title: HAProxy for postgresql Load Balancer start error - cannot bind socket
body: <p>I am setting postgresql loadbalance using Haproxy and I met a error messages as below:</p>
  <p>Jun 30 07:57:43 vm0 systemd[1]: Starting HAProxy Load Balancer...
  Jun 30 07:57:43 vm0 haproxy[15084]: [ALERT] 180/075743 (15084) : Starting proxy ReadWrite: cannot bind socket [0.0.0.0:8081]
  Jun 30 07:57:43 vm0 haproxy[15084]: [ALERT] 180/075743 (15084) : Starting proxy ReadOnly: cannot bind socket [0.0.0.0:8082]
  Jun 30 07:57:43 vm0 systemd[1]: haproxy.service: Main process exited, code=exited, status=1/FAILURE
  Jun 30 07:57:43 vm0 systemd[1]: haproxy.service: Failed with result 'exit-code'.
  Jun 30 07:57:43 vm0 systemd[1]: Failed to start HAProxy Load Balancer.</p>
  <p>the below is my haproxy.cfg file and I kept checking all the possiblilites but I couldn't find the reason why I have the error. actualy I check the port is already used but no other process use the port 8001, 8002</p>
  <p>-- haproxy.cfg
  listen ReadWrite
  bind *:8081
  option httpchk
  http-check expect status 200
  default-server inter 3s fall 3 rise 2 on-marked-down shutdown-sessions
  server pg1 pg1:5432 maxconn 100 check port 23267</p>
  <p>listen ReadOnly
  bind *:8082
  option httpchk
  http-check expect status 206
  default-server inter 3s fall 3 rise 2 on-marked-down shutdown-sessions
  server pg2 pg1:5432 maxconn 100 check port 23267
  server pg3 pg2:5432 maxconn 100 check port 23267</p>