diff --git a/roles/vault/defaults/main.yml b/roles/vault/defaults/main.yml
index f70d67f7d..540b91295 100644
--- a/roles/vault/defaults/main.yml
+++ b/roles/vault/defaults/main.yml
@@ -83,7 +83,7 @@ vault_ca_options:
     format: pem
     ttl: "{{ vault_max_lease_ttl }}"
     exclude_cn_from_sans: true
-    altnames:
+    alt_names:
       - "vault.{{ system_namespace }}.svc.{{ dns_domain }}"
       - "vault.{{ system_namespace }}.svc"
       - "vault.{{ system_namespace }}"