $tmp_dir/$id.raw $tmp_dir/$id >/dev/null 2>&1 ; then
-    mount -o nosuid $tmp_dir/$id.raw $tmp_dir/$id
+# NOTE: fuse2fs returns zero even when actual mount fails
+_fuse_failed=''
+if ! fuse2fs -o nosuid "${tmp_dir}/${id}.raw" "${tmp_dir}/${id}" >/dev/null 2>&1 ; then
+    _fuse_failed=yes
 fi
 
-chown $USER:$GROUP $tmp_dir/$id
-tar $untar_options $tmp_dir/$id.$extension -C $tmp_dir/$id > /dev/null 2>&1
+if [ "$_fuse_failed" = "yes" ] || ! is_mounted "${tmp_dir}/${id}" ; then
+    mount -o nosuid "${tmp_dir}/${id}.raw" "${tmp_dir}/${id}"
+fi
+
+chown $USER:$GROUP "${tmp_dir}/${id}"
+tar $untar_options "${tmp_dir}/${id}.${extension}" -C "${tmp_dir}/${id}" > /dev/null 2>&1
 
 sync
 
 #-------------------------------------------------------------------------------
 # Execute context script to install OpenNebula contextualization packages
 #-------------------------------------------------------------------------------
-cat << EOF | chroot $tmp_dir/$id $terminal
+cat << EOF | chroot "${tmp_dir}/${id}" $terminal
 $commands
 echo "#Generated by OpenNebula" > /etc/resolv.conf
 rm -f /etc/ssh/ssh_host_* > /dev/null 2>&1
@@ -69,4 +87,4 @@ usermod -p '*' root > /dev/null 2>&1
 EOF
 sync
 
-umount $tmp_dir/$id
+exit 0
diff --git a/src/mad/sh/create_docker_image.sh b/src/mad/sh/create_docker_image.sh
index 3a7f5addc9..178a9e57e3 100755
--- a/src/mad/sh/create_docker_image.sh
+++ b/src/mad/sh/create_docker_image.sh
@@ -19,9 +19,13 @@
 # exit when any command fails
 set -e
 
+function is_mounted {
+    grep -qs "$1" /proc/mounts
+}
+
 function clean {
-    if  grep -qs "$dockerdir/mnt" /proc/mounts; then
-        umount $dockerdir/mnt
+    if is_mounted "${dockerdir}/mnt"; then
+        umount "${dockerdir}/mnt"
     fi
 }
 
@@ -52,7 +56,7 @@ fi
 
 # Check dockerdir is different than / and the directory name is an uuid
 regex_uuid="^\{?[0-9]+-[0-9]+-[0-9]+-[0-9]+-[0-9]+\}?$"
-if [ ! -d $dockerdir ] || [[ ! $(basename $dockerdir) =~ $regex_uuid ]]; then
+if [ ! -d "$dockerdir" ] || [[ ! $(basename "$dockerdir") =~ $regex_uuid ]]; then
     exit -1
 fi
 
@@ -62,14 +66,19 @@ trap clean EXIT
 
 # try first to mount with the fuse2fs command and if that fails fallback to the
 # regular mount
-if ! fuse2fs -o noexec,nodev,nosuid $img_raw $dockerdir/mnt >/dev/null 2>&1 ; then
-    mount -o noexec,nodev,nosuid $img_raw $dockerdir/mnt
+# NOTE: fuse2fs returns zero even when actual mount fails
+_fuse_failed=''
+if ! fuse2fs -o noexec,nodev,nosuid "$img_raw" "${dockerdir}/mnt" >/dev/null 2>&1 ; then
+    _fuse_failed=yes
 fi
 
-chmod o+w $dockerdir/mnt
-tar xpf $tarball -C $dockerdir/mnt > /dev/null 2>&1
+if [ "$_fuse_failed" = "yes" ] || ! is_mounted "${dockerdir}/mnt" ; then
+    mount -o noexec,nodev,nosuid "$img_raw" "${dockerdir}/mnt"
+fi
+
+chmod o+w "${dockerdir}/mnt"
+tar xpf "$tarball" -C "${dockerdir}/mnt" > /dev/null 2>&1
 
 sync
 
 exit 0
-