Why is HaProxy returning a 503 Service Unavailable error?

N

Nikolay Baranenko2019-09-19 11:52:38

HAproxy

Nikolay Baranenko, 2019-09-19 11:52:38

Hello.
There is a host with HAProxy
that accepts incoming http/https traffic
192.168.1.12
and distributes it to 2 backends
10.0.1.12
10.0.1.13
using HAProxy version 1.8
config

---------------------------------------------------------------------
# Global settings
#---------------------------------------------------------------------
global
    # to have these messages end up in /var/opt/rh/rh-haproxy18/log/haproxy.log you will
    # need to:
    #
    # 1) configure syslog to accept network log events.  This is done
    #    by adding the '-r' option to the SYSLOGD_OPTIONS in
    #    /etc/sysconfig/syslog
    #
    # 2) configure local2 events to go to the /var/opt/rh/rh-haproxy18/log/haproxy.log
    #   file. A line like the following can be added to
    #   /etc/sysconfig/syslog
    #
    #    local2.*                       /var/opt/rh/rh-haproxy18/log/haproxy.log
    #
    log         127.0.0.1 local2

    chroot	/var/opt/rh/rh-haproxy18/lib/haproxy
    pidfile     /var/run/rh-haproxy18-haproxy.pid
    maxconn     20000
    daemon

    #nbproc 1
    #nbthread 3
    #cpu-map auto:1/1-3 0-2

    # turn on stats unix socket
    stats socket /var/opt/rh/rh-haproxy18/lib/haproxy/stats

#---------------------------------------------------------------------
# common defaults that all the 'listen' and 'backend' sections will
# use if not designated in their block
#---------------------------------------------------------------------
defaults
    mode                    http
    log                     global
    option                  httplog
    option                  dontlognull
    option http-server-close
    option forwardfor       except 127.0.0.0/8
    option                  redispatch
    retries                 3
    timeout http-request    10s
    timeout queue           1m
    timeout connect         10s
    timeout client          15s
    timeout server          15s
    timeout http-keep-alive 5s
    timeout check           3s
    maxconn                 20001

#---------------------------------------------------------------------
# main frontend which proxys to the backends
#---------------------------------------------------------------------
frontend http_frontend
    bind *:80
    default_backend http_backend

backend http_backend
    mode http
    server server1 10.0.1.12:8081 check
    server server1 10.0.1.13:8081 check

Service is up and running

# systemctl restart rh-haproxy18-haproxy.service && systemctl status rh-haproxy18-haproxy.service

● rh-haproxy18-haproxy.service - HAProxy Load Balancer
   Loaded: loaded (/usr/lib/systemd/system/rh-haproxy18-haproxy.service; enabled; vendor preset: disabled)
   Active: active (running) since Wed 2019-09-18 19:43:14 MSK; 15h ago
  Process: 53539 ExecStartPre=/opt/rh/rh-haproxy18/root/usr/sbin/haproxy -f $CONFIG -c -q (code=exited, status=0/SUCCESS)
 Main PID: 53541 (haproxy)
   CGroup: /system.slice/rh-haproxy18-haproxy.service
           ├─53541 /opt/rh/rh-haproxy18/root/usr/sbin/haproxy -Ws -f /etc/opt/rh/rh-haproxy18/haproxy/haproxy.cfg -p /run/rh-haproxy18-haproxy.pid
           └─53543 /opt/rh/rh-haproxy18/root/usr/sbin/haproxy -Ws -f /etc/opt/rh/rh-haproxy18/haproxy/haproxy.cfg -p /run/rh-haproxy18-haproxy.pid

# ps aux | grep haproxy

root      53541  0.0  0.0  77636  3632 ?        Ss   Sep18   0:00 /opt/rh/rh-haproxy18/root/usr/sbin/haproxy -Ws -f /etc/opt/rh/rh-haproxy18/haproxy/haproxy.cfg -p /run/rh-haproxy18-haproxy.pid
root      53543  0.0  0.0  80776  3736 ?        Ss   Sep18   0:00 /opt/rh/rh-haproxy18/root/usr/sbin/haproxy -Ws -f /etc/opt/rh/rh-haproxy18/haproxy/haproxy.cfg -p /run/rh-haproxy18-haproxy.pid

#netstat -tulpn | grep 80

tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      54542/haproxy

checking status
# curl http://localhost

<html><body><h1>503 Service Unavailable</h1>
No server is available to handle this request.
</body></html>

despite the fact that
# curl -iv 10.0.1.12:8081
it
# curl -iv 10.0.1.13:8081
works out
What could be the problem?