After upgrading to Elasticsearch 6.1 I can not use variable substitution. In this case:
xpack:
security:
authc:
realms:
ssl:
certificate_authorities: [ "${ELASTICSEARCH_CONFIG_PATH}/certs/myca.crt" ]
I am receiving exception which contain following text:
java.nio.file.NoSuchFileException: /app/volumes/config/${ELASTICSEARCH_CONFIG_PATH}/certs/myca.crt
In 6.0.1 it was working well.