diff --git a/doc/install-guide/source/environment-messaging-obs.rst b/doc/install-guide/source/environment-messaging-obs.rst
index 020bbc1afe..535a1ec2d0 100644
--- a/doc/install-guide/source/environment-messaging-obs.rst
+++ b/doc/install-guide/source/environment-messaging-obs.rst
@@ -49,3 +49,8 @@ Install and configure components
       # rabbitmqctl set_permissions openstack ".*" ".*" ".*"
 
       Setting permissions for user "openstack" in vhost "/" ...
+
+.. note::
+
+   Sometimes it's necessary to increase the file descriptor limit for RabbitMQ to
+   handle a large number of connections properly.
diff --git a/doc/install-guide/source/environment-messaging-rdo.rst b/doc/install-guide/source/environment-messaging-rdo.rst
index 413c128e09..46ee6219f4 100644
--- a/doc/install-guide/source/environment-messaging-rdo.rst
+++ b/doc/install-guide/source/environment-messaging-rdo.rst
@@ -49,3 +49,8 @@ Install and configure components
       # rabbitmqctl set_permissions openstack ".*" ".*" ".*"
 
       Setting permissions for user "openstack" in vhost "/" ...
+
+.. note::
+
+   Sometimes it's necessary to increase the file descriptor limit for RabbitMQ to
+   handle a large number of connections properly.
diff --git a/doc/install-guide/source/environment-messaging-ubuntu.rst b/doc/install-guide/source/environment-messaging-ubuntu.rst
index 4bcf6c7c82..2bfb2a2c56 100644
--- a/doc/install-guide/source/environment-messaging-ubuntu.rst
+++ b/doc/install-guide/source/environment-messaging-ubuntu.rst
@@ -41,3 +41,8 @@ Install and configure components
       # rabbitmqctl set_permissions openstack ".*" ".*" ".*"
 
       Setting permissions for user "openstack" in vhost "/" ...
+
+.. note::
+
+   Sometimes it's necessary to increase the file descriptor limit for RabbitMQ to
+   handle a large number of connections properly.