diff --git a/prepare-vms/README.md b/prepare-vms/README.md
index 7c90e9e4..7de3534c 100644
--- a/prepare-vms/README.md
+++ b/prepare-vms/README.md
@@ -4,6 +4,7 @@
 
 - [Docker](https://docs.docker.com/engine/installation/)
 - [Docker Compose](https://docs.docker.com/compose/install/)
+- [Parallel SSH](https://code.google.com/archive/p/parallel-ssh/) (on a Mac: `brew install pssh`)
 
 ## General Workflow
 
diff --git a/prepare-vms/workshopctl b/prepare-vms/workshopctl
index ff0235fd..07102ed1 100755
--- a/prepare-vms/workshopctl
+++ b/prepare-vms/workshopctl
@@ -20,7 +20,7 @@ DEPENDENCIES="
     ssh
     curl
     jq
-    parallel-ssh
+    pssh
     wkhtmltopdf
     man
     "