HAProxy + Percona XtraDB Cluster

Posted by rottmanj on Server Fault See other posts from Server Fault or by rottmanj
Published on 2013-01-11T06:57:16Z Indexed on 2014/06/02 9:31 UTC
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I am attempting to setup HAproxy in conjunction with Percona XtraDB Cluster on a series of 3 EC2 instances. I have found a few tutorials online dealing with this specific issue, but I am a bit stuck.

Both the Percona servers and the HAproxy servers are running ubuntu 12.04. The HAProxy version is 1.4.18,

When I start HAProxy I get the following error: Server pxc-back/db01 is DOWN, reason: Socket error, check duration: 2ms.

I am not really sure what the issue could be. I have verified the following:

  1. EC2 security groups ports are open
  2. Poured over my config files looking for issues. I currently do not see any.
  3. Ensured that xinetd was installed
  4. Ensured that I am using the correct ip address of the mysql server.

Any help with this is greatly appreciated.

Here are my current config

Load Balancer

/etc/haproxy/haproxy.cfg

global
  log 127.0.0.1 local0
  log 127.0.0.1 local1 notice
  maxconn 4096
  user haproxy
  group haproxy
  debug
  #quiet
  daemon

defaults
  log global
  mode http
  option tcplog
  option dontlognull
  retries 3
  option redispatch
  maxconn 2000
  contimeout 5000
  clitimeout 50000
  srvtimeout 50000

frontend pxc-front
  bind 0.0.0.0:3307
  mode tcp
  default_backend pxc-back

frontend stats-front
  bind 0.0.0.0:22002
  mode http
  default_backend stats-back

backend pxc-back
  mode tcp
  balance leastconn
  option httpchk
  server db01 10.86.154.105:3306 check port 9200 inter 12000 rise 3 fall 3

backend stats-back 
  mode http
  balance roundrobin
  stats uri /haproxy/stats

MySql Server

/etc/xinetd.d/mysqlchk

# default: on
# description: mysqlchk
service mysqlchk
{
# this is a config for xinetd, place it in /etc/xinetd.d/
        disable = no
        flags           = REUSE
        socket_type     = stream
        port            = 9200
        wait            = no
        user            = nobody
        server          = /usr/bin/clustercheck
        log_on_failure  += USERID
        #only_from       = 0.0.0.0/0
        # recommended to put the IPs that need
        # to connect exclusively (security purposes)
        per_source      = UNLIMITED
}

MySql Server

/etc/services

Added the line mysqlchk 9200/tcp # mysqlchk

MySql Server

/usr/bin/clustercheck

# GNU nano 2.2.6 File: /usr/bin/clustercheck
#!/bin/bash
#
# Script to make a proxy (ie HAProxy) capable of monitoring Percona XtraDB Cluster nodes properly
#
# Author: Olaf van Zandwijk <[email protected]>
# Documentation and download: https://github.com/olafz/percona-clustercheck
#
# Based on the original script from Unai Rodriguez
#

MYSQL_USERNAME="testuser"
MYSQL_PASSWORD=""
ERR_FILE="/dev/null"
AVAILABLE_WHEN_DONOR=0

#
# Perform the query to check the wsrep_local_state
#
WSREP_STATUS=`mysql --user=${MYSQL_USERNAME} --password=${MYSQL_PASSWORD} -e "SHOW STATUS LIKE 'wsrep_local_state';" 2>${ERR_FILE} | awk '{if (NR!=1){print $2}}' 2>${ERR_FILE}`

if [[ "${WSREP_STATUS}" == "4" ]] || [[ "${WSREP_STATUS}" == "2" && ${AVAILABLE_WHEN_DONOR} == 1 ]]
then
    # Percona XtraDB Cluster node local state is 'Synced' => return HTTP 200
    /bin/echo -en "HTTP/1.1 200 OK\r\n"
    /bin/echo -en "Content-Type: text/plain\r\n"
    /bin/echo -en "\r\n"
    /bin/echo -en "Percona XtraDB Cluster Node is synced.\r\n"
    /bin/echo -en "\r\n"
else
    # Percona XtraDB Cluster node local state is not 'Synced' => return HTTP 503
    /bin/echo -en "HTTP/1.1 503 Service Unavailable\r\n"
    /bin/echo -en "Content-Type: text/plain\r\n"
    /bin/echo -en "\r\n"
    /bin/echo -en "Percona XtraDB Cluster Node is not synced.\r\n"
    /bin/echo -en "\r\n"
fi

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