MHA：Master High Availability，对主节点进行监控，可实现自动故障转移至其它从节点；通过提升某一从节点为新的主节点，基于主从复制实现，还需要客户端配合实现，目前MHA主要支持一主
MHA：Master High Availability，对主节点进行监控，可实现自动故障转移至其它从节点；通过提升某一从节点为新的主节点，基于主从复制实现，还需要客户端配合实现，目前MHA主要支持一主多从的架构，要搭建MHA,要求一个复制集群中必须最少有三台数据库服务器，一主二从，即一台充当master，一台充当备用master，另外一台充当从库。
MHA工作原理：
MHA利用 SELECT 1 As Value 指令判断master服务器的健康性,一旦master 宕机,MHA 从宕机崩溃的master保存二进制日志事件（binlog events）
识别含有最新更新的slave
应用差异的中继日志（relay log）到其他的slave
应用从master保存的二进制日志事件（binlog events）
提升一个slave为新的master
使其他的slave连接新的master进行复制
MHA软件
MHA软件由两部分组成，Manager工具包和Node工具包
Manager工具包主要包括以下几个工具：
masterha_check_ssh
masterha_check_repl
masterha_manger
masterha_check_status
masterha_master_monitor
masterha_master_switch
masterha_conf_host
masterha_stop --conf=app1.cnf
masterha_secondary_check#检查MHA的SSH配置状况
#检查MySQL复制状况
#启动MHA
#检测当前MHA运行状态
#检测master是否宕机
#故障转移（自动或手动）
#添加或删除配置的server信息
#停止MHA
#两个或多个网络线路检查MySQL主服务器的可用Node工具包：
这些工具通常由MHA Manager的脚本触发，无需人为操作）主要包括以下几个工具：
save_binary_logs
apply_diff_relay_logs
filter_mysqlbinlog
purge_relay_logs#保存和复制master的二进制日志
#识别差异的中继日志事件并将其差异的事件应用于其他的slave
#去除不必要的ROLLBACK事件（MHA已不再使用此工具）
#清除中继日志（不会阻塞SQL线程）MHA自定义扩展：
secondary_check_script
master_ip_ailover_script
shutdown_script
report_script
init_conf_load_script
master_ip_online_change_script
#通过多条网络路由检测master的可用性
#更新Application使用的masterip
#强制关闭master节点
#发送报告
#加载初始配置参数
#更新master节点ip地址
MHA配置文件：
global配置，为各application提供默认配置，默认文件路径 /etc/masterha_default.cnf
application配置：为每个主从复制集群
实现MHA实战案例
环境：四台主机
10.0.0.7 CentOS7 MHA管理端
10.0.0.8 CentOS8 MySQL8.0 Master
10.0.0.18 CentOS8 MySQL8.0 Slave1
10.0.0.28 CentOS8 MySQL8.0 Slave2
1.在管理节点上安装两个包mha4mysql-manager和mha4mysql-node
说明：
mha4mysql-manager-0.56-0.el6.noarch.rpm 不支持CentOS 8，只支持CentOS7 以下版本
mha4mysql-manager-0.58-0.el7.centos.noarch.rpm 支持MySQL5.7和MySQL8.0 ,但和CentOS8版本上的Mariadb -10.3.17不兼容
两个安装包：
mha4mysql-manager
mha4mysql-node
管理端安装两个RPM包：
[root@MHA-Manager ~]# ll
total 144
-rw-------. 1 root root 1764 Apr 24 12:19 anaconda-ks.cfg
-rw-r--r-- 1 root root 0 Apr 28 11:20 a.txt
-rw-r--r-- 1 root root 587 May 12 21:13 CentOS-8.repo
-rw-r--r-- 1 root root 920 Apr 29 14:50 f1.txt
-rw-r--r-- 1 root root 1601 Apr 29 14:50 f2.txt
-rw-r--r-- 1 root root 1076 May 2 09:38 ks-centos8.cfg
-rw-r--r-- 1 root root 949 Apr 28 14:35 ks.cfg
-rw-r--r-- 1 root root 81024 Jul 30 2020 mha4mysql-manager-0.58-0.el7.centos.noarch.rpm
-rw-r--r-- 1 root root 36328 Jul 30 2020 mha4mysql-node-0.58-0.el7.centos.noarch.rpm
-rw-r--r-- 1 root root 41 Apr 27 08:50 test.sh
drwxr-xr-x. 2 root root 220 Apr 24 14:46 yum
#这里一定要先装mha4mysql-node，然后再装mha4mysql-manager
[root@MHA-Manager ~]# yum install -y mha4mysql-node-0.58-0.el7.centos.noarch.rpm
[root@MHA-Manager ~]# yum install -y mha4mysql-manager-0.58-0.el7.centos.noarch.rpm
2.在所有MySQL服务器上安装mha4mysql-node包
[root@Master ~]# yum install -y mha4mysql-node-0.58-0.el7.centos.noarch.rpm
[root@Slave1 ~]# yum install -y mha4mysql-node-0.58-0.el7.centos.noarch.rpm
[root@Slave2 ~]# yum install -y mha4mysql-node-0.58-0.el7.centos.noarch.rpm
3.在所有节点实现相互之间ssh key验证
[root@MHA-Manager ~]# ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):
Created directory '/root/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:C9ovIIe3BWcMBFTZgs0pi9ECVq7166py11oDCLgWfNM root@MHA-Manager.magedu.com
The key's randomart image is:
+---[RSA 2048]----+
|o++Oo+ |
|* = O . |
|o* B E |
|.o*.+ + |
|.o...=. S |
|. o ++o. . |
| +.*+ . |
|. . +.oo |
|.o.ooo .. |
+----[SHA256]-----+
[root@MHA-Manager ~]# ssh-copy-id 127.0.0.1
[root@MHA-Manager ~]# rsync -av .ssh 10.0.0.8:/root/
[root@MHA-Manager ~]# rsync -av .ssh 10.0.0.18:/root/
[root@MHA-Manager ~]# rsync -av .ssh 10.0.0.28:/root/
4.在管理节点建立配置文件
[root@MHA-Manager ~]# mkdir /etc/mastermha/
[root@MHA-Manager ~]# vim /etc/mastermha/app1.conf
[server default]
user=mhauser #用于远程连接MySQL所有节点的用户,需要有管理员的权限
password=magedu
manager_workdir=/data/mastermha/app1/ #目录会自动生成,无需手动创建
manager_log=/data/mastermha/app1/manager.log
remote_workdir=/data/mastermha/app1/
ssh_user=root #用于实现远程ssh基于KEY的连接,访问二进制日志
repl_user=repluser #主从复制的用户信息
repl_password=magedu
ping_interval=1 #健康性检查的时间间隔
master_ip_failover_script=/usr/local/bin/master_ip_failover #切换VIP的perl脚本
report_script=/usr/local/bin/sendmail.sh #当执行报警脚本
check_repl_delay=0 #默认值为1,表示如果slave中从库落后主库relay log超过100M，主库不会选择这个从库为新的master，因为这个从库进行恢复需要很长的时间.通过设置参数check_repl_delay=0，mha触发主从切换时会忽略复制的延时，对于设置candidate_master=1的从库非常有用，这样确保这个从库一定能成为最新的master
master_binlog_dir=/data/mysql/ #指定二进制日志存放的目录,mha4mysql-manager-0.58必须指定,之前版本不需要指定
[server1]
hostname=10.0.0.8
candidate_master=1
[server2]
hostname=10.0.0.18
candidate_master=1 #设置为优先候选master，即使不是集群中事件最新的slave,也会优先当master
[server3]
hostname=10.0.0.28
#最终文件内容
[root@MHA-Manager ~]# cat /etc/mastermha/app1.conf
[server default]
user=mhauser
password=magedu
manager_workdir=/data/mastermha/app1/
manager_log=/data/mastermha/app1/manager.log
remote_workdir=/data/mastermha/app1/
ssh_user=root
repl_user=repluser
repl_password=magedu
ping_interval=1
master_ip_failover_script=/usr/local/bin/master_ip_failover
report_script=/usr/local/bin/sendmail.sh
check_repl_delay=0
master_binlog_dir=/data/mysql/
[server1]
hostname=10.0.0.8
candidate_master=1
[server2]
hostname=10.0.0.18
candidate_master=1
[server3]
hostname=10.0.0.28
[root@MHA-Manager ~]#
说明：主库宕机谁来接管新的Master
1. 所有从节点日志都是一致的，默认会以配置文件的顺序去选择一个新主
2. 从节点日志不一致，自动选择最接近于主库的从库充当新主
3. 如果对于某节点设定了权重（candidate_master=1），权重节点会优先选择。但是此节点日志量落后主库超过100M日志的话，也不会被选择。可以配合check_repl_delay=0，关闭日志量的检查，强制选择候选节点
5.相关脚本
[root@MHA-Manager ~]# cat /usr/local/bin/sendmail.sh
#!/bin/bash
echo "MySQL is down" | mail -s "MHA Warning" 15762354477@139.com
[root@MHA-Manager ~]# chmod +x /usr/local/bin/sendmail.sh
[root@MHA-Manager ~]# vim /usr/local/bin/master_ip_failover
#!/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
);
#执行时必须删除下面三行注释
my $vip = '10.0.0.100/24';#设置Virtual IP
my $gateway = '10.0.0.254';#网关Gateway IP
my $interface = 'eth0';#指定VIP所在网卡
my $key = "1";
my $ssh_start_vip = "/sbin/ifconfig $interface:$key $vip;/sbin/arping -I $interface -c 3 -s $vip $gateway >/dev/null 2>&1";
my $ssh_stop_vip = "/sbin/ifconfig $interface:$key down";
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" ) {
# $orig_master_host, $orig_master_ip, $orig_master_port are passed.
# If you manage master ip address at global catalog database,
# invalidate orig_master_ip here.
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" ) {
# all arguments are passed.
# # If you manage master ip address at global catalog database,
# # activate new_master_ip here.
# # You can also grant write access (create user, set read_only=0, etc) here.
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";
`ssh $ssh_user\@$orig_master_host \" $ssh_start_vip \"`;
exit 0;
}
else {
&usage();
exit 1;
}
}
# A simple system call that enable the VIP on the new master
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";
}
#最终文件内容
[root@MHA-Manager ~]# cat /usr/local/bin/master_ip_failover
#!/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 = '10.0.0.100/24';
my $gateway = '10.0.0.254';
my $interface = 'eth0';
my $key = "1";
my $ssh_start_vip = "/sbin/ifconfig $interface:$key $vip;/sbin/arping -I $interface -c 3 -s $vip $gateway >/dev/null 2>&1";
my $ssh_stop_vip = "/sbin/ifconfig $interface:$key down";
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" ) {
# $orig_master_host, $orig_master_ip, $orig_master_port are passed.
# If you manage master ip address at global catalog database,
# invalidate orig_master_ip here.
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" ) {
# all arguments are passed.
# # If you manage master ip address at global catalog database,
# # activate new_master_ip here.
# # You can also grant write access (create user, set read_only=0, etc) here.
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";
`ssh $ssh_user\@$orig_master_host \" $ssh_start_vip \"`;
exit 0;
}
else {
&usage();
exit 1;
}
}
# A simple system call that enable the VIP on the new master
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@MHA-Manager ~]# chmod +x /usr/local/bin/master_ip_failover
[root@MHA-Manager ~]#
6.实现Master
[root@Master ~]# yum install -y mysql-server
[root@Master ~]# mkdir /data/mysql/
[root@Master ~]# chown mysql:mysql /data/mysql/
[root@Master ~]# vim /etc/my.cnf.d/mysql-server.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
log-error=/var/log/mysql/mysqld.log
pid-file=/run/mysqld/mysqld.pid
server-id=8
log-bin=/data/mysql/mysql-bin
skip_name_resolve=1
general_log #观察结果,非必须项,生产无需启用
[root@Master ~]# systemctl enable --now mysqld.service
[root@Master ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.21 Source distribution
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> show master logs;
+------------------+-----------+-----------+
| Log_name | File_size | Encrypted |
+------------------+-----------+-----------+
| mysql-bin.000001 | 179 | No |
| mysql-bin.000002 | 1201 | No |
+------------------+-----------+-----------+
2 rows in set (0.00 sec)
mysql> create user repluser@'10.0.0.%' identified by 'magedu';
Query OK, 0 rows affected (0.01 sec)
mysql> grant replication slave on *.* to repluser@'10.0.0.%' ;
Query OK, 0 rows affected (0.00 sec)
mysql> create user mhauser@'10.0.0.%' identified by 'magedu';
Query OK, 0 rows affected (0.01 sec)
mysql> grant all on *.* to mhauser@'10.0.0.%' ;
Query OK, 0 rows affected (0.01 sec)
mysql> select user,host from mysql.user;
+------------------+-----------+
| user | host |
+------------------+-----------+
| mhauser | 10.0.0.% |
| repluser | 10.0.0.% |
| mysql.infoschema | localhost |
| mysql.session | localhost |
| mysql.sys | localhost |
| root | localhost |
+------------------+-----------+
6 rows in set (0.00 sec)
mysql> quit
Bye
#配置VIP
[root@Master ~]# ifconfig eth0:1 10.0.0.100/24
[root@Master ~]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 10.0.0.8 netmask 255.255.255.0 broadcast 10.0.0.255
inet6 fe80::809c:7c3f:dc61:53bb prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:0a:08:a3 txqueuelen 1000 (Ethernet)
RX packets 67605 bytes 91484149 (87.2 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 31053 bytes 2925668 (2.7 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
eth0:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 10.0.0.100 netmask 255.255.255.0 broadcast 10.0.0.255
ether 00:0c:29:0a:08:a3 txqueuelen 1000 (Ethernet)
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
[root@Master ~]#
7.实现Slave
[root@Slave1 ~]# yum install -y mysql-server
[root@Slave1 ~]# mkdir /data/mysql/
[root@Slave1 ~]# chown mysql:mysql /data/mysql/
[root@Slave1 ~]# vim /etc/my.cnf.d/mysql-server.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
log-error=/var/log/mysql/mysqld.log
pid-file=/run/mysqld/mysqld.pid
server_id=18 #不同节点此值各不相同
log-bin=/data/mysql/mysql-bin
read_only
relay_log_purge=0
skip_name_resolve=1 #禁止反向解析
general_log #方便观察的设置,生产无需启用
[root@Slave1 ~]# systemctl enable --now mysqld.service
[root@Slave1 ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.21 Source distribution
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> CHANGE MASTER TO
-> MASTER_HOST='10.0.0.100',
-> MASTER_USER='repluser',
-> MASTER_PASSWORD='magedu',
-> MASTER_LOG_FILE='mysql-bin.000002',
-> MASTER_LOG_POS=1201;
Query OK, 0 rows affected, 2 warnings (0.05 sec)
mysql> start slave;
Query OK, 0 rows affected (0.01 sec)
mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 10.0.0.100
Master_User: repluser
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000002
Read_Master_Log_Pos: 1201
Relay_Log_File: Slave1-relay-bin.000002
Relay_Log_Pos: 324
Relay_Master_Log_File: mysql-bin.000002
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 1201
Relay_Log_Space: 534
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 8
Master_UUID: bb4f4671-baa2-11eb-8cf4-000c290a08a3
Master_Info_File: mysql.slave_master_info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
Master_public_key_path:
Get_master_public_key: 0
Network_Namespace:
1 row in set (0.00 sec)
mysql> quit
Bye
[root@Slave1 ~]#
[root@Slave2 ~]# yum install -y mysql-server
[root@Slave2 ~]# mkdir -p /data/mysql/
[root@Slave2 ~]# chown mysql:mysql /data/mysql/
[root@Slave2 ~]# vim /etc/my.cnf.d/mysql-server.cnf
[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
log-error=/var/log/mysql/mysqld.log
pid-file=/run/mysqld/mysqld.pid
server_id=28 #不同节点此值各不相同
log-bin=/data/mysql/mysql-bin
read_only
relay_log_purge=0
skip_name_resolve=1 #禁止反向解析
general_log #方便观察的设置,生产无需启用
[root@Slave2 ~]# systemctl enable --now mysqld.service
[root@Slave2 ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.21 Source distribution
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> CHANGE MASTER TO
-> MASTER_HOST='10.0.0.100',
-> MASTER_USER='repluser',
-> MASTER_PASSWORD='magedu',
-> MASTER_LOG_FILE='mysql-bin.000002',
-> MASTER_LOG_POS=1201;
Query OK, 0 rows affected, 2 warnings (0.03 sec)
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)
mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 10.0.0.100
Master_User: repluser
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000002
Read_Master_Log_Pos: 1201
Relay_Log_File: Slave2-relay-bin.000002
Relay_Log_Pos: 324
Relay_Master_Log_File: mysql-bin.000002
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 1201
Relay_Log_Space: 534
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 8
Master_UUID: bb4f4671-baa2-11eb-8cf4-000c290a08a3
Master_Info_File: mysql.slave_master_info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
Master_public_key_path:
Get_master_public_key: 0
Network_Namespace:
1 row in set (0.00 sec)
mysql> quit
Bye
[root@Slave2 ~]#
8.检查MHA的环境
[root@MHA-Manager ~]# masterha_check_ssh --conf=/etc/mastermha/app1.conf
Sat May 22 10:40:36 2021 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Sat May 22 10:40:36 2021 - [info] Reading application default configuration from /etc/mastermha/app1.conf..
Sat May 22 10:40:36 2021 - [info] Reading server configuration from /etc/mastermha/app1.conf..
Sat May 22 10:40:36 2021 - [info] Starting SSH connection tests..
Sat May 22 10:40:37 2021 - [debug]
Sat May 22 10:40:36 2021 - [debug] Connecting via SSH from root@10.0.0.8(10.0.0.8:22) to root@10.0.0.18(10.0.0.18:22)..
Sat May 22 10:40:36 2021 - [debug] ok.
Sat May 22 10:40:36 2021 - [debug] Connecting via SSH from root@10.0.0.8(10.0.0.8:22) to root@10.0.0.28(10.0.0.28:22)..
Warning: Permanently added '10.0.0.28' (ECDSA) to the list of known hosts.
Sat May 22 10:40:37 2021 - [debug] ok.
Sat May 22 10:40:37 2021 - [debug]
Sat May 22 10:40:36 2021 - [debug] Connecting via SSH from root@10.0.0.18(10.0.0.18:22) to root@10.0.0.8(10.0.0.8:22)..
Sat May 22 10:40:37 2021 - [debug] ok.
Sat May 22 10:40:37 2021 - [debug] Connecting via SSH from root@10.0.0.18(10.0.0.18:22) to root@10.0.0.28(10.0.0.28:22)..
Sat May 22 10:40:37 2021 - [debug] ok.
Sat May 22 10:40:38 2021 - [debug]
Sat May 22 10:40:37 2021 - [debug] Connecting via SSH from root@10.0.0.28(10.0.0.28:22) to root@10.0.0.8(10.0.0.8:22)..
Sat May 22 10:40:37 2021 - [debug] ok.
Sat May 22 10:40:37 2021 - [debug] Connecting via SSH from root@10.0.0.28(10.0.0.28:22) to root@10.0.0.18(10.0.0.18:22)..
Sat May 22 10:40:38 2021 - [debug] ok.
Sat May 22 10:40:38 2021 - [info] All SSH connection tests passed successfully.
[root@MHA-Manager ~]# masterha_check_repl --conf=/etc/mastermha/app1.conf
Sat May 22 10:43:06 2021 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Sat May 22 10:43:06 2021 - [info] Reading application default configuration from /etc/mastermha/app1.conf..
Sat May 22 10:43:06 2021 - [info] Reading server configuration from /etc/mastermha/app1.conf..
Sat May 22 10:43:06 2021 - [info] MHA::MasterMonitor version 0.58.
Creating directory /data/mastermha/app1/.. done.
Sat May 22 10:43:06 2021 - [error][/usr/share/perl5/vendor_perl/MHA/Server.pm, ln180] Got MySQL error when connecting 10.0.0.18(10.0.0.18:3306) :1130:Host '10.0.0.7' is not allowed to connect to this MySQL server, but this is not a MySQL crash. Check MySQL server settings.
Sat May 22 10:43:06 2021 - [error][/usr/share/perl5/vendor_perl/MHA/Server.pm, ln180] Got MySQL error when connecting 10.0.0.28(10.0.0.28:3306) :1130:Host '10.0.0.7' is not allowed to connect to this MySQL server, but this is not a MySQL crash. Check MySQL server settings.
Sat May 22 10:43:06 2021 - [error][/usr/share/perl5/vendor_perl/MHA/ServerManager.pm, ln301] at /usr/share/perl5/vendor_perl/MHA/ServerManager.pm line 297.
Sat May 22 10:43:06 2021 - [error][/usr/share/perl5/vendor_perl/MHA/ServerManager.pm, ln301] at /usr/share/perl5/vendor_perl/MHA/ServerManager.pm line 297.
Sat May 22 10:43:07 2021 - [error][/usr/share/perl5/vendor_perl/MHA/ServerManager.pm, ln309] Got fatal error, stopping operations
Sat May 22 10:43:07 2021 - [error][/usr/share/perl5/vendor_perl/MHA/MasterMonitor.pm, ln427] Error happened on checking configurations. at /usr/share/perl5/vendor_perl/MHA/MasterMonitor.pm line 329.
Sat May 22 10:43:07 2021 - [error][/usr/share/perl5/vendor_perl/MHA/MasterMonitor.pm, ln525] Error happened on monitoring servers.
Sat May 22 10:43:07 2021 - [info] Got exit code 1 (Not master dead).
MySQL Replication Health is NOT OK!
#这里Slave从节点的健康性检查失败是因为Slave从节点的数据库中不存在repluser和mhauser用户，造成管理节点连不到两个从节点服务器，那么这里我在两个从节点上创建这两个账户用户并进行授权
[root@Slave1 ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 12
Server version: 8.0.21 Source distribution
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> create user repluser@'10.0.0.%' identified by 'magedu';
Query OK, 0 rows affected (0.01 sec)
mysql> grant replication slave on *.* to repluser@'10.0.0.%' ;
Query OK, 0 rows affected (0.00 sec)
mysql> create user mhauser@'10.0.0.%' identified by 'magedu';
Query OK, 0 rows affected (0.01 sec)
mysql> grant all on *.* to mhauser@'10.0.0.%' ;
Query OK, 0 rows affected (0.00 sec)
mysql> select user,host from mysql.user;
+------------------+-----------+
| user | host |
+------------------+-----------+
| mhauser | 10.0.0.% |
| repluser | 10.0.0.% |
| mysql.infoschema | localhost |
| mysql.session | localhost |
| mysql.sys | localhost |
| root | localhost |
+------------------+-----------+
6 rows in set (0.00 sec)
mysql> quit
Bye
[root@Slave2 ~]# mysql
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 12
Server version: 8.0.21 Source distribution
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> create user repluser@'10.0.0.%' identified by 'magedu';
Query OK, 0 rows affected (0.01 sec)
mysql> grant replication slave on *.* to repluser@'10.0.0.%' ;
Query OK, 0 rows affected (0.00 sec)
mysql> create user mhauser@'10.0.0.%' identified by 'magedu';
Query OK, 0 rows affected (0.01 sec)
mysql> grant all on *.* to mhauser@'10.0.0.%' ;
Query OK, 0 rows affected (0.00 sec)
mysql> select user,host from mysql.user;
+------------------+-----------+
| user | host |
+------------------+-----------+
| mhauser | 10.0.0.% |
| repluser | 10.0.0.% |
| mysql.infoschema | localhost |
| mysql.session | localhost |
| mysql.sys | localhost |
| root | localhost |
+------------------+-----------+
6 rows in set (0.00 sec)
mysql> quit
Bye
#重新检查环境，检查正常
[root@MHA-Manager ~]# masterha_check_repl --conf=/etc/mastermha/app1.conf
Sat May 22 15:42:57 2021 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Sat May 22 15:42:57 2021 - [info] Reading application default configuration from /etc/mastermha/app1.conf..
Sat May 22 15:42:57 2021 - [info] Reading server configuration from /etc/mastermha/app1.conf..
Sat May 22 15:42:57 2021 - [info] MHA::MasterMonitor version 0.58.
Sat May 22 15:42:58 2021 - [info] GTID failover mode = 0
Sat May 22 15:42:58 2021 - [info] Dead Servers:
Sat May 22 15:42:58 2021 - [info] Alive Servers:
Sat May 22 15:42:58 2021 - [info] 10.0.0.8(10.0.0.8:3306)
Sat May 22 15:42:58 2021 - [info] 10.0.0.18(10.0.0.18:3306)
Sat May 22 15:42:58 2021 - [info] 10.0.0.28(10.0.0.28:3306)
Sat May 22 15:42:58 2021 - [info] Alive Slaves:
Sat May 22 15:42:58 2021 - [info] 10.0.0.18(10.0.0.18:3306) Version=8.0.21 (oldest major version between slaves) log-bin:enabled
Sat May 22 15:42:58 2021 - [info] Replicating from 10.0.0.8(10.0.0.8:3306)
Sat May 22 15:42:58 2021 - [info] Primary candidate for the new Master (candidate_master is set)
Sat May 22 15:42:58 2021 - [info] 10.0.0.28(10.0.0.28:3306) Version=8.0.21 (oldest major version between slaves) log-bin:enabled
Sat May 22 15:42:58 2021 - [info] Replicating from 10.0.0.8(10.0.0.8:3306)
Sat May 22 15:42:58 2021 - [info] Current Alive Master: 10.0.0.8(10.0.0.8:3306)
Sat May 22 15:42:58 2021 - [info] Checking slave configurations..
Sat May 22 15:42:58 2021 - [info] Checking replication filtering settings..
Sat May 22 15:42:58 2021 - [info] binlog_do_db= , binlog_ignore_db=
Sat May 22 15:42:58 2021 - [info] Replication filtering check ok.
Sat May 22 15:42:58 2021 - [info] GTID (with auto-pos) is not supported
Sat May 22 15:42:58 2021 - [info] Starting SSH connection tests..
Sat May 22 15:43:00 2021 - [info] All SSH connection tests passed successfully.
Sat May 22 15:43:00 2021 - [info] Checking MHA Node version..
Sat May 22 15:43:01 2021 - [info] Version check ok.
Sat May 22 15:43:01 2021 - [info] Checking SSH publickey authentication settings on the current master..
Sat May 22 15:43:01 2021 - [info] HealthCheck: SSH to 10.0.0.8 is reachable.
Sat May 22 15:43:01 2021 - [info] Master MHA Node version is 0.58.
Sat May 22 15:43:01 2021 - [info] Checking recovery script configurations on 10.0.0.8(10.0.0.8:3306)..
Sat May 22 15:43:01 2021 - [info] Executing command: save_binary_logs --command=test --start_pos=4 --binlog_dir=/data/mysql/ --output_file=/data/mastermha/app1//save_binary_logs_test --manager_version=0.58 --start_file=mysql-bin.000007
Sat May 22 15:43:01 2021 - [info] Connecting to root@10.0.0.8(10.0.0.8:22)..
Creating /data/mastermha/app1 if not exists.. ok.
Checking output directory is accessible or not..
ok.
Binlog found at /data/mysql/, up to mysql-bin.000007
Sat May 22 15:43:01 2021 - [info] Binlog setting check done.
Sat May 22 15:43:01 2021 - [info] Checking SSH publickey authentication and checking recovery script configurations on all alive slave servers..
Sat May 22 15:43:01 2021 - [info] Executing command : apply_diff_relay_logs --command=test --slave_user='mhauser' --slave_host=10.0.0.18 --slave_ip=10.0.0.18 --slave_port=3306 --workdir=/data/mastermha/app1/ --target_version=8.0.21 --manager_version=0.58 --relay_dir=/var/lib/mysql --current_relay_log=Slave1-relay-bin.000008 --slave_pass=xxx
Sat May 22 15:43:01 2021 - [info] Connecting to root@10.0.0.18(10.0.0.18:22)..
Checking slave recovery environment settings..
Relay log found at /var/lib/mysql, up to Slave1-relay-bin.000008
Temporary relay log file is /var/lib/mysql/Slave1-relay-bin.000008
Checking if super_read_only is defined and turned on.. not present or turned off, ignoring.
Testing mysql connection and privileges..
mysql: [Warning] Using a password on the command line interface can be insecure.
done.
Testing mysqlbinlog output.. done.
Cleaning up test file(s).. done.
Sat May 22 15:43:02 2021 - [info] Executing command : apply_diff_relay_logs --command=test --slave_user='mhauser' --slave_host=10.0.0.28 --slave_ip=10.0.0.28 --slave_port=3306 --workdir=/data/mastermha/app1/ --target_version=8.0.21 --manager_version=0.58 --relay_dir=/var/lib/mysql --current_relay_log=Slave2-relay-bin.000010 --slave_pass=xxx
Sat May 22 15:43:02 2021 - [info] Connecting to root@10.0.0.28(10.0.0.28:22)..
Checking slave recovery environment settings..
Relay log found at /var/lib/mysql, up to Slave2-relay-bin.000010
Temporary relay log file is /var/lib/mysql/Slave2-relay-bin.000010
Checking if super_read_only is defined and turned on.. not present or turned off, ignoring.
Testing mysql connection and privileges..
mysql: [Warning] Using a password on the command line interface can be insecure.
done.
Testing mysqlbinlog output.. done.
Cleaning up test file(s).. done.
Sat May 22 15:43:02 2021 - [info] Slaves settings check done.
Sat May 22 15:43:02 2021 - [info]
10.0.0.8(10.0.0.8:3306) (current master)
+--10.0.0.18(10.0.0.18:3306)
+--10.0.0.28(10.0.0.28:3306)
Sat May 22 15:43:02 2021 - [info] Checking replication health on 10.0.0.18..
Sat May 22 15:43:02 2021 - [info] ok.
Sat May 22 15:43:02 2021 - [info] Checking replication health on 10.0.0.28..
Sat May 22 15:43:02 2021 - [info] ok.
Sat May 22 15:43:02 2021 - [info] Checking master_ip_failover_script status:
Sat May 22 15:43:02 2021 - [info] /usr/local/bin/master_ip_failover --command=status --ssh_user=root --orig_master_host=10.0.0.8 --orig_master_ip=10.0.0.8 --orig_master_port=3306
IN SCRIPT TEST====/sbin/ifconfig eth0:1 down==/sbin/ifconfig eth0:1 10.0.0.100/24;/sbin/arping -I eth0 -c 3 -s 10.0.0.100/24 10.0.0.254 >/dev/null 2>&1===
Checking the Status of the script.. OK
Sat May 22 15:43:03 2021 - [info] OK.
Sat May 22 15:43:03 2021 - [warning] shutdown_script is not defined.
Sat May 22 15:43:03 2021 - [info] Got exit code 0 (Not master dead).
MySQL Replication Health is OK.
[root@MHA-Manager ~]#
9.启动MHA
开启MHA,默认是前台运行,生产环境一般为后台执行
[root@MHA-Manager ~]# nohup masterha_manager --conf=/etc/mastermha/app1.conf &> /dev/null
查看状态
[root@MHA-Manager ~]# masterha_check_status --conf=/etc/mastermha/app1.conf
app1 (pid:1321) is running(0:PING_OK), master:10.0.0.8
在Master服务器上进行健康性检查
[root@Master ~]# tail -f /var/lib/mysql/Master.log
2021-05-22T08:08:15.494093Z 24 QuerySELECT 1 As Value
2021-05-22T08:08:16.494128Z 24 QuerySELECT 1 As Value
2021-05-22T08:08:17.496217Z 24 QuerySELECT 1 As Value
2021-05-22T08:08:18.498052Z 24 QuerySELECT 1 As Value
2021-05-22T08:08:19.500948Z 24 QuerySELECT 1 As Value
2021-05-22T08:08:20.504335Z 24 QuerySELECT 1 As Value
2021-05-22T08:08:21.507257Z 24 QuerySELECT 1 As Value
2021-05-22T08:08:22.507209Z 24 QuerySELECT 1 As Value
2021-05-22T08:08:23.507075Z 24 QuerySELECT 1 As Value
2021-05-22T08:08:24.509524Z 24 QuerySELECT 1 As Value
2021-05-22T08:08:25.510962Z 24 QuerySELECT 1 As Value
2021-05-22T08:08:26.511363Z 24 QuerySELECT 1 As Value
2021-05-22T08:08:27.513529Z 24 QuerySELECT 1 As Value
10.模拟故障
停掉Master服务器的MySQL服务
[root@Master ~]# systemctl stop mysqld.service
查看状态
[root@MHA-Manager ~]# masterha_check_status --conf=/etc/mastermha/app1.conf
app1 is stopped(2:NOT_RUNNING).
验证VIP漂移至新的Master上
[root@Slave1 ~]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 10.0.0.18 netmask 255.255.255.0 broadcast 10.0.0.255
inet6 fe80::5a87:1464:beb7:38 prefixlen 64 scopeid 0x20<link>
ether 00:0c:29:9d:3e:68 txqueuelen 1000 (Ethernet)
RX packets 70084 bytes 88687133 (84.5 MiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 35950 bytes 3857649 (3.6 MiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
eth0:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 10.0.0.100 netmask 255.255.255.0 broadcast 10.0.0.255
ether 00:0c:29:9d:3e:68 txqueuelen 1000 (Ethernet)
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10<host>
loop txqueuelen 1000 (Local Loopback)
RX packets 920 bytes 136130 (132.9 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 920 bytes 136130 (132.9 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
[root@Slave1 ~]#
文章写得有不恰当之处，请多见谅。
