HaProxy (cannot bind socket, select test failed)

Question

Hello everyone, Im working about an high availbility project, I had to put in production an haproxy for some applications. Everything was ok after some basics tests but I had some errors and cant fix it. Does someone have some ideas ?

here is the test

# /usr/sbin/haproxy -d -f /etc/haproxy/haproxy.cfg

Available polling systems : 

 sepoll : pref=400,  test result OK 
 epoll : pref=300,  test result OK 
 poll : pref=200,  test result OK 
 select : pref=150,  test result FAILED 

Total: 4 (3 usable), will use sepoll. 
Using sepoll() as the polling mechanism. 
[ALERT] 174/160258 (22038) : Starting proxy mysql: cannot bind socket 
[ALERT] 174/160258 (22038) : Starting proxy http: cannot bind socket 

There is my file haproxy.cfg

global 
log 127.0.0.1 local0 notice
user haproxy
group haproxy
maxconn 32000
ulimit-n 65536

defaults
log global
option dontlognull
retries 2
timeout connect 3000
timeout server 5000
timeout client 5000
option redispatch

listen  mysql
bind *:3306
mode tcp
option tcplog
balance roundrobin
option  mysql-check user haproxy_check
server mysql1 10.83.83.167:3306 check
server mysql2 10.83.83.168:3306 check
server mysql3 10.83.83.169:3306 check 

listen  http
mode http
bind *:80
stats enable
stats uri /stats
stats auth admin:HaProxy2014
acl app1_cluster_acl hdr_beg(host) -i app1
acl app2_cluster_acl hdr_beg(host) -i app2
acl mysql_cluster_acl hdr_beg(host) -i mysql
use_backend app1_cluster if app1_cluster_acl
use_backend app2_cluster if app2_cluster_acl
use_backend mysql_cluster if mysql_cluster_acl 

backend app1_cluster
mode http
cookie SERVERID insert indirect nocache
option  forwardfor header X-Real-IP
option  http-server-close
option  httplog
balance roundrobin
server serv1 10.83.83.203:80 check cookie serv1
server serv2 10.83.83.204:80 check cookie serv2 

backend app2_cluster
mode http
cookie SERVERID insert indirect nocache
option  forwardfor header X-Real-IP
option  http-server-close
option  httplog
balance roundrobin
server serv1 10.83.83.187:80 check cookie serv1
server serv2 10.83.83.188:80 check cookie serv2 

backend mysql_cluster
mode http
cookie SERVERID insert indirect nocache
option  forwardfor header X-Real-IP
option  http-server-close
option  httplog
balance roundrobin
server mysql1 10.83.83.167:80 check cookie serv1
server mysql2 10.83.83.168:80 check cookie serv2
server mysql3 10.83.83.169:80 check cookie serv2

Solution

I get the same error if there is already a mysql or http service running on my load balancer in addition to ruuning on the back ends.

For example if nginx/apache is already running on my load balancer.

$ netstat -anp | grep ":80"
tcp        0      0 127.0.0.1:80            0.0.0.0:*               LISTEN      3646/nginx    

And i try to start my load balancer with bind *:80 i get a similar error.

$ haproxy -d -f /etc/haproxy/haproxy.cfg
Available polling systems :
      epoll : pref=300,  test result OK
      poll : pref=200,  test result OK
     select : pref=150,  test result FAILED
Total: 3 (2 usable), will use epoll.
Using epoll() as the polling mechanism.
[ALERT] 195/001456 (1903) : Starting frontend www: cannot bind socket [0.0.0.0:80]

If you need to have a mysql or http instance listening on 127.0.0.1 then you can specify the ip of another interface in the bind call.

bind: 10.0.0.20:80

With the latest version of haproxy you can now even use variables.

bind ${LB1}:80

And export these from the haproxy startup script or /etc/default/haproxy

export LB1="10.0.0.20"

Otherwise perhaps there is an issue with your haproxy startup scripts.