How to Retain Proxy URL for all request using Apache load balancer

Question

I am trying to serve the requests to my Site through Proxy machine using Load balancer. When i try to access the Site by hitting http://PROXYSERVER.com, the HomePage comes up fine retaining the address bar URL with http://PROXYSERVER.com.

Now, when i try to access internal links for example, http://PROXYSERVER.com/services/ then the address bar URLchanges to the APPSERVER URL http://APPSERVER01.com/services/

NOTE: The Page comes up fine but the address bar URL is getting changed.

Expected behaviour is when user requests http://PROXYSERVER.com/services/ then the address bar should retain the proxy URL while serving the request

Here is my code for load balancing,

ProxyRequests off
 ServerName PROXYSERVER.com

# WebHead1
                BalancerMember http://APPSERVER01:80/ route=node1
                                # WebHead2
               BalancerMember http://APPSERVER02:80/ route=node2
                Order Deny,Allow
                Deny from none
                Allow from all
                ProxySet lbmethod=byrequests
               #ProxySet lbmethod=bybusyness
                ProxySet stickysession=BALANCEID

SetHandler balancer-manager
                Order deny,allow
                Allow from all
        
        # Point of Balance
        ProxyPass /balancer-manager !
        ProxyPass / balancer://mycluster/

Any suggestions will be appreciated.

HBruijn · Answer

The configuration you posted and the symptoms you describe point to a missing ProxyPassReverse directive.

Without it any URL's in the Location, Content-Location and URI headers on HTTP redirect responses send by either one of you application servers won't be modified. That exposes the real name/URL of the application server and the visitor will be directed to that URL rather instead of that of the proxy-server.

You would see such headers for instance when you go to a directory http://example.com/dirname and omit the trailing slash /.
In that case the active application server will send a HTTP 301 "moved permanently" header and append the trailing slash.

A trace with curl -v proxyserver.com/services will show something along the lines of:

> GET /services HTTP/1.1
> Host: proxyserver.com
> User-Agent: curl/7.43.0
> Accept: */*
>
< HTTP/1.1 301 Moved Permanently
< Date: Wed, 06 Jan 2016 09:27:31 GMT
< Server: Apache/2.2.15 (CentOS)
< Location: https://appserver01:/services/
< Content-Length: 328
< Connection: close
< Content-Type: text/html; charset=iso-8859-1
<

You resolve that by adding the correct ProxyPassReverse directive which tells Apache to rewrite such headers with that of the proxy URI

    # Point of Balance
    ProxyPass /balancer-manager !
    ProxyPass / balancer://mycluster/
    ProxyPassReverse / balancer://mycluster/

Depending on the version of Apache you're running you might experience behaviour similar to this older bug and could try explicit ProxyPassReverse directives for each member of the balancer pool:

    ProxyPass /balancer-manager !
    ProxyPass / balancer://mycluster/
    ProxyPassReverse / balancer://mycluster/
    # Ensure that headers sent by application servers get corrected:
    ProxyPassReverse / http://APPSERVER01:80/
    ProxyPassReverse / http://APPSERVER02:80/

How to Retain Proxy URL for all request using Apache load balancer

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