package installation fails

[chatziparaskewas]

Executing this role as part of a playbook against a CentOS 7.4 Atomic Host fails upon installation of the chrony package.

include_role:
  name: influxdata.chrony
vars:
  chrony_server: some.server.com prefer iburst

TASK [influxdata.chrony : Install Chrony] ***********************************************************************************
fatal: [some.server.com]: FAILED! => {"changed": false, "msg": "missing required arguments: image, backend"}