title: haproxy cookie can't roundrobin?
body: <p>I want do like this,look my haproxy:</p>
  
  <pre><code>backend app
  balance     roundrobin
  cookie  ha_gray_cookie insert indirect nocache
  server  app1 127.0.0.1:5001 cookie 110 check
  server  app2 127.0.0.1:5002 cookie 110 check
  server  app3 127.0.0.1:5003 cookie 110 check
  server  app4 127.0.0.1:5004 cookie 120 check
  server  app5 127.0.0.1:5005 cookie 120 check
  server  app6 127.0.0.1:5006 cookie 120 check
  server  app7 127.0.0.1:5007 cookie 120 check
  server  app8 127.0.0.1:5008 cookie 120 check
  server  app9 127.0.0.1:5009 cookie 120 check
  </code></pre>
  
  <p>when users come to here,this has 3/9 chance to visit the new versions(5001 5002 5003) and 6/9 chance to visit the old versions.</p>
  
  <p>above config has some problems, namely that when I set cookie to 110, and then client always visits app1, when I set cookie to 120 then client always visits app4.</p>
  
  <p>I want do this: If I set cookie to 110, client can visit all 3 servers (5001,5002,5003) by roundrobin</p>