Enable external elasticsearch server

Add this lines to nuxeo.conf. 

#elasticsearch nodes addresses
elasticsearch.addressList=localhost:9300
# Remote elasticsearch cluster name to join.
elasticsearch.clusterName=elasticsearch
# Name of the Elasticsearch index for the default document repository
elasticsearch.indexName=nuxeo
# Number of replicas (not for embedded mode)
elasticsearch.indexNumberOfReplicas=1

Change localhost to address(es) of the elasicsearch servers.

Enable  elasticsearch for casebrowser search tab

add pi_query_search to the list of overrided pageproviders:

elasticsearch.override.pageproviders=default_search,pi_query_search