diff --git a/de/heat-templates/scripts/instance_boot.sh b/de/heat-templates/scripts/instance_boot.sh
index e3a8969..e160b24 100644
--- a/de/heat-templates/scripts/instance_boot.sh
+++ b/de/heat-templates/scripts/instance_boot.sh
@@ -521,6 +521,13 @@
     systemctl restart ntp
 }
 
+function wait_for_external_network {
+    function _check_access {
+        curl --connect-timeout 10 ${DOCKER_UCP_IMAGE%%/*} || (sleep 1; /bin/false)
+    }
+    retry 180 "Failed to wait for external networks reachable." _check_access
+}
+
 function prepare_network {
     if [ -z "${CONTROL_IP_ADDRESS}" ]; then
         wait_condition_send "FAILURE" "CONTROL_IP_ADDRESS is not found."
@@ -530,12 +537,6 @@
     systemctl restart systemd-resolved
     # Make sure local hostname is present in /etc/hosts
     sed -i "s/127.0.0.1 localhost/127.0.0.1 localhost\n${CONTROL_IP_ADDRESS} $(hostname -s).cluster.local $(hostname -s)/" /etc/hosts
-
-    function _check_access {
-        curl --connect-timeout 10 ${DOCKER_UCP_IMAGE%%/*} || (sleep 1; /bin/false)
-    }
-
-    retry 180 "Failed to wait for external networks reachable." _check_access
 }
 
 function workaround_default_forward_policy {
@@ -1000,6 +1001,7 @@
         # Please keep the "prepare_metadata_files", "disable-rp-filter", "network_config" and "prepare_network" functions
         # at the very beginning in the same order.
         ucp)
+            wait_for_external_network
             prepare_metadata_files
             disable_rp_filter
             network_config
@@ -1039,6 +1041,7 @@
             cron_disable_calico_offloading
             ;;
         master)
+            wait_for_external_network
             nested_virt_config
             prepare_metadata_files
             disable_rp_filter
@@ -1069,6 +1072,7 @@
             cron_disable_calico_offloading
             ;;
         worker)
+            wait_for_external_network
             if [[ "${CONFIGURE_HUGE_PAGES}" == true ]]; then
                 configure_huge_pages
             fi
@@ -1108,6 +1112,7 @@
             cron_disable_calico_offloading
             ;;
         spare)
+            wait_for_external_network
             prepare_metadata_files
             disable_rp_filter
             network_config
@@ -1131,6 +1136,7 @@
             cron_disable_calico_offloading
             ;;
         frr)
+            wait_for_external_network
             prepare_metadata_files
             disable_rp_filter
             network_config