diff --git a/docs/operators/handbook.md b/docs/operators/handbook.md
index 3776360..554b7e3 100644
--- a/docs/operators/handbook.md
+++ b/docs/operators/handbook.md
@@ -232,6 +232,12 @@ The requirements are:
 1. Swarm mode initialised
 1. Proxy network created
 
+!!! warning "You may need to log in/out"
+
+    When running `usermod ...`, you may need to (depending on your system) log
+    in and out again of your shell session to get the required permissions for
+    Docker.
+
 ```
 # docker install convenience script
 wget -O- https://get.docker.com | bash
diff --git a/docs/operators/tutorial.md b/docs/operators/tutorial.md
index 15fc912..dea0ce2 100644
--- a/docs/operators/tutorial.md
+++ b/docs/operators/tutorial.md
@@ -32,6 +32,12 @@ You need to keep port `:80` and `:443` free on your server for web proxying to y
 
 `abra` has support for creating servers (`abra server new`) but that is a more advanced automation feature which is covered in the [handbook](/operators/handbook). For this tutorial, we'll focus on the basics. Assuming you've managed to create a testing VPS with some `$hosting_provider`, you'll need to install Docker, add your user to the Docker group & setup swarm mode:
 
+!!! warning "You may need to log in/out"
+
+    When running `usermod ...`, you may need to (depending on your system) log
+    in and out again of your shell session to get the required permissions for
+    Docker.
+
 ```
 # docker install convenience script
 wget -O- https://get.docker.com | bash