Apache config to load balance across a cluster of elasticsearch instances on 2 different servers, "es-cluster-1", and "es-cluster-2".

gistfile1.txt

<VirtualHost *:80>
    ServerName balancer.local
    Header add Set-Cookie "ROUTEID=.%{BALANCER_WORKER_ROUTE}e; path=/" env=BALANCER_ROUTE_CHANGED
    <Location /balancer-manager>
        ProxyPass !
        SetHandler balancer-manager
        #Require host example.com
        Require host localhost
    </Location>

    <Proxy balancer://elasticsearch/*>
        BalancerMember http://es-cluster-1:9200 route=1
        BalancerMember http://es-cluster-1:9201 route=2
        BalancerMember http://es-cluster-2:9200 route=3
        BalancerMember http://es-cluster-2:9201 route=3
        ProxySet stickysession=ROUTEID
    </Proxy>
    ProxyPass        / balancer://elasticsearch/
    ProxyPassReverse / balancer://elasticsearch/
</VirtualHost>