Compiling Latest Linux Kernel

Hi Friends,

As per requirement of our client, recently I compiled latest stable Linux kernel (linux-3.9.7) on my CentOS-6.3.
So as usual I wanna share steps for compiling the kernel :)

Below are the steps. Please follow if you also want to do the same.

Step 1) Download latest stable Linux Kernel from http://kernel.org/ and untar the package.

[root@localhost ~]# cd /usr/src/

[root@localhost src]# wget https://www.kernel.org/pub/linux/kernel/v3.x/linux-3.9.7.tar.xz

[root@localhost src]#tar -xvf linux-3.9.7.tar.xz

step 2) Choose appropriate Module 

[root@localhost src]# cd linux-3.9.7

[root@localhost linux-3.9.7 ]# make menuconfig

Note: This will show kernel configuration screen . Navigate and deselect things (drivers) you do not need. In case of doubt just leave the initial option/selection. Save the configuration and exit the menu. 

After saving your configuration (it is stored in the ".config" file) exit from screen.

Step 3) compile the kernel

[root@localhost linux-3.9.7 ]#make

Note: This is time consuming task and will take more then hr's depending on your hardware.  

Step 4) copy all the modules to a new directory, "/lib/modules/3.9.7"

[root@localhost linux-3.9.7 ]#make modules_install

Step 5) copy compiled files into appropriate locations

[root@localhost linux-3.9.7 ]#make install

Step 6) Remove all generated files + config + various backup files 

[root@localhost linux-3.9.7 ]#make mrproper

That's all about Kernel compiling. And Please don't forget to edit grub.conf to change default boot option with new kernel.

Enjoy !!!!!!!

SSH Port Forwarding

Hi Friends,

Let’s understand SSH Port forwarding concept with below examples.

I have two machine station-y (172.24.40.110) and station-z(172.24.40.120)

Example 1)

[root@station-z ~]# ssh -L 8080:yahoo.com:80 -N root@172.24.40.110

(I, SSH Client will listen for traffic on my host's port 8080 and send it to you, SSHD on 172.24.40.110. 

You will decrypt it and forward that traffic to port 80 on yahoo.com)

So after executing above command on station-z, when station-z tries to access http://localhost it will redirect to yahoo.com

Example 2)

[root@station-z ~]# ssh -R 8080:127.0.0.1:25 -N 172.24.40.110

(You the SSHD on 172.24.40.110 will listen for the traffic on your port 8080 and send it to me. I, ssh client will decrypt it and forward that traffic to port 25 on me as if it came from me.)

So after executing above command on station-z, when station-y tries to access their local port 8080 ([root@station-y ~]# telnet 0 8080)  it will redirect to port 25 of station-z 

Firewall Port Redirection through Iptables

Friends,

Recently I implemented firewall rule for incoming traffic on port 80 on firewall (10.10.0.100) will redirect to port 8080 of internal webserver(172.24.40.110).

Below is the command that I executed on my Linux based Firewall

[root@station-z ]#iptables -t nat -I PREROUTING-p tcp --dport 80 -d 10.10.0.100 -j DNAT --to 172.24.40.110:8080

IPTABLES NAT Rule Implementation

Friend,

Recently my network Admin has blocked Facebook access to all our Desktop-PC.

But fortunately I have access of one of Linux system where then haven’t implemented firewall rule.

So I MASQUERADE my outgoing traffic from my PC to that Linux System to get Facebook Access. J

It’s Very easy & if you want you could also test this on your Lab.

Example: - My PC (eth0: 172.24.40.110)

Linux PC [eth0: 172.24.40.120 (Lan Interface) eth1: 10.10.20.1 (Wan Interface)]

Step 1) On My PC (eth0: 172.24.40.110) set “Default Gatway to Linux machine(eth0: 172.24.40.120)

Step 2) On Linux machine set IP Forwarding

[root@station-y ]#vi /etc/sysctl.conf

net.ipv4.ip_forward = 1

Step 3) Apply NAT rule to MASQUERADE all traffic to eth1 (Wan Interface)

[root@station-y ]# iptables -t nat -I POSTROUTING -s 172.24.40.0/24 -o eth1 -j MASQUERADE

Installing Zabbix with postgresql in CentOS6

Friend , recently I configured Zabbix with postgresql in my office infrastructure.

We have one zabbix master server (192.168.0.1) and one pgsql database server (192.168.0.2)

Below are the step that I performs on configuring zabbix.

Step 1) Download and install RPM’s for postgresql in database server (192.168.0.2)

[root@localhost ~]#wget http://yum.postgresql.org/9.1/redhat/rhel-6-x86_64/pgdg-redhat91-9.1-5.noarch.rpm

[root@localhost ~]#rpm -ivh pgdg-redhat91-9.1-5.noarch.rpm

[root@localhost ~]#yum install postgresql91-server postgresql91-contrib

[root@localhost ~]#/etc/init.d/postgresql-9.1 restart

[root@localhost ~]#service postgresql-9.1 initdb

Step 2) Configure Postgresql on (192.168.0.2)

[root@localhost ~]# su – postgres

-bash-4.1$ psql

postgres=# CREATE DATABASE zabbix WITH ENCODING='UTF-8';

postgres=# CREATE USER zabbix WITH PASSWORD 'zabbix';

postgres=# GRANT ALL ON DATABASE zabbix TO zabbix;

postgres=# GRANT ALL PRIVILEGES ON DATABASE zabbix to postgres;

postgres=# ALTER USER Postgres WITH PASSWORD 'redhat';

postgres=# \q

-bash-4.1$

-bash-4.1$ logout

[root@localhost ~]#vi /var/lib/pgsql/9.1/data/pg_hba.conf

****************

# "local" is for Unix domain socket connections only

local   all             all                                     md5

# IPv4 local connections:

host    all             all             127.0.0.1/32            md5

host    all             all             10.10.2.0/16            md5

******************

[root@localhost ~]#vi /var/lib/pgsql/9.1/data/ postgresql.conf

**************

listen_addresses = '192.168.0.2'         # what IP address(es) to listen on;

                                        # comma-separated list of addresses;

                                        # defaults to 'localhost', '*' = all

                                        # (change requires restart)

port = 5432    

**************

[root@localhost ~]#/etc/init.d/postgresql-9.1 restart

Step 3) Configure php.ini in Zabbix server (192.168.0.1)

[root@localhost ~]#yum -y install gcc net-snmp-devel curl-devel gcc make curl-devel httpd php php-pgsql php-bcmath php-gd php-mbstring net-snmp-devel fping e2fsprogs-devel zlib-devel libgssapi-devel krb5-devel openssl-devel libidn-devel iksemel-devel libXpm openssh-clients  php-xmlrpc sharutils OpenIPMI-devel libssh2-devel php-xml

[root@localhost ~]#vi /etc/php.ini

*******

max_execution_time = 300

memory_limit = 128M

post_max_size = 16M

upload_max_filesize = 2M

max_input_time = 300

date.timezone = Asia/Kolkata

*******

Step 4) Download and install zabbix from source code for zabbix frontend (192.168.0.1)

[root@localhost ~]#groupadd zabbix

[root@localhost ~]#useradd -g zabbix –s /sbin/nologin zabbix

[root@localhost ~]#wget http://sourceforge.net/projects/zabbix/files/ZABBIX%20Latest%20Stable/2.0.6/zabbix-2.0.6.tar.gz                                                                                                                                                       

[root@localhost ~]#mv zabbix-2.0.6.tar.gz /opt/;cd /opt

[root@localhost ~]#tar -xvzf /opt/zabbix-2.0.6.tar.gz

[root@localhost ]#cd zabbix-2.0.0.6

[root@localhost ]#./configure --prefix=/opt/zabbix --enable-server --enable-agent --with-net-snmp --with-postgresql=/usr/pgsql-9.1/bin/pg_config --with-ssh2 --with-openipmi --with-libcurl

[root@localhost ]#make;make install

Step 5) Configure frontend

[root@localhost ~]#cp -R /opt/zabbix-2.0.6/frontends/php /var/www/html/zabbix

[root@localhost ~]#Service httpd restart

Step 5) Configure zabbix config files (192.168.0.1)

[root@localhost ]#vi /opt/zabbix/etc/zabbix_server.conf

*********

ListenPort=10051

LogFile=/opt/zabbix/log/zabbix_server.log

 PidFile=/opt/zabbix/log/zabbix_server.pid

 DBHost=192.168.0.2

DBName=zabbix

DBUser=zabbix

 DBPassword=zabbix

 StartPollers=10

 DisableHousekeeping=1

 CacheSize=128M

 HistoryCacheSize=128M

 TrendCacheSize=64M

 HistoryTextCacheSize=128M

 Timeout=30

***********

[root@localhost ]#vi /opt/zabbix/etc/zabbix_agentd.conf

************

LogFile=/tmp/zabbix_agentd.log

Server=127.0.0.1

ServerActive=127.0.0.1

Hostname=Zabbix server

************

Step 6) Import zabbix database to postgresql server

[root@localhost ]#cd /opt/zabbix-2.0.6/database/postgresql

 [root@localhost ]#   psql -U zabbix -h 192.168.0.2 -d zabbix -f schema.sql

  [root@localhost ]#psql -U zabbix -h 192.168.0.2 -d zabbix -f images.sql

  [root@localhost ]#psql -U zabbix -h 192.168.0.2 -d zabbix -f data.sql

Step 7) Installing Zabbix through web

Go to web browser and type below link

http://192.168.0.1/zabbix

Download the config file and paste it to the location /var/www/html/zabbix/conf/zabbix.conf.php

Step 7) Copy init script for zabbix_server and zabbix_agentd

[root@localhost ]#cp /root/zabbix.2.0.6/misc/init.d/fedora/core/zabbix_server /etc/init.d/

[root@localhost ]#cp /root/zabbix.2.0.6/misc/init.d/fedora/core/zabbix_agentd /etc/init.d/

[root@localhost ]#vi /etc/init.d/ zabbix_server

**************

# Zabbix-Directory

        BASEDIR=/opt/zabbix

        # Binary File

        BINARY_NAME=zabbix_server

        # Full Binary File Call

        FULLPATH=$BASEDIR/sbin/$BINARY_NAME

        # PID file

        PIDFILE=/opt/zabbix/log/$BINARY_NAME.pid

******************

[root@localhost ]#vi /etc/init.d/ zabbix_agentd

***************** 

        # Zabbix-Directory

        BASEDIR=/opt/zabbix

        # Binary File

        BINARY_NAME=zabbix_agentd

        # Full Binary File Call

        FULLPATH=$BASEDIR/sbin/$BINARY_NAME

        # PID file

        PIDFILE=/tmp/$BINARY_NAME.pid

************

[root@localhost ]# service zabbix_server restart

[root@localhost ]# service zabbix_agentd restart

Now You have done your installation part. Try to login with credentials 

URL: http://192.168.0.1/zabbix

User: Admin

Password: zabbix

sshpass, A great tool for non-interactive ssh login

Friend,

Recently I needed to perform some maintenance activity on some of my Linux machines.

I got a list of 100 Linux machine.

Problem was that, We haven't configured password-less SSH but the good point is that all Linux machine have same root password. :)

So First I installed "sshpass" command and wrapped ssh over ssh pass on a script.

Below is the sample script to get Uptime of all hosts
================
#!/bin/bash
for i in `cat /tmp/data.txt`
do
sshpass -p 'password' ssh -o StrictHostKeyChecking=no root@$i "hostname;uptime|awk '{print $3,$4}'" >>/tmp/uptime_detail_txt
done
===========================

Where  StrictHostKeyChecking is for disable host key checking

Installation and configuration HAproxy on CentOS

Step1)  Linux server has a development environment set up

yum update

yum -y groupinstall 'Development Tools'

Step 2) Download and uncompress haproxy from source code.

wget http://haproxy.1wt.eu/download/1.4/src/haproxy-1.4.23.tar.gz

tar xzf haproxy-1.4.23.tar.gz

 cd haproxy-1.4.23

 make TARGET=linux26

step3) copy the configuration files

mkdir /etc/haproxy

 cp haproxy /usr/sbin/haproxy

step 4) configure haproxy.cfg file according to your need.

vi /etc/haproxy.cfg

*********************

global

      maxconn 4096

      pidfile /var/run/haproxy.pid

      daemon

defaults

        log global

        option dontlognull

        balance leastconn

        clitimeout 60000

        srvtimeout 60000

        contimeout 5000

        retries 3

        option redispatch

listen exchange-http 10.10.3.156:80

      mode http

      stats enable

      stats uri /haproxy-stats

      balance source

      option forwardfor

      server cas1 10.10.3.145:80 check port 80 inter 20 rise 1 fall 1

      server cas2 10.10.3.146:80 check port 80 inter 20 rise 1 fall 1 backup

listen exchange-https-tr 10.10.3.156:444

        mode tcp

        balance source

        maxconn 10000

        server webserver1 10.10.3.145:444 check port 444 inter 20 rise 1 fall 1

        server webserver2 10.10.3.146:444 check port 444 inter 20 rise 1 fall 1 backup

listen exchange-https 10.10.3.156:443

        mode tcp

        balance source

        maxconn 10000

        server webserver1 10.10.3.145:443 check port 443 inter 20 rise 1 fall 1

        server webserver2 10.10.3.146:443 check port 443 inter 20 rise 1 fall 1 backup

listen exchange-https 10.10.3.156:25

        mode tcp

        balance source

        maxconn 10000

        server webserver1 10.10.3.145:25 check port 25 inter 20 rise 1 fall 1

        server webserver2 10.10.3.146:25 check port 25 inter 20 rise 1 fall 1 backup

Step 5) Start HAproxy as daemon

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

Step 6) If all goes well the create a init script for HAproxy

Vi /etc/init.d/haproxy

****************

#!/bin/sh

#

# chkconfig: - 85 15

# description: HA-Proxy is a TCP/HTTP reverse proxy which is particularly suited \

#              for high availability environments.

# processname: haproxy

# config: /etc/haproxy/haproxy.cfg

# pidfile: /var/run/haproxy.pid

# Script Author: Simon Matter <simon.matter@invoca.ch>

# Version: 2004060600

# Source function library.

if [ -f /etc/init.d/functions ]; then

  . /etc/init.d/functions

elif [ -f /etc/rc.d/init.d/functions ] ; then

  . /etc/rc.d/init.d/functions

else

  exit 0

fi

# Source networking configuration.

. /etc/sysconfig/network

# Check that networking is up.

[ ${NETWORKING} = "no" ] && exit 0

# This is our service name

BASENAME=`basename $0`

if [ -L $0 ]; then

  BASENAME=`find $0 -name $BASENAME -printf %l`

  BASENAME=`basename $BASENAME`

fi

[ -f /etc/$BASENAME/$BASENAME.cfg ] || exit 1

RETVAL=0

start() {

  /usr/sbin/$BASENAME -c -q -f /etc/$BASENAME/$BASENAME.cfg

  if [ $? -ne 0 ]; then

    echo "Errors found in configuration file, check it with '$BASENAME check'."

    return 1

  fi

  echo -n "Starting $BASENAME: "

  daemon /usr/sbin/$BASENAME -D -f /etc/$BASENAME/$BASENAME.cfg -p /var/run/$BASENAME.pid

  RETVAL=$?

  echo

  [ $RETVAL -eq 0 ] && touch /var/lock/subsys/$BASENAME

  return $RETVAL

}

stop() {

  echo -n "Shutting down $BASENAME: "

  killproc $BASENAME -USR1

  RETVAL=$?

  echo

  [ $RETVAL -eq 0 ] && rm -f /var/lock/subsys/$BASENAME

  [ $RETVAL -eq 0 ] && rm -f /var/run/$BASENAME.pid

  return $RETVAL

}

restart() {

  /usr/sbin/$BASENAME -c -q -f /etc/$BASENAME/$BASENAME.cfg

  if [ $? -ne 0 ]; then

    echo "Errors found in configuration file, check it with '$BASENAME check'."

    return 1

  fi

  stop

  start

}

reload() {

  /usr/sbin/$BASENAME -c -q -f /etc/$BASENAME/$BASENAME.cfg

  if [ $? -ne 0 ]; then

    echo "Errors found in configuration file, check it with '$BASENAME check'."

    return 1

  fi

  /usr/sbin/$BASENAME -D -f /etc/$BASENAME/$BASENAME.cfg -p /var/run/$BASENAME.pid -sf $(cat /var/run/$BASENAME.pid)

}

check() {

  /usr/sbin/$BASENAME -c -q -V -f /etc/$BASENAME/$BASENAME.cfg

}

rhstatus() {

  status $BASENAME

}

condrestart() {

  [ -e /var/lock/subsys/$BASENAME ] && restart || :

}

# See how we were called.

case "$1" in

  start)

    start

    ;;

  stop)

    stop

    ;;

  restart)

    restart

    ;;

  reload)

    reload

    ;;

  condrestart)

    condrestart

    ;;

  status)

    rhstatus

    ;;

  check)

    check

    ;;

  *)

    echo $"Usage: $BASENAME {start|stop|restart|reload|condrestart|status|check}"

    exit 1

esac

exit $?

chmod 755 /etc/init.d/haproxy

service haproxy restart

chkconfig haproxy on

Installation and configuration Heartbeat on Linux

Hi All,

Recently I implement Heartbeat for high Availability and ha-proxy for load balancing for four exchange servers in my office.

So, I took two Linux nodes (ex- 192.168.0.2 and 192.168.0.3) as a front to balance four exchange nodes (ex- 192.168.0.4, 192.168.0.5, 192.168.0.6, 192.168.0.7). We need to balance loads for ports (25, 110,993,995,80,443,587). We got a floating ip 192.268.0.1.

First I configured Heartbeat for High Availability of Linux nodes.

Below are steps for configuration

A.Node details are as follows

Node1 :

IpAddress(eth0):192.168.0.2(To send heartbeat signals to other nodes)

Node2 :

IpAddress(eth0):192.168.0.3(To send heartbeat signals to other nodes)

Step1 : Install the following packages in the same order which is shown.

Step1(a) : Install the following packages on node1

#rpm -ivh heartbeat-2.1.2-2.i386.rpm

#rpm -ivh heartbeat-ldirectord-2.1.2-2.i386.rpm

#rpm -ivh heartbeat-pils-2.1.2-2.i386.rpm

#rpm -ivh heartbeat-stonith-2.1.2-2.i386.rpm

Step1(b) : Install the following packages on node2

#rpm -ivh heartbeat-2.1.2-2.i386.rpm

#rpm -ivh heartbeat-ldirectord-2.1.2-2.i386.rpm

#rpm -ivh heartbeat-pils-2.1.2-2.i386.rpm

#rpm -ivh heartbeat-stonith-2.1.2-2.i386.rpm

Step2 : By default the main configuration files (ha.cf, haresources and authkeys) are not present in /etc/ha.d/ folder we have to copy these three files from /usr/share/doc/heartbeat-2.1.2 to /etc/ha.d/

Step2(a) : Copy main configuration files from /usr/share/doc/heartbeat-2.1.2 to /etc/ha.d/ on node 1

#cp /usr/share/doc/heartbeat-2.1.2/ha.cf /etc/ha.d/

#cp /usr/share/doc/heartbeat-2.1.2/haresources /etc/ha.d/

#cp /usr/share/doc/heartbeat-2.1.2/authkeys /etc/ha.d/

Step2(b) : Copy main configuration files from /usr/share/doc/heartbeat-2.1.2 to /etc/ha.d/ on node 2

#cp /usr/share/doc/heartbeat-2.1.2/ha.cf /etc/ha.d/

#cp /usr/share/doc/heartbeat-2.1.2/haresources /etc/ha.d/

#cp /usr/share/doc/heartbeat-2.1.2/authkeys /etc/ha.d/

Step3 : Edit ha.cf file

Step3(a) : Edit ha.cf file as follows on node1

********************************************

debugfile /var/log/ha-debug

logfile /var/log/ha-log

logfacility local0

keepalive 2

deadtime 25

warntime 10

initdead 50

udpport 694

bcast eth0

ucast eth0 192.168.0.2

auto_failback on

node station-x.example.com

node station-y.example.com

******************************

Step3(b) : Edit ha.cf file as follows on node2

*****************************

debugfile /var/log/ha-debug

logfile /var/log/ha-log

logfacility local0

keepalive 2

deadtime 25

warntime 10

initdead 50

udpport 694

bcast eth0

ucast eth0 192.168.0.3

auto_failback on

node station-x.example.com

node station-y.example.com

********************************

Step4 : Edit haresources file

Step4(a) : Just specify below entry in last line of this file on node1

station-x.example.com 192.268.0.1

Step4(b) : Just specify below entry in last line of this file on node2

station-x.example.com 192.268.0.1

Step5 (a) : Edit authkeys file on node1

#vi /etc/ha.d/authkeys

auth 2

#1 crc

2 sha1 HI!

#3 md5 Hello!

Now save and exit the file

Step5 (b) : Edit authkeys file on node2

#vi /etc/ha.d/authkeys

auth 2

#1 crc

2 sha1 HI!

#3 md5 Hello!

Step6 : Edit /etc/hosts file to give entries of host-names for the nodes

Step6(a) : Edit /etc/hosts file on node1 as below

192.268.0.2 station-x.example.com station-x

192.168.0.3 station-y.example.com station-y

Step6(b) : Edit /etc/hosts file on node2 as below

192.268.0.2 station-x.example.com station-x

192.168.0.3 station-y.example.com station-y

Step7 : Start Heartbeat cluster

Step7(a) : Start heartbeat cluster on node1

#service heartbeat start

Step7(b) : Start heartbeat cluster on node2

#service heartbeat start

Note:

1)      If on starting Heartbeat you are getting hostname error, then please set proper hostname for both nodes

2)      Checking your Heartbeat cluster:

If your heartbeat cluster is running fine a Virtual Ethernet Interface is created on node1.

# ifconfig

eth0      Link encap:Ethernet  HWaddr 08:00:27:0B:31:59

          inet addr:192.168.0.2  Bcast:192.168.0.255  Mask:255.255.255.0

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

          RX packets:25035 errors:0 dropped:0 overruns:0 frame:0

          TX packets:13080 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:1000

          RX bytes:7108268 (6.7 MiB)  TX bytes:11011415 (10.5 MiB)

eth0:0    Link encap:Ethernet  HWaddr 08:00:27:0B:31:59

          inet addr:192.168.0.1  Bcast:192.168.0.255  Mask:255.255.255.0

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

MySQL master-master replication and auto-increment indexes

Hi Friends,

Recently I implemented mysql maste-master replication along with Heartbeat for high availability for our monitoring tool Zabbix.

So In this blog I am sharing master-master replication. I will discuss Hartbeat in my next blogs.

Please check below steps:

Step 1) Master 2 changes to /etc/my.cnf:

1.  [mysqld]

2.  datadir=/var/lib/mysql

3.  socket=/var/lib/mysql/mysql.sock

4.  old_passwords=1

5.   

6.  log-bin

7.  binlog-do-db=zabbix  # input the database which should be replicated

8.  binlog-ignore-db=mysql            # input the database that should be ignored for replication

9.  binlog-ignore-db=test

10.  

11. server-id=2

12. auto_increment_increment= 2 #For Auto-increment

13. auto_increment_offset   = 2

14.  

15. [mysql.server]

16. user=mysql

17. basedir=/var/lib

18.  

19.  

20. [mysqld_safe]

21. err-log=/var/log/mysqld.log

22. pid-file=/var/run/mysqld/mysqld.pid

Step 2) Master 1 changes to /etc/my.cnf:

1.  [mysqld]

2.  datadir=/var/lib/mysql

3.  socket=/var/lib/mysql/mysql.sock

4.  old_passwords=1

5.   

6.  log-bin

7.  binlog-do-db=zabbix  # input the database which should be replicated

8.  binlog-ignore-db=mysql            # input the database that should be ignored for replication

9.  binlog-ignore-db=test

10. server-id=1

11. auto_increment_increment= 2 #For auto-increments

12. auto_increment_offset   = 1

13.  

14. [mysql.server]

15. user=mysql

16. basedir=/var/lib

17.  

18. [mysqld_safe]

19. err-log=/var/log/mysqld.log

20. pid-file=/var/run/mysqld/mysqld.pid

Step 3) Restarting Mysql on both servers

#Service mysql restart

Step 4) Create a replication slave account on Master 2 for Master 1

mysql> grant replication slave on zabbix.* to 'zabbix'@’%’ identified by 'password';

And start master:

1.  mysql> start master;

Step 5) On master 2

1.  mysql> show master status;

2.  +------------------------+----------+--------------+------------------+

3.  | File                   | Position | Binlog_Do_DB | Binlog_Ignore_DB |

4.  +------------------------+----------+--------------+------------------+

5.  |mysqld-bin.000012       |      106 | zabbix            |     mysql,test   |

6.  +------------------------+----------+--------------+------------------+

7.  1 row in set (0.00 sec)

Step 6) On master 1:

1.  mysql> stop slave;

2.  mysql> CHANGE MASTER TO MASTER_HOST='192.168.0.5', MASTER_USER='zabbix', MASTER_PASSWORD='password', MASTER_PORT=3306,MASTER_LOG_FILE='mysqld-bin.000012', MASTER_LOG_POS=106, MASTER_CONNECT_RETRY=10;

3.  mysql> start slave;

Step 7) On master 1

8.  mysql> show master status;

9.  +------------------------+----------+--------------+------------------+

10. | File                   | Position | Binlog_Do_DB | Binlog_Ignore_DB |

11. +------------------------+----------+--------------+------------------+

12. |mysqld-bin.000015       |      106 | zabbix            |     mysql,test   |

13. +------------------------+----------+--------------+------------------+

14. 1 row in set (0.00 sec)

Step 8) On master 2:

4.  mysql> stop slave;

5.  mysql> CHANGE MASTER TO MASTER_HOST='192.168.0.4', MASTER_USER='zabbix', MASTER_PASSWORD='password', MASTER_PORT=3306,MASTER_LOG_FILE='mysqld-bin.000015', MASTER_LOG_POS=106, MASTER_CONNECT_RETRY=10;

6.  mysql> start slave;

Note: You could check slave status from masters by executing below command

mysql>show slave status\G;