一、MHA相关知识
1.1 什么是mha
MHA(MasterHigh Availability)是一套优秀的MySQL高可用环境下故障切换和主从复制的软件。
MHA 的出现就是解决MySQL 单点的问题。
MySQL故障切换过程中,MHA能做到0-30秒内自动完成故障切换操作。
MHA能在故障切换的过程中最大程度上保证数据的一致性,以达到真正意义上的高可用。
1.2 mha的组成
MHA Node(数据节点)
MHA Node 运行在每台 MySQL 服务器上。
MHA Manager(管理节点)
MHA Manager 可以单独部署在一台独立的机器上,管理多个 master-slave 集群;也可以部署在一台 slave 节点上。
MHA Manager 会定时探测集群中的 master 节点。当 master 出现故障时,它可以自动将最新数据的 slave 提升为新的 master, 然后将所有其他的 slave 重新指向新的 master。整个故障转移过程对应用程序完全透明。
1.3 mha的特点
自动故障切换过程中,MHA试图从宕机的主服务器上保存二进制日志,最大程度的保证数据不丢失
使用半同步复制,可以大大降低数据丢失的风险,如果只有一个slave已经收到了最新的二进制日志,MHA可以将最新的二进制日志应用于其他所有的slave服务器上,因此可以保证所有节点的数据一致性
目前MHA支持一主多从架构,最少三台服务,即一主两从
1.4 MHA 原理
MHA Node 运行在每台 MySOL 服务器上,MHA Manager 会定时探测集群中的 master 节点,当 master 出现故障时,它可以自动将最新数据的 slave 提升为新的 master,然后将所有其他的 slave 重新指向新的 master。整个故障转移过程对客户端应用程序完全透明。
二、MHA的搭建
2.1 mha架构
2.1.1 数据库的安装
[Linux] MySQL数据表(数据结构)管理-CSDN博客https://blog.csdn.net/Cnm_147258/article/details/135157721?spm=1001.2014.3001.5502具体操作过程请参考我之前的博客
2.1.2 一主两从的设置
(1)修改 Master、Slave1、Slave2 节点的主机名
hostnamectl set-hostname mysql1
hostnamectl set-hostname mysql2
hostnamectl set-hostname mysql3
(2)修改 Master、Slave1、Slave2 节点的 Mysql主配置文件/etc/my.cnf
[client]
port = 3306
socket=/usr/local/mysql/mysql.sock
[mysql]
port = 3306
socket = /usr/local/mysql/mysql.sock
auto-rehash
[mysqld]
user = mysql
basedir=/usr/local/mysql
datadir=/usr/local/mysql/data
port = 3306
character-set-server=utf8
pid-file = /usr/local/mysql/mysqld.pid
socket=/usr/local/mysql/mysql.sock
bind-address = 0.0.0.0
skip-name-resolve
max_connections=4096
default-storage-engine=INNODB
max_allowed_packet=32M
server-id = 1
log_bin = mysql-bin
binlog_format = mixed
log-slave-updates = true
relay-log = relay-log-bin
relay-log-index = slave-relay-bin.index
sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_AUTO_VALUE_ON_ZERO,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,PIPES_AS_CONCAT,ANSI_QUOTES
[client]
port = 3306
socket=/usr/local/mysql/mysql.sock
[mysql]
port = 3306
socket = /usr/local/mysql/mysql.sock
auto-rehash
[mysqld]
user = mysql
basedir=/usr/local/mysql
datadir=/usr/local/mysql/data
port = 3306
character-set-server=utf8
pid-file = /usr/local/mysql/mysqld.pid
socket=/usr/local/mysql/mysql.sock
bind-address = 0.0.0.0
skip-name-resolve
max_connections=4096
default-storage-engine=INNODB
max_allowed_packet=32M
server-id = 2
log_bin = mysql-bin
binlog_format = mixed
log-slave-updates = true
relay-log = relay-log-bin
relay-log-index = slave-relay-bin.index
sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_AUTO_VALUE_ON_ZERO,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,PIPES_AS_CONCAT,ANSI_QUOTES
[client]
port = 3306
socket=/usr/local/mysql/mysql.sock
[mysql]
port = 3306
socket = /usr/local/mysql/mysql.sock
auto-rehash
[mysqld]
user = mysql
basedir=/usr/local/mysql
datadir=/usr/local/mysql/data
port = 3306
character-set-server=utf8
pid-file = /usr/local/mysql/mysqld.pid
socket=/usr/local/mysql/mysql.sock
bind-address = 0.0.0.0
skip-name-resolve
max_connections=4096
default-storage-engine=INNODB
max_allowed_packet=32M
server-id = 3
log_bin = mysql-bin
binlog_format = mixed
log-slave-updates = true
relay-log = relay-log-bin
relay-log-index = slave-relay-bin.index
sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_AUTO_VALUE_ON_ZERO,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,PIPES_AS_CONCAT,ANSI_QUOTES
systemctl restart mysqld
(3)在 Master、Slave1、Slave2 节点上都创建两个软链接
ln -s /usr/local/mysql/bin/mysql /usr/sbin/
ln -s /usr/local/mysql/bin/mysqlbinlog /usr/sbin/
(4) 配置 mysql 一主两从
mysql -uroot -pabc123
grant replication slave on *.* to 'myslave'@'192.168.136.%' identified by 'abc123'; #从数据库同步使用
grant all privileges on *.* to 'mha'@'192.168.136.%' identified by 'manager'; #manager 使用
grant all privileges on *.* to 'mha'@'mysql1' identified by 'manager'; #防止从库通过主机名连接不上主库
grant all privileges on *.* to 'mha'@'mysql2' identified by 'manager';
grant all privileges on *.* to 'mha'@'mysql3' identified by 'manager';
flush privileges;
(5)在 Master 节点查看二进制文件和同步点
(6)在 Slave1、Slave2 节点执行同步操作
change master to master_host='192.168.136.150',master_user='myslave',master_password='abc123',master_log_file='mysql-bin.000008',master_log_pos=154;
start slave;
(7)在 Slave1、Slave2 节点查看数据同步结果
show slave status\G
//确保 IO 和 SQL 线程都是 Yes,代表同步正常。
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
(8)两个从库必须设置为只读模式:
set global read_only=1;
(9)插入数据测试数据库同步
create database cxk;
use cxk;
create table cxk1(id int primary key, name varchar(20), sex char(2));
insert into cxk1 values (1,'kun','女');
insert into cxk1 values (2,'xhz','男');
show databases;
select * from cxk.cxk1;
2.1.3 MHA搭建
(1)安装 MHA 软件
#所有服务器上都安装 MHA 依赖的环境,首先安装 epel 源
yum install epel-release --nogpgcheck -y
yum install -y perl-DBD-MySQL \
perl-Config-Tiny \
perl-Log-Dispatch \
perl-Parallel-ForkManager \
perl-ExtUtils-CBuilder \
perl-ExtUtils-MakeMaker \
perl-CPAN
(2)安装 MHA 软件包
cd /opt
tar zxvf mha4mysql-node-0.57.tar.gz
cd mha4mysql-node-0.57
perl Makefile.PL
make && make install
cd /opt
tar zxvf mha4mysql-manager-0.57.tar.gz
cd mha4mysql-manager-0.57
perl Makefile.PL
make && make install
(3)在所有服务器上配置无密码认证
在 manager 节点上配置到所有数据库节点的无密码认证
ssh-keygen -t rsa #一路按回车键
ssh-copy-id 192.168.80.150
ssh-copy-id 192.168.80.160
ssh-copy-id 192.168.80.170
在 mysql1 上配置到数据库节点 mysql2 和 mysql3 的无密码认证
ssh-keygen -t rsa
ssh-copy-id 192.168.80.160
ssh-copy-id 192.168.80.170
在 mysql2 上配置到数据库节点 mysql1 和 mysql3 的无密码认证
ssh-keygen -t rsa
ssh-copy-id 192.168.80.150
ssh-copy-id 192.168.80.170
在 mysql3 上配置到数据库节点 mysql1 和 mysql2 的无密码认证
ssh-keygen -t rsa
ssh-copy-id 192.168.80.150
ssh-copy-id 192.168.80.160
(4)在 manager 节点上配置 MHA
在 manager 节点上复制相关脚本到/usr/local/bin 目录
cp -rp /opt/mha4mysql-manager-0.57/samples/scripts /usr/local/bin
//拷贝后会有四个执行文件
ll /usr/local/bin/scripts/
(5)复制上述的自动切换时 VIP 管理的脚本到 /usr/local/bin 目录,这里使用master_ip_failover脚本来管理 VIP 和故障切换
cp /usr/local/bin/scripts/master_ip_failover /usr/local/bin
(6)修改内容如下:(删除原有内容,直接复制并修改vip相关参数。可在拷贝前输入 :set paste 解决vim粘贴乱序问题)
#!/usr/bin/env perl
use strict;
use warnings FATAL => 'all';
use Getopt::Long;
my (
$command, $orig_master_host, $orig_master_ip,$ssh_user,
$orig_master_port, $new_master_host, $new_master_ip,$new_master_port,
$orig_master_ssh_port,$new_master_ssh_port,$new_master_user,$new_master_password
);
# 这里定义的虚拟IP配置要注意,这个ip必须要与你自己的集群在同一个网段,否则无效
my $vip = '192.168.136.200/24';
my $key = '1';
# 这里的网卡名称 “ens33” 需要根据你机器的网卡名称进行修改
# 如果多台机器直接的网卡名称不统一,有两种方式,一个是改脚本,二是把网卡名称修改成统一
# 我这边实际情况是修改成统一的网卡名称
my $ssh_start_vip = "sudo /sbin/ifconfig ens33:$key $vip";
my $ssh_stop_vip = "sudo /sbin/ifconfig ens33:$key down";
my $ssh_Bcast_arp= "sudo /sbin/arping -I ens33 -c 3 -A $vip";
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,
'orig_master_ssh_port=i' => \$orig_master_ssh_port,
'new_master_host=s' => \$new_master_host,
'new_master_ip=s' => \$new_master_ip,
'new_master_port=i' => \$new_master_port,
'new_master_ssh_port' => \$new_master_ssh_port,
'new_master_user' => \$new_master_user,
'new_master_password' => \$new_master_password
);
exit &main();
sub main {
$ssh_user = defined $ssh_user ? $ssh_user : 'root';
print "\n\nIN SCRIPT TEST====$ssh_user|$ssh_stop_vip==$ssh_user|$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();
&start_arp();
$exit_code = 0;
};
}
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 \"`;
}
sub stop_vip() {
`ssh $ssh_user\@$orig_master_host \" $ssh_stop_vip \"`;
}
sub start_arp() {
`ssh $ssh_user\@$new_master_host \" $ssh_Bcast_arp \"`;
}
sub usage {
print
"Usage: master_ip_failover --command=start|stop|stopssh|status --ssh_user=user --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";
}
(7)创建 MHA 软件目录并拷贝配置文件,这里使用app1.cnf配置文件来管理 mysql 节点服务器
#创建相关目录(所有节点)
mkdir -p /opt/mysql-mha/mha-node
# manager节点
mkdir -p /opt/mysql-mha/mha
#编写配置文件
vim /opt/mysql-mha/mysql_mha.cnf
[server default]
manager_log=/opt/mysql-mha/manager.log
manager_workdir=/opt/mysql-mha/mha
master_binlog_dir=/usr/local/mysql/data
master_ip_failover_script=/usr/local/bin/master_ip_failover
master_ip_online_change_script=/usr/local/bin/master_ip_online_change
password=manager
ping_interval=1
port=3306
remote_workdir=/opt/mysql-mha/mha-node
repl_password=abc123
repl_user=myslave
secondary_check_script=/usr/local/bin/masterha_secondary_check -s 192.168.136.160 -s 192.168.136.170
shutdown_script=""
ssh_user=root
user=mha
[server2]
candidate_master=1
check_repl_delay=0
hostname=192.168.136.160
port=3306
[server3]
hostname=192.168.136.170
port=3306
(8)第一次配置需要在 Master 节点上手动开启虚拟IP
ifconfig ens33:1 192.168.80.200/24
(9)在 manager 节点上测试 ssh 无密码认证,如果正常最后会输出 successfully,如下所示
masterha_check_ssh -conf=/opt/mysql-mha/mysql_mha.cnf
(10)在 manager 节点上测试 mysql 主从连接情况,最后出现 MySQL Replication Health is OK 字样说明正常。如下所示。
masterha_check_repl -conf=/opt/mysql-mha/mysql_mha.cnf
(11)在 manager 节点上启动 MHA
nohup masterha_manager \
--conf=/opt/mysql-mha/mysql_mha.cnf \
--remove_dead_master_conf \
--ignore_last_failover < /dev/null > /var/log/mha_manager.log 2>&1 &
(12)查看 MHA 状态,可以看到当前的 master 是 mysql1 节点
masterha_check_status --conf=/opt/mysql-mha/mysql_mha.cnf
(13)查看 MHA 日志,也以看到当前的 master 是 192.168.80.10,如下所示
cat /opt/mysql-mha/manager.log | grep "current master"
(14)查看 mysql1 的 VIP 地址 192.168.80.200 是否存在,这个 VIP 地址不会因为 manager 节点停止 MHA 服务而消失
ifconfig
2.2 故障模拟
2.2.1 主库失效
2.2.2 备选库成为主库
2.2.3 原故障主库恢复重新加入到MHA成为从库
(1)修复mysql
systemctl restart mysqld
(2)修复主从
#在现主库服务器 mysql2 查看二进制文件和同步点
show master status;
#在原主库服务器 mysql1 执行同步操作
change master to master_host='192.168.136.160',master_user='myslave',master_password='abc123',master_log_file='mysql-bin.000002',master_log_pos=154;
start slave;
(3)在 manager 节点上修改配置文件mysql_mha.cnf(再把这个记录添加进去,因为它检测掉失效时候会自动消失)
vim /opt/mysql-mha/mysql_mha.cnf
(4)在 manager 节点上启动 MHA
masterha_stop --conf=/opt/mysql-mha/mysql_mha.cnf #停止manager
nohup masterha_manager \
--conf=/opt/mysql-mha/mysql_mha.cnf \
--remove_dead_master_conf \
--ignore_last_failover < /dev/null > /var/log/mha_manager.log 2>&1 & #启动manager
#关闭主(备主)
systemctl stop mysqld
tail -f /opt/mysql-mha/manager.log