diff --git a/README.rst b/README.rst
index 0184a83..784873e 100644
--- a/README.rst
+++ b/README.rst
@@ -739,6 +739,26 @@
       libvirt:
         cpu_model: IvyBridge
 
+RNG (Random Number Generator) device path
+----------------------
+
+The path to an RNG (Random Number Generator) device that will be used
+as the source of entropy on the host.
+The recommended source of entropy is /dev/urandom.
+Permitted options are: /dev/random, /dev/urandom or /dev/hwrng.
+Default: /dev/urandom
+
+.. code-block:: yaml
+
+  nova:
+    controller:
+      libvirt:
+        rng_dev_path: /dev/random
+
+    compute:
+      libvirt:
+        rng_dev_path: /dev/random
+
 
 Nova compute workarounds
 ------------------------