diff --git a/defaults/main.yml b/defaults/main.yml
index 2d852ca..3a856b1 100644
--- a/defaults/main.yml
+++ b/defaults/main.yml
@@ -279,3 +279,7 @@
 bootstrap_filename: bootstrap.sh
 
 enable_system_check: 'n'
+
+custom_property_files:
+- ~/.apigee/custom-properties.yml
+- ~/.apigee-secure/credentials.yml
diff --git a/tasks/main.yml b/tasks/main.yml
index a57f895..448b1eb 100644
--- a/tasks/main.yml
+++ b/tasks/main.yml
@@ -30,3 +30,8 @@
 - include_tasks: postgres.yml
 
 - include_tasks: devportal_postgres.yml
+
+- name: Load Custom Properties
+  include_vars: "{{ item }}"
+  with_items: "{{ custom_property_files }}"
+  when: custom_property_files is defined
diff --git a/tasks/private_address.yml b/tasks/private_address.yml
index f7f0bc5..bd0915f 100644
--- a/tasks/private_address.yml
+++ b/tasks/private_address.yml
@@ -1,4 +1,10 @@
 ---
+- name: Assert existence of private address
+  assert:
+    that:
+      - "hostvars[inventory_hostname][interface_name].ipv4.address"
+    msg: "Unable to retrieve private address"
+
 - name: Normalized name for private address
   cache:
     key: 'private_address'