ansible-role-elasticsearch/tasks/checkParameters.yml

# Check for mandatory parameters

- fail: msg="es_instance_name must be specified and cannot be blank"
  when: es_instance_name is not defined or es_instance_name == ''

- set_fact: multi_cast={{ (es_version | version_compare('2.0', '<') and es_config['discovery.zen.ping.multicast.enabled'] is not defined) or (es_config['discovery.zen.ping.multicast.enabled'] is defined and es_config['discovery.zen.ping.multicast.enabled'])}}

- debug: msg="WARNING - It is recommended you specify the parameter 'http.port' when multicast is disabled"
  when: not multi_cast and es_config['http.port'] is not defined

- debug: msg="WARNING - It is recommended you specify the parameter 'transport.tcp.port' when multicast is disabled"
  when: not multi_cast and es_config['transport.tcp.port'] is not defined

- debug: msg="WARNING - It is recommended you specify the parameter 'discovery.zen.ping.unicast.hosts' when multicast is disabled"
  when: not multi_cast and es_config['discovery.zen.ping.unicast.hosts'] is not defined

#If the user attempts to lock memory they must specify a heap size
- fail: msg="If locking memory with bootstrap.mlockall a heap size must be specified"
  when: es_config['bootstrap.mlockall'] is defined and es_config['bootstrap.mlockall'] == True and es_heap_size is not defined