generate ssh key pair

Change-Id: I9f7cbdb0ba9379eed262cc211a5eff2be5b05f8a
diff --git a/roles/compute-node/meta/main.yml b/roles/compute-node/meta/main.yml
index 047a60f..2e50ead 100644
--- a/roles/compute-node/meta/main.yml
+++ b/roles/compute-node/meta/main.yml
@@ -12,5 +12,6 @@
   galaxy_tags:
     - cord
 dependencies:
+  - { role: prep }
   - { role: local-ubuntu-repository, when: ubuntu_apt_repo is defined }
   - { role : docker }