I'm usung Ubuntu with haproxy 1.4.13 version.

Its load balancing two subdomains:

  • app1.domain.com
  • app2.domain.com

now i want to be able to use ACL to send based on url request to the right backends For example:

http://app1.domain.com/path/games/index.php  sould be send to backend1
http://app1.domain.com/path/photos/index.php should be send to backend2

http://app2.domain.com/path/mail/index.php  sould be send to backend3
http://app2.domain.com/path/wazap/index.php should be send to backend4

i did used the code the the following acl

frontend http-farm
        acl app1web     hdr_beg(host) -i app1  # for http://app1.domain.com
        acl app2web     hdr_beg(host) -i app2  # for http://app2.domain.com

acl msg-url-1 url_reg ^\/path/games/.*
acl msg-url-2 url_reg ^\/path/photos/.*
acl msg-url-3 url_reg ^\/path/mail/.*
acl msg-url-4 url_reg ^\/path/wazap/.*

use_backend games  if  msg-url-1 app1web
use_backend photos if  msg-url-2 app2web
use_backend mail if .....

backend games
        option httpchk GET /alive.php HTTP/1.1\r\nHost:\ app1.domain.com
        option  forwardfor
        balance roundrobin
        server  appsrv-1  check inter 2000 fall 3
        server  appsrv-2  check inter 2000 fall 3

backend photos
        option httpchk GET /alive.php HTTP/1.1\r\nHost:\ app2.domain.com
        option  forwardfor
        balance roundrobin
        server  appsrv-1  check inter 2000 fall 3
        server  appsrv-2  check inter 2000 fall 3


Since the path mail, photos...etc will be application pools on iis, i want to monitor them if they are alive, if the pool does not respond it should stop serving it.

my problem is for sure in the regular expression in the ACL acl msg-url-4 url_reg ^/path/wazap/.*

What should i change in the ACL to make it work ?

thanks for any hints

1 Answer 1


I don't know if it is an actual issue, but you don't need to escape slashes in HAProxy's regexes. Also, in your stated case, you don't even need regexes but can use simple string matchers. They are magnitudes faster than regexes. So your ACLs could look like this:

acl msg-url-3 url_beg /path/mail/
acl msg-url-4 url_beg /path/wazap/

If no server is available in a dispatched backend, HAProxy will return an HTTP 503 response. You can use errorloc or errorfile to customize the response.

But it could be that I slightly misunderstood your issue. It's not very clear what exactly is not working as expected.

  • Yes the url_beg did the job. If i want to say to backend to use if ACL is msg_url-3 AND appweb1 : use_backend if msg-url-3 appweb1 : use_backend if msg-url-3 & appweb1
    – Elgreco08
    Mar 31, 2011 at 8:02

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