diff --git a/roles/xmpp_server/molecule/default/group_vars/parameters-optional.yml b/roles/xmpp_server/molecule/default/group_vars/parameters-optional.yml
index 5b6770eeadc3e9454db6dc1e358870020abd5d27..e22e5353dc8db1adba44bf7d3e05dc85358534f1 100644
--- a/roles/xmpp_server/molecule/default/group_vars/parameters-optional.yml
+++ b/roles/xmpp_server/molecule/default/group_vars/parameters-optional.yml
@@ -10,12 +10,8 @@ xmpp_ldap_base_dn: dc=local
 xmpp_ldap_password: prosodypassword
 xmpp_ldap_server: ldap-server
 xmpp_prosody_package: prosody-0.9
-xmpp_tls_certificate: "{{ lookup('file', 'tests/data/x509/parameters-optional_xmpp.cert.pem') }}"
-xmpp_tls_key: "{{ lookup('file', 'tests/data/x509/parameters-optional_xmpp.key.pem') }}"
-
-# Common parameters (general, not role).
-tls_certificate_dir: tests/data/x509/
-tls_private_key_dir: tests/data/x509/
+xmpp_tls_certificate: "{{ lookup('file', 'tests/data/x509/{{ inventory_hostname }}_xmpp.cert.pem') }}"
+xmpp_tls_key: "{{ lookup('file', 'tests/data/x509/{{ inventory_hostname }}_xmpp.key.pem') }}"
 
 # common
 ca_certificates: