diff --git a/sdk_container/src/third_party/coreos-overlay/sys-kernel/coreos-modules/files/sort_config.sh b/sdk_container/src/third_party/coreos-overlay/sys-kernel/coreos-modules/files/sort_config.sh
new file mode 100755
index 0000000000..462097cee8
--- /dev/null
+++ b/sdk_container/src/third_party/coreos-overlay/sys-kernel/coreos-modules/files/sort_config.sh
@@ -0,0 +1,45 @@
+#!/bin/bash
+
+# This script sorts the config files. It can be called with several
+# config files too, so it will sort each file separately.
+
+set -euo pipefail
+
+c_locale_sort()
+{
+    LC_ALL=C sort "${@}"
+}
+
+for cfgfile in "${@}"
+do
+    mapfile -t lines <"${cfgfile}"
+    declare -A variables # a hash map
+    for line in "${lines[@]}"
+    do
+        var="${line%%=*}"
+        var="${var#\# }"
+        var="${var%% *}"
+        if [[ ${variables[${var}]+isset} ]]
+        then
+            echo "${cfgfile}: overriding ${var}"
+        else
+            variables[${var}]=1
+            declare -a "LINES_FOR_${var}"
+        fi
+        declare -n var_lines="LINES_FOR_${var}"
+        var_lines+=("${line}")
+        unset -n var_lines
+    done
+    mapfile -t sorted_variables < <(printf '%s\n' "${!variables[@]}" | c_locale_sort)
+    truncate --size=0 "${cfgfile}"
+    for var in "${sorted_variables[@]}"
+    do
+        declare -n var_lines="LINES_FOR_${var}"
+        printf '%s\n' "${var_lines[@]}" >>"${cfgfile}"
+        unset var_lines
+        unset -n var_lines
+    done
+    unset sorted_variables
+    unset lines
+    unset variables
+done