MHA introduction

(1) Introduction

(2) The software consists of two parts

(3) How it works

Experimental environment

(1) Requirements:

In this case, it is required to monitor MySQL database through MHA to switch automatically in case of failure, without affecting the business.

(2) Ideas:

Install MySQL database
 Configure MySQL one master and two slaves
 Install MHA software
 Configure password free authentication
 Configure MySQL and MHA high availability
 Simulate master failover

(3) Operating system:

Cent0S7.6, MHA 0.57

1. Install mysql database on three primary and secondary servers (the same operation, only one is demonstrated)

#Install build dependent environment
[root@master ~] yum -y install gcc gcc-c++ ncurses ncurses-devel bison perl-Module-Install cmake
[root@master ~]# mount.cifs //192.168.100.100/tools /mnt/tools / ාාmount Toolkit
Password for root@//192.168.100.100/tools:   
[root@master ~]# cd /mnt/tools/MHA/
[root@master MHA]# tar xf cmake-2.8.6.tar.gz -C /opt/   ##decompression
[root@master mnt] cd /opt/cmake-2.8.6/
[root@master MHA]# cd /opt/cmake-2.8.6/   ##To configure
[root@master cmake-2.8.6] gmake && gmake install   ##Compilation and installation
#Install mysql database
[root@master cmake-2.8.6]# cd /mnt/tools/MHA/
[root@master MHA]# tar xf mysql-5.6.36.tar.gz -C /opt/t ##Decompression MySQL
#Compile mysql
[root@master MHA]# cd /opt/mysql-5.6.36/
[root@master mysql-5.6.36]# cmake -DCMAKE_INSTALL_PREFIX=/usr/local/mysql \
-DDEFAULT_CHARSET=utf8 \     ##Specify character set
-DDEFAULT_COLLATION=utf8_general_ci \     ##Specify character set defaults
-DWITH_EXTRA_CHARSETS=all \  ##Associate all additional character sets
-DSYSCONFDIR=/etc    ##Profile directory
#install
[root@master mysql-5.6.36]# make && make install  ##Compilation and installation
#Setting environment variables
[root@master mysql-5.6.36]# cp support-files/my-default.cnf /etc/my.cnf  ##Copy profile
[root@master mysql-5.6.36]# cp support-files/mysql.server /etc/rc.d/init.d/mysqld 
##Copy startup script
[root@master mysql-5.6.36]# chmod +x /etc/rc.d/init.d/mysqld  ##Give execution permission
[root@master mysql-5.6.36]# chkconfig --add mysqld  ##Add to service management
[root@master mysql-5.6.36]# echo "PATH=$PATH:/usr/local/mysql/bin" >> /etc/profile
##Modify environment variables
[root@master mysql-5.6.36]# source /etc/profile   ##Refresh Huaning variable
#Create mysql database and authorize
[root@master mysql-5.6.36]# groupadd mysql   ##Create group
[root@master mysql-5.6.36]# useradd -M -s /sbin/nologin mysql -g mysql  
##Create system user
[root@master mysql-5.6.36]# chown -R mysql.mysql /usr/local/mysql  ##Modify the owner
[root@master mysql-5.6.36]# mkdir -p /data/mysql  ##Create data directory
#Initialize database
[root@master mysql-5.6.36]# /usr/local/mysql/scripts/mysql_install_db \
--basedir=/usr/local/mysql \  ##File directory
--datadir=/usr/local/mysql/data \  ##Data directory
--user=mysql   ##user

2. Modify the main configuration file of mysql / etc/my.cnf. Note that the server IDs of the three servers cannot be the same

##To configure the primary server:
[root@master mysql-5.6.36]# vim /etc/my.cnf
[mysql]
server-id = 1
#Open binary log
log_bin = master-bin
#Allow synchronization from server
log-slave-updates = true

##Configure slave 1:
[root@slave1 mysql-5.6.36]# vim /etc/my.cnf
[mysql]
server-id = 2
#Open binary log
log_bin = master-bin
 #Use relay logs for synchronization
relay-log = relay-log-bin
relay-log-index = slave-relay-bin.index

##Configure slave 2:
[root@slave2 mysql-5.6.36]# vim /etc/my.cnf
[mysql]
server-id = 3
log_bin = master-bin
relay-log = relay-log-bin
relay-log-index = slave-relay-bin.index

3. Three servers start mysql service

#Create these two soft links on three servers
[root@master mysql-5.6.36]# ln -s /usr/local/mysql/bin/mysql /usr/sbin/
[root@master mysql-5.6.36]# ln -s /usr/local/mysql/bin/mysqlbinlog /usr/sbin/

#mysql start
[root@master mysql-5.6.36]# /usr/local/mysql/bin/mysqld_safe --user=mysql &
#Turn off firewall and security features
[root@master mysql-5.6.36]# systemctl stop firewalld.service
[root@master mysql-5.6.36]# setenforce 0

4, Configure Mysql master slave synchronization (one master and two slaves) to authorize two users on all database nodes

[root@master mysql-5.6.36]# mysql -u root -p / / enter the database
mysql> grant replication slave on *.* to 'myslave'@'192.168.52.%' identified by '123';
##Synchronize user myslave from database
mysql> grant all privileges on *.* to 'mha'@'192.168.52.%' identified by 'manager';
##manager uses to monitor users
mysql> flush privileges;  //Refresh database
#Add the following authorization (not required in theory) to the database as hostname authorization (in the form of hostname when MHA checks)
mysql> grant all privileges on *.* to 'mha'@'master' identified by 'manager';
mysql> grant all privileges on *.* to 'mha'@'slave1' identified by 'manager';
mysql> grant all privileges on *.* to 'mha'@'slave2' identified by 'manager';

5. Viewing binaries and synchronization points on the master server

mysql> show master status;
+-------------------+----------+--------------+------------------+-------------------+
| File              | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+-------------------+----------+--------------+------------------+-------------------+
| master-bin.000001 |     1213 |              |                  |                   |
+-------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)

6. Set up synchronization on two slave servers

#Execute the following commands on both slave servers to synchronize the logs of the primary server
mysql>  change master to master_host='192.168.52.129',master_user='myslave',master_password='123',master_log_file='master-bin.000001',master_log_pos=1213;
mysql>  start slave;    //Open slave
mysql> show slave status\G;  //View slave
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
mysql> set global read_only=1;
mysql> flush privileges;   //Refresh database

7. Install the MHA lazy environment on all servers. First install the epel source

[root@master mysql-5.6.36]# yum install epel-release --nogpgcheck -y  ##Installation source
[root@master mysql-5.6.36]# yum install -y perl-DBD-MySQL \  ##Aiming at MySQL
perl-Config-Tiny \  ##configuration file
perl-Log-Dispatch \   ##Journal
perl-Parallel-ForkManager \  ##Multithreading management
perl-ExtUtils-CBuilder \    ##Extension tool
perl-ExtUtils-MakeMaker \  
perl-CPAN  ##Program library

8. Install node s on all servers

#Unzip and install node
[root@manager ~]# cd ~
[root@manager ~]# tar zxvf /mnt/mha4mysql-node-0.57.tar.gz
[root@manager ~]# cd mha4mysql-node-0.57/
[root@manager mha4mysql-node-0.57]# perl Makefile.PL  ##perl to compile
[root@manager mha4mysql-node-0.57]# make && make install  ##Compilation and installation

9. Install manager on manger server (Note: you must install node component to install manager component)

#Turn off firewall
[root@manager ~]# systemctl stop firewalld.service 
[root@manager ~]# setenforce 0
#Unzip and install manager
[root@manager ~]# cd ~
[root@manager ~]# tar zxvf /mnt/mha4mysql-manager-0.57.tar.gz
[root@manager ~]# cd mha4mysql-manager-0.57/
[root@manager mha4mysql-manager-0.57]# perl Makefile.PL   ##perl compilation
[root@manager mha4mysql-manager-0.57]# make && make install   ##Compilation and installation

manager After the server is installed usr/local/bin Several tools will be generated under the directory:

 - masterha_check_repl      inspect mysql Replication status
 - masterha_master_monitor       inspect master Is it down?
 - masterha_check_ssh   inspect MHA Of SSH Configuration situation  
 - masterha_master_switch     Control failover
 - masterha_check_status         Check current MHA running state
 -  masterha_conf_host        Add or remove configured server information
 - masterha_stop                Close manager
 - masterha_manager                     start-up manager Script

node After installation/usr/local/bin The following scripts are generated (usually by MHA Manager No manual operation is required)

 - apply_diff_relay_logs : Identify differentiated relay log events and apply them to other slave；
 - save_binary_logs: Save and copy master Binary log of;
 - filter_mysqlbinlog : Remove unnecessary ROLLBACK Event ( MHA The tool is no longer used);
 - purge_relay_logs: Clear relay log (no blocking SQL Thread);

10. Configure password free access

##Configure password free authentication of all database nodes in manager
[root@manager ~]# ssh-keygen -t rsa  ##Generate secret key
Enter file in which to save the key (/root/.ssh/id_rsa):   ##Enter
Enter passphrase (empty for no passphrase):   ##Enter
Enter same passphrase again:    ##Enter
[root@manager ~]# ssh-copy-id 192.168.52.129  ##Upload to other servers
Are you sure you want to continue connecting (yes/no)? yes
root@192.168.52.129's password:    ##Enter password for 129 server
[root@manager ~]# ssh-copy-id 192.168.52.130
[root@manager ~]# ssh-copy-id 192.168.52.131
##Configure password free authentication to database nodes slave1 and slave2 on master
[root@master ~]# ssh-keygen -t rsa
[root@master ~]# ssh-copy-id 192.168.52.130
[root@master ~]# ssh-copy-id 192.168.52.131
##Password free authentication configured to database nodes master 'and slave 2 on slave 1
[root@slave1 ~]# ssh-keygen -t rsa
[root@slave1 ~]# ssh-copy-id 192.168.52.129
[root@slave1 ~]# ssh-copy-id 192.168.52.131
##Configure password free authentication to database nodes slave1 and master on slave2
[root@slave2 ~]# ssh-keygen -t rsa
[root@slave2 ~]# ssh-copy-id 192.168.52.129
[root@slave2 ~]# ssh-copy-id 192.168.52.130

11. Configure MHA, copy related scripts to / usr/local directory on manager node, and configure

[root@manager ~]# cp -ra /root/mha4mysql-manager-0.57/samples/scripts/ /usr/local/bin/
##Copy script to / usr/local
[root@manager ~]# ls mha4mysql-manager-0.57/samples/scripts/
 ##Generate four executable scripts
 master_ip_failover: When switching automatically VIP Managed scripts;
 master_ip_online_change: When switching Online VIP Management;
 power_manager: Script to shut down the host after failure;
 send_report: Send alarm script after failover;
##Copy the script of VIP management during automatic switch to the directory / usr/local/bin /
[root@manager ~]# cp /usr/local/bin/scripts/master_ip_failover /usr/local/bin/
[root@manager ~]# vim /usr/local/bin/master_ip_failover   
##Delete all content and rewrite the master IP failover script
#!/usr/bin/env perl
use strict;
use warnings FATAL => 'all';

use Getopt::Long;

my (
$command, $ssh_user, $orig_master_host, $orig_master_ip,
$orig_master_port, $new_master_host, $new_master_ip, $new_master_port
);
my $vip = '192.168.52.100';
my $brdc = '192.168.52.255';
my $ifdev = 'ens33';
my $key = '1';
my $ssh_start_vip = "/sbin/ifconfig ens33:$key $vip";
my $ssh_stop_vip = "/sbin/ifconfig ens33:$key down";
my $exit_code = 0;
#my $ssh_start_vip = "/usr/sbin/ip addr add $vip/24 brd $brdc dev $ifdev label $ifdev:$key;/usr/sbin/arping -q -A -c 1 -I $ifdev $vip;iptables -F;";
#my $ssh_stop_vip = "/usr/sbin/ip addr del $vip/24 dev $ifdev label $ifdev:$key";
GetOptions(
'command=s' => \$command,
'ssh_user=s' => \$ssh_user,
'orig_master_host=s' => \$orig_master_host,
'orig_master_ip=s' => \$orig_master_ip,
'orig_master_port=i' => \$orig_master_port,
'new_master_host=s' => \$new_master_host,
'new_master_ip=s' => \$new_master_ip,
'new_master_port=i' => \$new_master_port,
);

exit &main();

sub main {

print "\n\nIN SCRIPT TEST====$ssh_stop_vip==$ssh_start_vip===\n\n";

if ( $command eq "stop" || $command eq "stopssh" ) {

my $exit_code = 1;
eval {
print "Disabling the VIP on old master: $orig_master_host \n";
&stop_vip();
$exit_code = 0;
};
if ($@) {
warn "Got Error: $@\n";
exit $exit_code;
}
exit $exit_code;
}
elsif ( $command eq "start" ) {

my $exit_code = 10;
eval {
print "Enabling the VIP - $vip on the new master - $new_master_host \n";
&start_vip();
$exit_code = 0;
};
if ($@) {
warn $@;
exit $exit_code;
}
exit $exit_code;
}
elsif ( $command eq "status" ) {
print "Checking the Status of the script.. OK \n";
exit 0;
}
else {
&usage();
exit 1;
}
}
sub start_vip() {
`ssh $ssh_user\@$new_master_host \" $ssh_start_vip \"`;
}
# A simple system call that disable the VIP on the old_master
sub stop_vip() {
`ssh $ssh_user\@$orig_master_host \" $ssh_stop_vip \"`;
}

sub usage {
print
"Usage: master_ip_failover --command=start|stop|stopssh|status --orig_master_host=host --orig_master_ip=ip --orig_master_port=port --new_master_host=host --new_master_ip=ip --new_master_port=port\n";
}

12. Create the MHA software directory on the manager node and copy the configuration file

[root@manager ~]# mkdir /etc/masterha
[root@manager ~]# cp /root/mha4mysql-manager-0.57/samples/conf/app1.cnf /etc/masterha/
#Edit profile
[root@manager ~]# vim /etc/masterha/app1.cnf
[server default]
#manager Profile
manager_log=/var/log/masterha/app1/manager.log     
#manager log
manager_workdir=/var/log/masterha/app1
#The location where the master saves the binlog. The path here should be the same as that of the bilog configured in the master
master_binlog_dir=/usr/local/mysql/data
#Set the switch script for automatic failover. That's the script above
master_ip_failover_script=/usr/local/bin/master_ip_failover
#Set the switch script for manual switch
master_ip_online_change_script=/usr/local/bin/master_ip_online_change
#This password is the one used to create the monitoring user
password=manager
remote_workdir=/tmp
#Set copy user password
repl_password=123
#Set users for replication users
repl_user=myslave
#Set the script of alarm after switching
secondary_check_script=/usr/local/bin/masterha_secondary_check -s 192.168.52.130 -s 192.168.52.131
#Set failure shutdown failure script host
shutdown_script=""
#Set the login user name of ssh
ssh_user=root
#Set monitoring user
user=mha

[server1]
hostname=192.168.52.129
port=3306

[server2]
candidate_master=1
#Set as candidate master. If this parameter is set, the sender will upgrade from the slave to the master after the master-slave switch
hostname=192.168.52.130
check_repl_delay=0
port=3306

[server3]
hostname=192.168.52.131
port=3306

13. Test ssh without password authentication. If it is normal, it will output successful and check the health status

[root@manager ~]# masterha_check_ssh -conf=/etc/masterha/app1.cnf
........//Ellipsis content
[root@manager ~]# masterha_check_repl -conf=/etc/masterha/app1.cnf

14. Configure virtual ip on the master

[root@master mha4mysql-node-0.57]# /sbin/ifconfig ens33:1 192.168.52.100/24

15. Start mha on the manager server

[root@manager scripts]# nohup masterha_manager --conf=/etc/masterha/app1.cnf --remove_dead_master_conf --ignore_last_failover < /dev/null > /var/log/masterha/app1/manager.log 2>&1 &
##Viewing the MHA status, you can see that the current master is a mysql node
[root@manager scripts]# masterha_check_status --conf=/etc/masterha/app1.cnf
app1 (pid:43036) is running(0:PING_OK), master:192.168.52.129

16. Fault simulation

[root@manager scripts]# tailf /var/log/masterha/app1/manager.log   
##Start monitoring observation logging

##Turn off the master server
[root@master mha4mysql-node-0.57]# pkill -9 mysql

//You can see the status of the slave database. vip will switch to one of the slave databases:

[root@slave1 mha4mysql-node-0.57]# ifconfig 
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
                inet 192.168.52.130  netmask 255.255.255.0  broadcast 192.168.52.255

ens33:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
                inet 192.168.52.100  netmask 255.255.255.0  broadcast 192.168.52.255
                ether 00:0c:29:af:94:06  txqueuelen 1000  (Ethernet)

//At this time, install mysql on the manager, and the client can also connect to the database through the virtual ip:

##Lifting rights on vip's database server
mysql> grant all on *.* to 'root'@'%' identified by 'abc123';
Query OK, 0 rows affected (0.00 sec)
##Log in with virtual ip on the client
[root@manager ~]# mysql -uroot -h 192.168.52.100 -p  ##Specify virtual ip
Enter password:   ##Input password

MySQL [(none)]>