title: HAProxy balance b/w multiple backends is not working
body: <p>My haproxy configuration is as below:</p>
  <pre><code>defaults
    log global
    mode http
    timeout connect 5000ms
    timeout client 50000ms
    timeout server 50000ms
    timeout queue 50000ms
    timeout http-request 60000ms
    timeout http-keep-alive 5000ms
    max-keep-alive-queue 10
    option httplog
    option redispatch
    option forwardfor
    option http-server-close
  
  frontend front
    bind *:80
    acl use_bar nbsrv(foo) -m int lt 1
    use_backend bar if use_bar
    default_backend foo
  
  backend foo
    server foo1 10.0.0.1:80 check
  
  backend bar
    server bar1 10.0.1.1:80 check
    server bar2 10.0.1.2:80 check
  </code></pre>
  <p>My issue is if the <code>backend foo</code> is down then the first request to the proxy fails with 503 Service Unavailable.</p>
  <p>The subsequent calls work as they get proxied to the <code>backend bar</code>.</p>
  <p>In no situation, we will like the API call to fail.</p>