Shameless ripoff from the ff3l site2domain package

site2domain/Makefile

@@ -0,0 +1,31 @@
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=site2domain
+PKG_VERSION:=1
+
+PKG_BUILD_DIR := $(BUILD_DIR)/$(PKG_NAME)
+
+include ../../../package/gluon.mk
+
+define Package/site2domain
+  SECTION:=gluon
+  CATEGORY:=Gluon
+  TITLE:=Set gluon.core.domain according to legacy site name, to prepare for multidomain gluon
+endef
+
+define Build/Prepare
+	mkdir -p $(PKG_BUILD_DIR)
+endef
+
+define Build/Configure
+endef
+
+define Build/Compile
+	$(call GluonSrcDiet,./luasrc,$(PKG_BUILD_DIR)/luadest/)
+endef
+
+define Package/site2domain/install
+	$(CP) $(PKG_BUILD_DIR)/luadest/* $(1)/
+endef
+
+$(eval $(call BuildPackage,site2domain))

site2domain/luasrc/lib/gluon/upgrade/590-site2domain

@@ -0,0 +1,22 @@
+#!/usr/bin/lua
+
+local site = require 'gluon.site_config'
+local fs = require 'nixio.fs'
+
+local sitecode = site.site_code
+
+if sitecode == 'ffhh-sued' then
+  domain = 'ffhh_sued'
+elseif sitecode == 'ffhh-west' then
+  domain = 'ffhh_west'
+elseif sitecode == 'ffhh-nowe' then
+  domain = 'ffhh_nowe'
+elseif sitecode == 'ffhh-ost' then
+  domain = 'ffhh_ost'
+else
+  domain = 'ffhh_nowe'
+end
+
+local content = 'config core \'core\'\n\toption domain \'' .. domain .. '\'\n'
+
+fs.writefile('/etc/config/gluon', content)