diff --git a/install/index.md b/install/index.md
index 2d7e9505b8..b4e2e0329b 100644
--- a/install/index.md
+++ b/install/index.md
@@ -32,7 +32,7 @@ infrastructure has all the [requirements DTR needs to run](system-requirements.m
 
 Since DTR requires a Docker Universal Control Plane (UCP) cluster
 to run, you need to install UCP first.
-[Learn how to install UCP](https://docs.docker.com/ucp/installation/install-production/).
+[Learn how to install UCP](https://docs.docker.com/ucp/installation/install-production/). Make sure that the node you install DTR on is already joined to the UCP cluster.
 
 
 ## Step 3. Install DTR
@@ -113,7 +113,7 @@ This step is optional.
 To set up DTR for [high availability](../high-availability/index.md),
 you can add more replicas to your DTR cluster. Adding more replicas allows you
 to load-balance requests across all replicas, and keep DTR working if a
-replica fails.
+replica fails. Each replica must be located on a node already joined to the UCP cluster.
 
 To add replicas to a DTR cluster, use the `docker/dtr join` command. To add
 replicas: