diff --git a/etc/tempest.conf.sample b/etc/tempest.conf.sample
index 3147859..dc26e18 100644
--- a/etc/tempest.conf.sample
+++ b/etc/tempest.conf.sample
@@ -63,6 +63,10 @@
 flavor_ref = 1
 flavor_ref_alt = 2
 
+# User names used to authenticate to an instance for a given image.
+image_ssh_user = root
+image_alt_ssh_user = root
+
 # Number of seconds to wait while looping to check the status of an
 # instance that is building.
 build_interval = 10