diff --git a/Makefile b/Makefile
index 758d9a93e25440e9ef60e0d4aded7629a1deb7b9..6419417f1f21ec4cf68ecf789368fdf663449eab 100644
--- a/Makefile
+++ b/Makefile
@@ -54,7 +54,9 @@ $(eval $(call mkabspath,GLUON_TARGETSDIR))
 $(eval $(call mkabspath,GLUON_PATCHESDIR))
 
 GLUON_VERSION := $(shell scripts/getversion.sh '.')
-GLUON_SITE_VERSION := $(shell scripts/getversion.sh '$(GLUON_SITEDIR)')
+
+# Set default SITE_VERSION if not set by user
+GLUON_SITE_VERSION ?= $(shell scripts/getversion.sh '$(GLUON_SITEDIR)')
 
 GLUON_MULTIDOMAIN ?= 0
 GLUON_AUTOREMOVE ?= 0
diff --git a/docs/user/getting_started.rst b/docs/user/getting_started.rst
index f8652d3177333e6f3912b161cfb29a03922c3680..5c8a0f770e8f8aeed343d828fde9b9ffc1e03a95 100644
--- a/docs/user/getting_started.rst
+++ b/docs/user/getting_started.rst
@@ -237,6 +237,11 @@ GLUON_RELEASE
   is available. The same GLUON_RELEASE has to be passed to ``make`` and ``make manifest``
   to generate a correct manifest.
 
+GLUON_SITE_VERSION
+  Version of the site configuration. This string is displayed in the config mode
+  and `gluon-info`. If unset, Gluon generates a version string using `git describe`
+  on the site folder.
+
 GLUON_TARGET
   Target architecture to build.