Merge pull request #2444 from edx/feanil/configurable_heartbeat_timeout

Be able to configure the mongo replica set heartbeat timeout.

playbooks/roles/mongo_3_0/defaults/main.yml

@@ -85,3 +85,4 @@ MONGO_S3_BACKUP_AWS_ACCESS_KEY: !!null
 MONGO_S3_BACKUP_AWS_SECRET_KEY: !!null
 
 MONGO_LOG_SERVERSTATUS: true
+MONGO_HEARTBEAT_TIMEOUT_SECS: 10

playbooks/roles/mongo_3_0/templates/repset_init.js.j2

@@ -31,7 +31,8 @@ config = {_id: '{{ mongo_repl_set }}', members: [{% for host in mongo_cluster_me
 {_id: {{ loop.index }}, host: '{{ host }}'}
 {%- endif -%}
 {% endfor %}
-]};
+],
+settings: { heartbeatTimeoutSecs: {{ MONGO_HEARTBEAT_TIMEOUT_SECS }} }};
 rs.initiate(config)
 
 sleep(30000)