diff --git a/extraconfig/tasks/ssh/known_hosts_config.yaml b/extraconfig/tasks/ssh/known_hosts_config.yaml
index 9f027f4a30..ff09e3f359 100644
--- a/extraconfig/tasks/ssh/known_hosts_config.yaml
+++ b/extraconfig/tasks/ssh/known_hosts_config.yaml
@@ -11,7 +11,7 @@ resources:
     type: OS::Heat::SoftwareConfig
     properties:
       group: script
-      config: |
+      config:
         str_replace:
           params:
             KNOWN_HOSTS: {get_param: known_hosts}