title: Sticky session for load balancing with multiple domains
body: <p>so here is the scenario, i have a couple of load balanced servers, with a bunch of domains pointing to the load balancer IP. The website shows a different skin depending on the domain it was accessed from (this works fine). To assure session with the load balancing i used sticky session, problem is from what i know (which is not much) i need to define the domain for the cookie, but we have multiple possible domains.. i define the cookie as following on each web server:</p>
  
  <pre><code>RewriteEngine On
  RewriteRule .* - [CO=BALANCEID:balancer.lb1:.domain1.com]
  </code></pre>
  
  <p>since we have multiple domains, i thought i could add a rewrite rule for each domain and apache would deal with that, something like this:</p>
  
  <pre><code>RewriteEngine On
  RewriteRule .* - [CO=BALANCEID:balancer.lb1:.domain1.com]
  RewriteRule .* - [CO=BALANCEID:balancer.lb1:.domain2.com]
  RewriteRule .* - [CO=BALANCEID:balancer.lb1:.domain3.com]
  RewriteRule .* - [CO=BALANCEID:balancer.lb1:.domain4.com]
  </code></pre>
  
  <p>but as you probably have figured out by now, the sticky session works fine only for domain1.com, the first on the list.</p>
  
  <p>Any idea how to tackle this?</p>
  
  <p>EDIT:</p>
  
  <p>I am now trying this approach:</p>
  
  <pre><code>RewriteEngine On
  RewriteCond %{HTTP_X_FORWARDED_HOST} ^(www\.)?domain1\.com/ [NC]
  RewriteRule .* - [CO=BALANCEID:balancer.lb2:.domain1.com] [L]
  RewriteCond %{HTTP_X_FORWARDED_HOST} ^(www\.)?domain2\.com/ [NC]
  RewriteRule .* - [CO=BALANCEID:balancer.lb2:.domain2.com] [L]
  RewriteCond %{HTTP_X_FORWARDED_HOST} ^(www\.)?domain3\.com/ [NC]
  RewriteRule .* - [CO=BALANCEID:balancer.lb2:.domain3.com] [L]
  </code></pre>
  
  <p>but its not working at all, are those rules wrongly written or
  that logic simply wont work?</p>
  
  <p>PS: i also tried with HTTP_HOST instead of HTTP_X_FORWARDED_HOST but it had the same result. </p>