Mysql的MHA高可用及故障切换

MHA

master high availability
建立在主从复制基础之上的故障切换的软件系统。

主从复制的单点问题

当主从复制当中，主服务器发生故障，会自动切换到一台从服务器，然后把从服务器升格为主，继续主从的架构

1. master开启二进制日志，并允许从节点复制主节点的二进制日志的内容

2. 通过vip地址，当主容机之后，vip会自动的飘移到从节点。

3. 从节点升级为主服务器，然后从宕机的master保存二进制日志，将更新的内容同步到新主，然后再同步到从节点。

配置

mysql1 192.168.246.6 主
mysql2 192.168.246.7 从1----主备
mysql3 192.168.246.10 从2
manager节点：u3 192.168.246.9 MHA的组件
vip 192.168.246.100

1. 主从复制

ntpdate ntp.aliyun.com
#时间同步vim /etc/my.cnf#主
log-bin=master-bin
binlog_format=MIXED
log-slave-updates=true
relay_log_recovery=1
#启用从库崩溃或者重启时，会自动尝试从日志当中恢复。#从1
server-id = 2
log-bin=master-bin
relay-log=relay-log-bin
relay-log-index=slave-relay-bin.index
relay_log_recovery = 1#从2
server-id = 3
relay-log=relay-log-bin
relay-log-index=slave-relay-bin.index
relay_log_recovery = 1#主从
mysql -u root -p123456#从数据库同步使用
CREATE USER 'myslave'@'192.168.246.%' IDENTIFIED WITH mysql_native_password BY '123456';
GRANT REPLICATION SLAVE ON *.* TO 'myslave'@'192.168.246.%';			#manager 使用
CREATE USER 'mha'@'192.168.246.%' IDENTIFIED WITH mysql_native_password BY 'manager';
GRANT ALL PRIVILEGES ON *.* TO 'mha'@'192.168.246.%' WITH GRANT OPTION;#防止从库通过主机名连接不上主库
CREATE USER 'mha'@'master' IDENTIFIED WITH mysql_native_password BY 'manager';
GRANT ALL PRIVILEGES ON *.* TO 'mha'@'master';
CREATE USER 'mha'@'slave1' IDENTIFIED WITH mysql_native_password BY 'manager';
GRANT ALL PRIVILEGES ON *.* TO 'mha'@'slave1';
CREATE USER 'mha'@'slave2' IDENTIFIED WITH mysql_native_password BY 'manager';
GRANT ALL PRIVILEGES ON *.* TO 'mha'@'slave2';flush privileges;#主
show master status;

#从1 从2
mysql -u root -p123456#同步建立
CHANGE master to master_host='192.168.246.6',master_user='myslave',master_password='123456',master_log_file='master-bin.000001',master_log_pos=157;start slave;show slave status\G;

#从库必须全部设置为只读模式
set global read_only=1;

2. MHA高可用

安装MHA的组件

• NODE ：监控每台机器上mysql的状态，传回给manager
• MANAGER：管理节点，控制mha的状态。

#每个服务器都需要安装MHA依赖的环境
apt install -y libdbd-mysql-perl \
libconfig-tiny-perl \
liblog-dispatch-perl \
libparallel-forkmanager-perl \
libextutils-cbuilder-perl \
libmodule-install-perl \
make#在MHA的manager节点上安装manager组件
cd /opt
tar -xf mha4mysql-manager-0.57.tar.gzcd mha4mysql-manager-0.57
perl Makefile.PL
make && make install

cd /opt
tar -xf mha4mysql-node-0.57.tar.gzcd mha4mysql-node-0.57
perl Makefile.PL
make && make install

#组件安装后在/usr/local/bin 下面会生成几个工具
masterha_check_ssh : 检查mha节点之间ssh的配置和通信
masterha_manager： manager的启动脚本
masterha_check_status： 检查mha的运行状态
masterha_stop：关闭manager
masterha_master_switch: 控制故障转移的方式
ave_binary_logs： 检查，保存，复制master节点的二进制日志
apply_diff_relay_logs： 识别二进制日志当中的差异部分，把差异的部分同步到slave

配置无密码认证

#配置所有节点之间的MHA的ssh的通信
#manager节点
ssh-keygen -t rsa
回车
ssh-copy-id 192.168.246.6
ssh-copy-id 192.168.246.7
ssh-copy-id 192.168.246.10#主
ssh-keygen -t rsa
回车
ssh-copy-id 192.168.246.7
ssh-copy-id 192.168.246.10#从
ssh-keygen -t rsa
回车
ssh-copy-id 192.168.246.6
ssh-copy-id 192.168.246.10

manager节点配置

root@u3:/usr/local/bin# cd /opt/mha4mysql-manager-0.57/samples/root@u3:/opt/mha4mysql-manager-0.57/samples# cp -rp /opt/mha4mysql-manager-0.57/samples/scripts  /usr/local/binroot@u3:/opt/mha4mysql-manager-0.57/samples# cp /usr/local/bin/scripts/master_ip_failover /usr/local/bin/root@u3:/opt/mha4mysql-manager-0.57/samples# vim /usr/local/bin/master_ip_failover
#删除全部，复制以下代码

#!/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 = '192.168.233.100';
my $brdc = '192.168.233.255';
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 $exit_code = 0;
GetOptions(
'command=s' => \$command,
'ssh_user=s' => \$ssh_user,
'orig_master_host=s' => \$orig_master_host,
'orig_master_ip=s' => \$orig_master_ip,
'orig_master_port=i' => \$orig_master_port,
'new_master_host=s' => \$new_master_host,
'new_master_ip=s' => \$new_master_ip,
'new_master_port=i' => \$new_master_port,
);exit &main();sub main {
print "\n\nIN SCRIPT TEST====$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";
}

root@u3:/opt/mha4mysql-manager-0.57/samples# mkdir /etc/masterharoot@u3:/opt/mha4mysql-manager-0.57/samples# ls
conf  scripts
root@u3:/opt/mha4mysql-manager-0.57/samples# cd conf/
root@u3:/opt/mha4mysql-manager-0.57/samples/conf# ls
app1.cnf  masterha_default.cnfroot@u3:/opt/mha4mysql-manager-0.57/samples/conf# cp /opt/mha4mysql-manager-0.57/samples/conf/app1.cnf /etc/masterha/
root@u3:/opt/mha4mysql-manager-0.57/samples/conf# vim /etc/masterha/app1.cnf
#复制以下代码，需要清除注释

[server default]
manager_log=/var/log/masterha/app1/manager.log
manager_workdir=/var/log/masterha/app1
master_binlog_dir=/usr/local/mysql/data
#指向到myql的默认位置master_ip_failover_script=/usr/local/bin/master_ip_failover
#切换vip的脚本master_ip_online_change_script=/usr/local/bin/master_ip_online_change
password=manager
ping_interval=1
#每一秒检测一次主的状态remote_workdir=/tmp
repl_password=123456
repl_user=myslave
secondary_check_script=/usr/local/bin/masterha_secondary_check -s 192.168.246.7 -s 192.168.246.10 
#从对主监听
shutdown_script=""
ssh_user=root
user=mha[server1]
hostname=192.168.246.6 
#主服务器port=3306[server2]
candidate_master=1   
#声明server2备服务器check_repl_delay=0
#立刻切换hostname=192.168.246.7
#备用主服务器
port=3306[server3]
hostname=192.168.246.10  
#从服务器2
port=3306

root@u3:/opt/mha4mysql-manager-0.57/samples/conf# vim /usr/local/share/perl/5.34.0/MHA/NodeUtil.pm#192行修改添加$str =~ /(\d+)\.(\d+)/;my $strmajor = "$1.$2";my $result = sprintf( '%03d%03d', $1, $2 ) if $str =~ m/(\d+)\.(\d+)/;

#主需要手动开启虚拟IP
ifconfig ens33:1 192.168.246.100/24#主从设置软连接
ln -s /usr/local/mysql/bin/mysql /usr/sbin/
ln -s /usr/local/mysql/bin/mysqlbinlog /usr/sbin/

manager节点上测试

#测试ssh无密码认证，如果正常最后会输出为successfully
masterha_check_ssh -conf=/etc/masterha/app1.cnf

＃测试mysql主从连接情况，最后出现is OK字样则正常。
masterha_check_repl -conf=/etc/masterha/app1.cnf

启动连接

#manager节点上
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 &
#nohup:执行记录，把执行记录保存到指定的文件。#检查master节点
root@u3:~# masterha_check_status --conf=/etc/masterha/app1.cnf
app1 (pid:4171) is running(0:PING_OK), master:192.168.246.6

#客户端
apt -y install mariadb-server#用vip连接
mysql -h 192.168.246.100 -u root -p123456MySQL [(none)]> create database test1;
Query OK, 1 row affected (0.139 sec)MySQL [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
| test1              |
+--------------------+
5 rows in set (0.004 sec)

故障切换模拟

#manager节点打开日志
tail -f /var/log/masterha/app1/manager.log#停止mha
master_stop --conf=/etc/masterha/appl.cnf#主
systemctl stop mysqld
#从1
ip addr

恢复

#manager节点
vim /etc/masterha/app1.cnf

原来的主自动删除了
修改并添加如下图的内容

#原来的主
vim /etc/my.cnflog-bin=master-bin
binlog_format=MIXED
relay-log=relay-log-bin
relay-log-index=slave-relay-bin.index
relay_log_recovery=1systemctl restart mysqld#从1
server-id = 2
log-bin=master-bin
log-slave-updates=true
relay-log=relay-log-bin
relay-log-index=slave-relay-bin.index
relay_log_recovery = 1mysql -u root -p123456
show master status;

原主与从2
CHANGE master to master_host='192.168.246.7',master_user='myslave',master_password='123456',master_log_file='master-bin.000001',master_log_pos=352;start slave;show slave status\G;

#客户端
root@u4:~# mysql -h 192.168.246.100 -u root -p123456
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MySQL connection id is 17
Server version: 8.0.30 MySQL Community Server - GPLCopyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.MySQL [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
| test1              |
+--------------------+
5 rows in set (0.004 sec)
4 rows in set (0.013 sec)MySQL [(none)]> create database test2;
Query OK, 1 row affected (0.139 sec)MySQL [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
| test1              |
+--------------------+
5 rows in set (0.004 sec)