diff --git a/roles/common/molecule/default/group_vars/parameters-optional.yml b/roles/common/molecule/default/group_vars/parameters-optional.yml
new file mode 100644
index 0000000000000000000000000000000000000000..23aa5cd33714bdcb21712593ef6ee85264e28502
--- /dev/null
+++ b/roles/common/molecule/default/group_vars/parameters-optional.yml
@@ -0,0 +1,61 @@
+---
+
+enable_backup: true
+apt_proxy: "http://10.31.127.2:3142/"
+os_users:
+  - name: user1
+  - name: user2
+    uid: 2001
+    additional_groups:
+      - group1
+      - group2
+    authorized_keys:
+      - "{{ lookup('file', 'tests/data/ssh/clientkey1.pub') }}"
+      - "{{ lookup('file', 'tests/data/ssh/clientkey2.pub') }}"
+    # Password is 'user2'.
+    password: "$6$wdXOQiMe09ugh0$VRIph2XA2QQyEYlAlH7zT4TPACDUalf/4FKpqG9JRHfKxANTcTug2ANCt450htcs0LikJfHLWofLP54jraFU61"
+  - name: user3
+    uid: 2002
+    additional_groups:
+      - group3
+    authorized_keys:
+      - "{{ lookup('file', 'tests/data/ssh/clientkey3.pub') }}"
+    # Password is 'user3'.
+    password: "$6$nmx.21uLqT$9LrUqNUgUwIM.l0KFKgr2.kDEwe2lo7IbBIhnG70AGW7GTFdWBUFnGAxH15YxikTXhDJD/uxd.NNgojEOjRvx1"
+os_groups:
+  - name: group1
+  - name: group2
+    gid: 3001
+  - name: group3
+    gid: 3002
+common_packages:
+  - units
+  - gnutls-bin
+  - "{{ 'libmariadb-client-lgpl-dev-compat' if ansible_distribution_release == 'jessie'
+  else 'libmariadbclient-dev-compat' if ansible_distribution_release == 'stretch' }}"
+  - emacs24-nox
+ca_certificates:
+  cacert1: "{{ lookup('file', 'tests/data/x509/ca1.cert.pem') }}"
+  cacert2: "{{ lookup('file', 'tests/data/x509/ca2.cert.pem') }}"
+extra_backup_patterns:
+  - /home/user1
+  - /home/user2
+incoming_connection_limit: 5/second
+incoming_connection_limit_burst: 5
+pipreqcheck_uid: 2500
+pipreqcheck_gid: 2500
+prompt_colour: cyan
+prompt_id: test
+# Purposefully set this to 3 servers to make sure we are
+# overriding the default configuration.
+ntp_servers:
+  - "0.debian.pool.ntp.org"
+  - "1.debian.pool.ntp.org"
+  - "2.debian.pool.ntp.org"
+# From backup_client role meta dependency.
+backup_encryption_key: "{{ lookup('file', 'tests/data/gnupg/backup_encryption_key') }}"
+backup_server: backup-server
+backup_server_host_ssh_public_keys:
+  - bougs-backup-server-key-1
+  - bougs-backup-server-key-2
+backup_ssh_key: "bogus-backup-client-key"