diff --git a/roles/elastic-stack/ansible-elasticsearch/templates/elasticsearch.yml.j2 b/roles/elastic-stack/ansible-elasticsearch/templates/elasticsearch.yml.j2
index e8cefff1..6ca12c6f 100644
--- a/roles/elastic-stack/ansible-elasticsearch/templates/elasticsearch.yml.j2
+++ b/roles/elastic-stack/ansible-elasticsearch/templates/elasticsearch.yml.j2
@@ -16,7 +16,7 @@ cluster.initial_master_nodes:
   - {{ item }}
 {% endfor %}
 {% else %}
-node.master: "{{ elasticsearch_master_candidate }}"
+node.master: "{{ elasticsearch_master_candidate|lower }}"
 discovery.seed_hosts:
 {% for item in elasticsearch_discovery_nodes %}
   - {{ item }}