For users running Elasticsearch 7.5.2, use the latest configure_elasticsearch_with_swarm_search.py script on each node instead of directly installing the 7.17.9 RPM. This script updates /etc/sysconfig/elasticsearch to use the default bundled JDK from Elasticsearch.
The configure script currently requires node.name to be set in /etc/elasticsearch/elasticsearch.yml. This is not the case with an SCI-installed Swarm Cluster Installer (SCI) deployed VM; uncomment the setting and set it to the default value of ${HOSTNAME}.