Made Change to have Configurable option to enable/disable docker image

rules/config

@@ -107,3 +107,6 @@ ENABLE_MGMT_FRAMEWORK = y
 
 # ENABLE_RESTAPI - build docker-sonic-restapi for configuring the switch using REST APIs
 ENABLE_RESTAPI = n
+
+# ENABLE_NAT - build docker-sonic-nat for nat support
+ENABLE_NAT = y

rules/docker-nat.mk

@@ -13,13 +13,17 @@ $(DOCKER_NAT)_DBG_IMAGE_PACKAGES = $($(DOCKER_CONFIG_ENGINE_STRETCH)_DBG_IMAGE_P
 
 $(DOCKER_NAT)_LOAD_DOCKERS += $(DOCKER_CONFIG_ENGINE_STRETCH)
 
+ifeq ($(ENABLE_NAT), y)
 SONIC_DOCKER_IMAGES += $(DOCKER_NAT)
 SONIC_INSTALL_DOCKER_IMAGES += $(DOCKER_NAT)
 SONIC_STRETCH_DOCKERS += $(DOCKER_NAT)
+endif
 
+ifeq ($(ENABLE_NAT), y)
 SONIC_DOCKER_DBG_IMAGES += $(DOCKER_NAT_DBG)
 SONIC_INSTALL_DOCKER_DBG_IMAGES += $(DOCKER_NAT_DBG)
 SONIC_STRETCH_DBG_DOCKERS += $(DOCKER_NAT_DBG)
+endif
 
 $(DOCKER_NAT)_CONTAINER_NAME = nat
 $(DOCKER_NAT)_RUN_OPT += --privileged -t

slave.mk

@@ -116,6 +116,11 @@ ifeq ($(SONIC_ENABLE_SFLOW),y)
 ENABLE_SFLOW = y
 endif
 
+ifeq ($(SONIC_ENABLE_NAT),y)
+ENABLE_NAT = y
+endif
+
+
 include $(RULES_PATH)/functions
 include $(RULES_PATH)/*.mk
 ifneq ($(CONFIGURED_PLATFORM), undefined)
@@ -203,6 +208,7 @@ $(info "BUILD_TIMESTAMP"                 : "$(BUILD_TIMESTAMP)")
 $(info "BLDENV"                          : "$(BLDENV)")
 $(info "VS_PREPARE_MEM"                  : "$(VS_PREPARE_MEM)")
 $(info "ENABLE_SFLOW"                    : "$(ENABLE_SFLOW)")
+$(info "ENABLE_NAT"                      : "$(ENABLE_NAT)")
 $(info )
 
 ifeq ($(SONIC_USE_DOCKER_BUILDKIT),y)
@@ -650,6 +656,7 @@ $(addprefix $(TARGET_PATH)/, $(SONIC_INSTALLERS)) : $(TARGET_PATH)/% : \
 	export enable_system_telemetry="$(ENABLE_SYSTEM_TELEMETRY)"
 	export enable_restapi="$(ENABLE_RESTAPI)"
 	export enable_ztp="$(ENABLE_ZTP)"
+	export enable_nat="$(ENABLE_NAT)"
 	export shutdown_bgp_on_start="$(SHUTDOWN_BGP_ON_START)"
 	export enable_pfcwd_on_start="$(ENABLE_PFCWD_ON_START)"
 	export installer_debs="$(addprefix $(STRETCH_DEBS_PATH)/,$($*_INSTALLS))"