add es_min_master_node setting

Signed-off-by: Jakub Sokołowski <jakub@status.im>

README.md

@@ -16,6 +16,7 @@ The only mandatory settings in [`defaults/main.yml`](defaults/main.yml) are:
 es_cluster_name: 'my-awesome-cluster'
 es_unicast_host: 'cluster-master.example.com'
 es_unicast_port: 9300
+es_master_min_nodes: 3
 ```
 
 The only other configuration that makes any difference are the JVM options like the ones related to heap size in:

defaults/main.yml

@@ -1,6 +1,10 @@
 ---
 # Mandatory variables
 es_cluster_name: ~
+# what hos to connect to in cluster
+es_unicast_host: ~
+es_unicast_port: 9300
+es_min_master_nodes: ~
 
 es_image: 'docker.elastic.co/elasticsearch/elasticsearch-oss:6.5.1'
 es_api_port: 9200
@@ -17,9 +21,6 @@ es_max_map_count: 262144
 es_jvm_min_heap: 2g
 es_jvm_max_heap: 2g
 
-es_unicast_host: ~
-es_unicast_port: 9300
-
 # WARNING: These links are legacy and might stop working at some point.
 geoip_url: 'http://geolite.maxmind.com/download/geoip/database'
 geoip_dbs:

templates/elasticsearch.yml.j2

@@ -5,7 +5,7 @@ network.bind_host: "{{ es_listen_addr }}"
 network.publish_host: "{{ ansible_local.tinc.vpn_ip }}"
 
 # minimum_master_nodes need to be explicitly set when bound on a public IP
-discovery.zen.ping.unicast.hosts: {{ es_master_nodes | to_json }}
-discovery.zen.minimum_master_nodes: {{ es_unicast_host }}:{{ es_unicast_port }}
+discovery.zen.ping.unicast.hosts: {{ es_unicast_host | mandatory }}:{{ es_unicast_port }}
+discovery.zen.minimum_master_nodes: {{ es_min_master_nodes | mandatory }}
 
-transport.profiles.default.port: {{ es_node_port }}
+transport.profiles.default.port: {{ es_node_port | mandatory }}