diff --git a/metal/hosts.yml b/metal/hosts.yml
index e20cd0bf..e848d2a4 100644
--- a/metal/hosts.yml
+++ b/metal/hosts.yml
@@ -4,10 +4,10 @@ controller:
 
 metal:
   hosts:
-    metal0: {ansible_host: 192.168.1.110, mac: 00-23-24-d1-f4-d6}
-    metal1: {ansible_host: 192.168.1.111, mac: 00-23-24-e7-04-60}
-    metal2: {ansible_host: 192.168.1.112, mac: 00-23-24-d1-f5-69}
-    metal3: {ansible_host: 192.168.1.113, mac: 00-23-24-d1-f3-f0}
+    metal0: {ansible_host: 192.168.1.110, mac: '00:23:24:d1:f4:d6'}
+    metal1: {ansible_host: 192.168.1.111, mac: '00:23:24:e7:04:60'}
+    metal2: {ansible_host: 192.168.1.112, mac: '00:23:24:d1:f5:69'}
+    metal3: {ansible_host: 192.168.1.113, mac: '00:23:24:d1:f3:f0'}
   vars:
     ansible_user: root
     ansible_ssh_private_key_file: ~/.ssh/id_ed25519