diff --git a/host_vars/hobbes.n39.eu/vars.yml b/host_vars/hobbes.n39.eu/vars.yml
index ad3650e..39f5c6f 100644
--- a/host_vars/hobbes.n39.eu/vars.yml
+++ b/host_vars/hobbes.n39.eu/vars.yml
@@ -1,3 +1,4 @@
+---
 server_admin: "admin+hobbes@netz39.de"
 mac: "b8:27:eb:f9:43:43"
 kiosk_user: pi
diff --git a/host_vars/krypton.n39.eu/vars.yml b/host_vars/krypton.n39.eu/vars.yml
index 51abc0c..9fbed9c 100644
--- a/host_vars/krypton.n39.eu/vars.yml
+++ b/host_vars/krypton.n39.eu/vars.yml
@@ -1,2 +1,3 @@
+---
 server_admin: "admin+krypton@netz39.de"
 ldap_admin_password: "{{ vault_ldap_admin_password }}"
diff --git a/host_vars/localhost/vars.yml b/host_vars/localhost/vars.yml
index cd3c13d..fd4d599 100644
--- a/host_vars/localhost/vars.yml
+++ b/host_vars/localhost/vars.yml
@@ -1,3 +1,4 @@
+---
 grafana_users:
   - name: Netz39
     email: accounts+grafana@netz39.de
diff --git a/host_vars/platon.n39.eu/vars.yml b/host_vars/platon.n39.eu/vars.yml
index 2f04ab2..294efed 100644
--- a/host_vars/platon.n39.eu/vars.yml
+++ b/host_vars/platon.n39.eu/vars.yml
@@ -1,3 +1,4 @@
+---
 server_admin: "admin+platon@netz39.de"
 mac: "b8:27:eb:8f:98:2f"
 gatekeeper_user: pi
diff --git a/host_vars/pottwal.n39.eu/vars.yml b/host_vars/pottwal.n39.eu/vars.yml
index e01460f..c70ce80 100644
--- a/host_vars/pottwal.n39.eu/vars.yml
+++ b/host_vars/pottwal.n39.eu/vars.yml
@@ -1,3 +1,4 @@
+---
 server_admin: "admin+pottwal@netz39.de"
 ansible_python_interpreter: /usr/bin/python3
 data_dir: "/srv/data"
diff --git a/host_vars/radon.n39.eu/vars.yml b/host_vars/radon.n39.eu/vars.yml
index db62d9e..fc9bff6 100644
--- a/host_vars/radon.n39.eu/vars.yml
+++ b/host_vars/radon.n39.eu/vars.yml
@@ -1,3 +1,4 @@
+---
 server_admin: "admin+radon@netz39.de"
 pwr_meter_amqp_user: "pwr-meter"
 pwr_meter_amqp_pass: "{{ vault_pwr_meter_amqp_pass }}"
diff --git a/host_vars/tau.netz39.de/vars.yml b/host_vars/tau.netz39.de/vars.yml
index ac0c976..7fb2b4d 100644
--- a/host_vars/tau.netz39.de/vars.yml
+++ b/host_vars/tau.netz39.de/vars.yml
@@ -1,2 +1,3 @@
+---
 server_admin: "admin+tau@netz39.de"
 mysql_root_pw: "{{ vault_mysql_root_pw }}"
diff --git a/host_vars/unicorn.n39.eu/vars.yml b/host_vars/unicorn.n39.eu/vars.yml
index 0855361..9a7141f 100644
--- a/host_vars/unicorn.n39.eu/vars.yml
+++ b/host_vars/unicorn.n39.eu/vars.yml
@@ -1 +1,2 @@
+---
 server_admin: "admin+unicorn@netz39.de"