Java学习笔记分享之MySQL篇

MySQL安装

问题汇总

Q1：登陆提示Access denied for user ‘root’@‘localhost’ (using password: YES)

在配置文件my.cnf/my.ini添加配置skip-grant-tables，跳过权限校验。
修改密码UPDATE mysql.user SET authentication_string = “*81F5E21E35407D884A6CD4A731AEBFB6AF209E1B”,password_expired=“N” WHERE User=“root” and Host=“localhost”;

Q2：主备同步的时候，由于Master执行的数据在Master中不存在或者异常通信导致数据不一致，MHA检测主从状态出现以下问题：Could not execute Update_rows event on table oa.bui_bill_sum; Can’t find record in ‘bui_bill_sum’, Error_code: 1032; handler error HA_ERR_KEY_NOT_FOUND; the event’s master log mysql-bin.000138, end_log_pos 160051747

# 在Slave中执行以下SQL,需要登陆到Mysql
STOP SLAVE;
SET GLOBAL sql_slave_skip_counter =1; #表示跳过一步错误，后面的数字可变
START SLAVE;

环境说明

Linux CentOS7服务器
MySQL 5.7 RPM mysql-5.7.28-1.el7.x86_64.rpm-bundle.tar
防火墙关闭

CentOS 6 处理方法

//临时关闭
service iptables stop
//禁止开机启动
chkconfig iptables off

CentOS 7 处理方法

CentOS 7版本以后防火墙默认使用firewalld，所以CentOS 7 防火墙命令和CentOS 6 存在差异。

//临时关闭
systemctl stop firewalld
//禁止开机启动
systemctl disable firewalld.service
Removed symlink /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.

如果安装了iptables-service选择方案

//安装ip服务
yum install -y iptables-services
//关闭防火墙
service iptables stop
Redirecting to /bin/systemctl stop  iptables.service
//检查防火墙状态
service iptables status
Redirecting to /bin/systemctl status  iptables.service
iptables.service - IPv4 firewall with iptablesLoaded: loaded (/usr/lib/systemd/system/iptables.service; disabled; vendor preset: disabled)Active: inactive (dead)

MySQL RPM安装

检查是否已经安装过MySQL

rpm -qa | grep mysql  # 如果没有打印就是没有安装
# 如果安装过了，那么可以卸载系统自带的
rpm -e mysql # 普通删除模式
rpm -e --nodeps mysql # 强力删除模式，如果使用上面的删除提示有其他依赖文件的时候，使用该命令可以强力删除

检查CentOS 7是否默认自带mariadb

# 检查mariadb是否安装
rpm -aq | grep mariadb
# 如果安装过，会显示如下
mariadb-libs-5.5.60-1.el7_5.x86_64
# 卸载 --nodeps参数作用是如果有依赖，会强力删除，如果不加可能会提示失败
rpm -e --nodeps mariadb-libs-5.5.60-1.el7_5.x86_64

上传RPM包

# 这里使用rz上传文件，如果没有安装这个命令可以使用以下命令安装，也可以使用Xftp客户端工具上传
yum install lrzsz
# 上传文件
rz # 打开文件夹选择窗口，上传文件到用户的home目录

解压RPM

tar -xvf mysql-5.7.28-1.el7.x86_64.rpm-bundle.tar
# 解压之后可以看到有多个RPM安装包
-rw-------. 1 root root       1455 10月  2 01:00 anaconda-ks.cfg
-rw-r--r--. 1 root root  609556480 9月  16 09:49 mysql-5.7.28-1.el7.x86_64.rpm-bundle.tar
-rw-r--r--. 1 7155 31415  45109364 9月  30 2019 mysql-community-client-5.7.28-1.el7.x86_64.rpm
-rw-r--r--. 1 7155 31415    318768 9月  30 2019 mysql-community-common-5.7.28-1.el7.x86_64.rpm
-rw-r--r--. 1 7155 31415   7037096 9月  30 2019 mysql-community-devel-5.7.28-1.el7.x86_64.rpm
-rw-r--r--. 1 7155 31415  49329100 9月  30 2019 mysql-community-embedded-5.7.28-1.el7.x86_64.rpm
-rw-r--r--. 1 7155 31415  23354908 9月  30 2019 mysql-community-embedded-compat-5.7.28-1.el7.x86_64.rpm
-rw-r--r--. 1 7155 31415 136837816 9月  30 2019 mysql-community-embedded-devel-5.7.28-1.el7.x86_64.rpm
-rw-r--r--. 1 7155 31415   4374364 9月  30 2019 mysql-community-libs-5.7.28-1.el7.x86_64.rpm
-rw-r--r--. 1 7155 31415   1353312 9月  30 2019 mysql-community-libs-compat-5.7.28-1.el7.x86_64.rpm
-rw-r--r--. 1 7155 31415 208694824 9月  30 2019 mysql-community-server-5.7.28-1.el7.x86_64.rpm
-rw-r--r--. 1 7155 31415 133129992 9月  30 2019 mysql-community-test-5.7.28-1.el7.x86_64.rpm

安装RPM

# 安装命令
rpm -ivh mysql-community-common-5.7.28-1.el7.x86_64.rpm
rpm -ivh mysql-community-libs-5.7.28-1.el7.x86_64.rpm
rpm -ivh mysql-community-libs-compat-5.7.28-1.el7.x86_64.rpm
rpm -ivh mysql-community-client-5.7.28-1.el7.x86_64.rpm
rpm -ivh mysql-community-server-5.7.28-1.el7.x86_64.rpm
rpm -ivh mysql-community-devel-5.7.28-1.el7.x86_64.rpm

MySQL的RPM安装需要注意依赖关系，不是随便安装就可以的。RPM的安装顺序如下：

mysql-community-common-5.7.28-1.el7.x86_64.rpm
mysql-community-libs-5.7.28-1.el7.x86_64.rpm
mysql-community-libs-compat-5.7.28-1.el7.x86_64.rpm (安装完这三个，其他的可以随意顺序安装)
mysql-community-client-5.7.28-1.el7.x86_64.rpm
mysql-community-server-5.7.28-1.el7.x86_64.rpm
mysql-community-devel-5.7.28-1.el7.x86_64.rpm（开发工具）

初始化数据库实例

mysqld --initialize --user=mysql

初始化数据库后，MySQL会创建一个root用户，但是密码是随机生成的，需要查看密码

cat /var/log/mysqld.log
# 显示结果如下  PkoI(_uFw3&t就是密码
2020-10-02T16:49:58.823691Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2020-10-02T16:49:59.143270Z 0 [Warning] InnoDB: New log files created, LSN=45790
2020-10-02T16:49:59.207287Z 0 [Warning] InnoDB: Creating foreign key constraint system tables.
2020-10-02T16:49:59.338916Z 0 [Warning] No existing UUID has been found, so we assume that this is the first time that this server has been started. Generating a new UUID: 4ee64a7b-04cf-11eb-b5d0-000c29fb7e1e.
2020-10-02T16:49:59.342706Z 0 [Warning] Gtid table is not ready to be used. Table 'mysql.gtid_executed' cannot be opened.
2020-10-02T16:49:59.827830Z 0 [Warning] CA certificate ca.pem is self signed.
2020-10-02T16:50:00.286400Z 1 [Note] A temporary password is generated for root@localhost: PkoI(_uFw3&t

MySQL启动

# 将MySQL作为服务注册到系统，跟随系统启动
systemctl start mysqld.service
# 查看状态
systemctl status mysqld.service
# 结果如下
mysqld.service - MySQL ServerLoaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)Active: active (running) since 六 2020-10-03 01:06:22 CST; 15s agoDocs: man:mysqld(8)http://dev.mysql.com/doc/refman/en/using-systemd.htmlProcess: 37965 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid $MYSQLD_OPTS (code=exited, status=0/SUCCESS)Process: 37948 ExecStartPre=/usr/bin/mysqld_pre_systemd (code=exited, status=0/SUCCESS)Main PID: 37969 (mysqld)CGroup: /system.slice/mysqld.service└─37969 /usr/sbin/mysqld --daemonize --pid-file=/var/run/mysqld/mysqld.pid10月 03 01:06:21 localhost.localdomain systemd[1]: Starting MySQL Server...
10月 03 01:06:22 localhost.localdomain systemd[1]: Started MySQL Server.

登陆MySQL

mysql -uroot -p
# 重新设置root密码
set password=password('root');
# 推出
exit
# 重新登陆检查密码是否正确
mysql -uroot -p

MySQL集群之主从复制

Master配置

配置文件为 /etc/my.cnf

# 基础配置只需要log_bin和server-id参数
log_bin=mysql-bin # 开启binlog
server-id=1 # 同一个集群要唯一
sync-binlog=1 # 每次执行都与磁盘同步
# 忽略某些数据库不需要同步
binlog-ignore-db=performance_schema
binlog-ignore-db=information_schema
binlog-ignore-db=sys
# 指定某些数据库需要同步
binlog-do-db=lagou

重启Mysql systemctl restart mysqld;

登陆主库授权从库复制操作

# 对从库的用户授权
grant replication slave on *.* to 'root'@'%' identified by 'root';
grant all privileges on *.* to 'root'@'*' identified by 'root';
# 刷新权限
flush privileges;
# 查看主库状态：
show master status;

Slave配置

# 登陆mysql 查看slave状态，如果开启需要停止 stop slave;
show slave status;
start slave;
stop slave;

配置文件为 /etc/my.cnf

# 从库读取主库binlog，所以从库binlog可以不开启
server-id=2
# 指定主机日志名称/权限等
relay_log=mysql-relay-bin
read_only=1

重启Mysql systemctl restart mysqld;

登陆mysql同步初始化命令,mysql环境下

# 从库从那个主库的那个日志文件的那个位置开始同步；
# master_log_file同步的日志文件
# master_log_pos同步开始的位置
change master to master_host='192.168.247.120',master_port=3306,master_user='root',master_password='root',master_log_file='mysql-bin.000002',master_log_pos=869;

# 开启slave
start slave;

MySQL集群之半同步复制

主库和从库的插件安装

# 登陆数据库后执行，查看是否支持插件的安装
select @@have_dynamic_loading;
# 查看已经安装了那些插件，如果没有semi就动态安装
show plugins;

安装semi插件

# master安装 soname是给插件一个名称
install plugin rpl_semi_sync_master soname 'semisync_master.so';
# 查看半同步复制相关的参数，默认没有开启，相关参数需要设置
show variables like '%semi%';
set global rpl_semi_sync_master_enabled=1; # 开启
set global rpl_semi_sync_master_timeout=1000; # 超时时间1秒# slave安装 soname是给插件一个名称
install plugin rpl_semi_sync_slave soname 'semisync_slave.so';
# 查看半同步复制相关的参数，默认没有开启，相关参数需要设置
show variables like '%semi%';
set global rpl_semi_sync_slave_enabled=1; # 开启
# 重启slave
stop slave;
start slave;

查看是否使用半同步复制

# 在Master端查看日志
cat /var/log/mysqld.log
# 如果看到以下信息：
semi-sync等就是使用了半同步

MySQL集群之并行复制

并行复制主要是通过MySQL的配置开启

MySQL 5.6并行复制

暂无

MySQL 5.7 并行复制

# Master的并行复制参数
show variables like '%binlog_group%';
# 组同步提交延迟
set global binlog_group_commit_sync_delay=1000;
# 一组最大多少个事务数
set global binlog_group_commit_sync_no_delay_count=100;# Slave并行复制参数
show variables like '%slave%';
# 停止slave
stop slave;
# 设置参数slave_parallel_type DATABASE是兼容5.6的基于数据库的设置
set global slave-parallel-type='LOGICAL_CLOCK';
# 工作线程数
set global slave-parallel-workers=8;# Slave中继日志
show variables like '%relay_log%';
# 日志使用TABLE效率更高可以提升50-80%，这些参数如果是只读，进入/etc/my.cnf配置
set global relay_log_info_repository='TABLE';
# master_info_repository参数自行选择，设置为TABLE效率更高
set global master_info_repository='TABLE';
set global relay_log_recovery=1;# my.cnf配置文件添加,有的参数set命令设置了有效，但是重启后就被重置了，保守还是使用配置文件比较稳妥
slave-parallel-type=LOGICAL_CLOCK
slave-parallel-workers=8
relay_log_info_repository=TABLE
master_info_repository=TABLE
relay_log_recovery=1# 重启MySQL
systemctl restart mysqld

MHA高可用搭建

服务器IP	角色
192.168.247.120	MySQL数据库Master
192.168.247.130	MySQL数据库Slave01
192.168.247.131	MySQL数据库Slave02
192.168.247.140	MHA Manager管理服务器

配置关键程序软连接（非RPM安装需要）

# 源文件路径自己根据需要修改，后面的路径必须保持一致
ln -s /data/mysql/bin/mysqlbinlog    /usr/bin/mysqlbinlog
ln -s /data/mysql/bin/mysql          /usr/bin/mysql

配置各节点互相

# 只需要一个节点设置就可以 192.168.247.140
# 删除原来的证书
rm -rf /root/.ssh
# 生成密钥
ssh-keygen
cd /root/.ssh
# 重命名
mv id_rsa.pub authorized_keys
# 发送证书到其他节点
scp  -r  /root/.ssh  192.168.247.120:/root
scp  -r  /root/.ssh  192.168.247.130:/root
scp  -r  /root/.ssh  192.168.247.131:/root # 所有节点验证，不需要输入密码
# MHA:
ssh 192.168.247.140 date
ssh 192.168.247.120 date
ssh 192.168.247.130 date
ssh 192.168.247.131 date
# Master:
ssh 192.168.247.140 date
ssh 192.168.247.120 date
ssh 192.168.247.130 date
ssh 192.168.247.131 date
# Slave01:
ssh 192.168.247.140 date
ssh 192.168.247.120 date
ssh 192.168.247.130 date
ssh 192.168.247.131 date
# Slave02:
ssh 192.168.247.140 date
ssh 192.168.247.120 date
ssh 192.168.247.130 date
ssh 192.168.247.131 date

MHA下载与安装

RPM	安装方	下载地址
mha4mysql-manager-0.58-0.el7.centos.noarch.rpm	MHA服务器	https://github.com/yoshinorim/mha4mysql-manager/releases/tag/v0.58
mha4mysql-node-0.58-0.el7.centos.noarch.rpm	MySQL服务器	https://github.com/yoshinorim/mha4mysql-node/releases/tag/v0.58

MySQL 从数据库修改配置

# 开启二进制日志，因为如果切换为主服务器就需要这个
log_bin=mysql-bin
sync-binlog=1 #每次写入都同步到binlog
binlog_format=ROW
binlog-ignore-db=performance_schema #忽略不同步
binlog-ignore-db=information_schema
binlog-ignore-db=sys

所有节点安装Node软件依赖包

# 安装依赖包
yum install perl-DBD-MySQL -y
# 安装node
rpm -ivh mha4mysql-node-0.58-0.el7.centos.noarch.rpm

MHA安装Manager软件

# 安装依赖
yum install -y perl-Config-Tiny epel-release perl-Log-Dispatch perl-Parallel-ForkManager perl-Time-HiRes
# 安装软件包
rpm -ivh mha4mysql-manager-0.58-0.el7.centos.noarch.rpm

创建MHA专用监控和管理用户（主库执行）

# 主库执行是由于自动同步到其他从库
grant all privileges on *.* to mha@'192.168.247.%' identified by 'mha';

MHA Manager配置文件

# 创建配置文件目录
mkdir -p /etc/mha
# 创建日志目录
mkdir -p /var/log/mha/app1
# 编辑mha配置文件
vim /etc/mha/app1.cnf
[server default]
manager_log=/var/log/mha/app1/manager
manager_workdir=/var/log/mha/app1
# 主数据库服务器的二进制日志路径
master_binlog_dir=/var/lib/mysql
user=mha
password=mha
# 一秒ping多少次
ping_interval=2
repl_password=root
repl_user=root
ssh_user=root
[server1]
hostname=192.168.247.120
candidate_master=1
port=3306
[server2]
hostname=192.168.247.130
candidate_master=1
port=3306
[server3]
hostname=192.168.247.131
candidate_master=1
port=3306

状态检测

# 互信检查
masterha_check_ssh  --conf=/etc/mha/app1.cnf [root@localhost ~]# masterha_check_ssh  --conf=/etc/mha/app1.cnf
Mon Oct  5 02:36:33 2020 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Mon Oct  5 02:36:33 2020 - [info] Reading application default configuration from /etc/mha/app1.cnf..
Mon Oct  5 02:36:33 2020 - [info] Reading server configuration from /etc/mha/app1.cnf..
Mon Oct  5 02:36:33 2020 - [info] Starting SSH connection tests..
Mon Oct  5 02:36:36 2020 - [debug]
Mon Oct  5 02:36:34 2020 - [debug]  Connecting via SSH from root@192.168.247.130(192.168.247.130:22) to root@192.168.247.120(192.168.247.120:22)..
Mon Oct  5 02:36:35 2020 - [debug]   ok.
Mon Oct  5 02:36:35 2020 - [debug]  Connecting via SSH from root@192.168.247.130(192.168.247.130:22) to root@192.168.247.131(192.168.247.131:22)..
Mon Oct  5 02:36:35 2020 - [debug]   ok.
Mon Oct  5 02:36:36 2020 - [debug]
Mon Oct  5 02:36:33 2020 - [debug]  Connecting via SSH from root@192.168.247.120(192.168.247.120:22) to root@192.168.247.130(192.168.247.130:22)..
Mon Oct  5 02:36:34 2020 - [debug]   ok.
Mon Oct  5 02:36:34 2020 - [debug]  Connecting via SSH from root@192.168.247.120(192.168.247.120:22) to root@192.168.247.131(192.168.247.131:22)..
Mon Oct  5 02:36:35 2020 - [debug]   ok.
Mon Oct  5 02:36:37 2020 - [debug]
Mon Oct  5 02:36:34 2020 - [debug]  Connecting via SSH from root@192.168.247.131(192.168.247.131:22) to root@192.168.247.120(192.168.247.120:22)..
Mon Oct  5 02:36:35 2020 - [debug]   ok.
Mon Oct  5 02:36:35 2020 - [debug]  Connecting via SSH from root@192.168.247.131(192.168.247.131:22) to root@192.168.247.130(192.168.247.130:22)..
Mon Oct  5 02:36:36 2020 - [debug]   ok.
Mon Oct  5 02:36:37 2020 - [info] All SSH connection tests passed successfully.

主从状态检测

# 注意，如果None of slaves can be master. Check failover configuration file or log-bin settings in my.cnf错误，那么就是从库没有开启二进制日志文件导致的。# 检测主从数据库服务器状态
masterha_check_repl  --conf=/etc/mha/app1.cnf# 执行成功日志
[root@localhost ~]# masterha_check_repl  --conf=/etc/mha/app1.cnf
Mon Oct  5 02:47:13 2020 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Mon Oct  5 02:47:13 2020 - [info] Reading application default configuration from /etc/mha/app1.cnf..
Mon Oct  5 02:47:13 2020 - [info] Reading server configuration from /etc/mha/app1.cnf..
Mon Oct  5 02:47:13 2020 - [info] MHA::MasterMonitor version 0.58.
Mon Oct  5 02:47:14 2020 - [info] GTID failover mode = 0
Mon Oct  5 02:47:14 2020 - [info] Dead Servers:
Mon Oct  5 02:47:14 2020 - [info] Alive Servers:
Mon Oct  5 02:47:14 2020 - [info]   192.168.247.120(192.168.247.120:3306)
Mon Oct  5 02:47:14 2020 - [info]   192.168.247.130(192.168.247.130:3306)
Mon Oct  5 02:47:14 2020 - [info]   192.168.247.131(192.168.247.131:3306)
Mon Oct  5 02:47:14 2020 - [info] Alive Slaves:
Mon Oct  5 02:47:14 2020 - [info]   192.168.247.130(192.168.247.130:3306)  Version=5.7.28-log (oldest major version between slaves) log-bin:enabled
Mon Oct  5 02:47:14 2020 - [info]     Replicating from 192.168.247.120(192.168.247.120:3306)
Mon Oct  5 02:47:14 2020 - [info]   192.168.247.131(192.168.247.131:3306)  Version=5.7.28-log (oldest major version between slaves) log-bin:enabled
Mon Oct  5 02:47:14 2020 - [info]     Replicating from 192.168.247.120(192.168.247.120:3306)
Mon Oct  5 02:47:14 2020 - [info] Current Alive Master: 192.168.247.120(192.168.247.120:3306)
Mon Oct  5 02:47:14 2020 - [info] Checking slave configurations..
Mon Oct  5 02:47:14 2020 - [warning]  relay_log_purge=0 is not set on slave 192.168.247.130(192.168.247.130:3306).
Mon Oct  5 02:47:14 2020 - [warning]  relay_log_purge=0 is not set on slave 192.168.247.131(192.168.247.131:3306).
Mon Oct  5 02:47:14 2020 - [info] Checking replication filtering settings..
Mon Oct  5 02:47:14 2020 - [info]  binlog_do_db= , binlog_ignore_db= information_schema,performance_schema,sys
Mon Oct  5 02:47:14 2020 - [info]  Replication filtering check ok.
Mon Oct  5 02:47:14 2020 - [info] GTID (with auto-pos) is not supported
Mon Oct  5 02:47:14 2020 - [info] Starting SSH connection tests..
Mon Oct  5 02:47:17 2020 - [info] All SSH connection tests passed successfully.
Mon Oct  5 02:47:17 2020 - [info] Checking MHA Node version..
Mon Oct  5 02:47:18 2020 - [info]  Version check ok.
Mon Oct  5 02:47:18 2020 - [info] Checking SSH publickey authentication settings on the current master..
Mon Oct  5 02:47:18 2020 - [info] HealthCheck: SSH to 192.168.247.120 is reachable.
Mon Oct  5 02:47:19 2020 - [info] Master MHA Node version is 0.58.
Mon Oct  5 02:47:19 2020 - [info] Checking recovery script configurations on 192.168.247.120(192.168.247.120:3306)..
Mon Oct  5 02:47:19 2020 - [info]   Executing command: save_binary_logs --command=test --start_pos=4 --binlog_dir=/var/lib/mysql --output_file=/var/tmp/save_binary_logs_test --manager_version=0.58 --start_file=mysql-bin.000001
Mon Oct  5 02:47:19 2020 - [info]   Connecting to root@192.168.247.120(192.168.247.120:22).. Creating /var/tmp if not exists..    ok.Checking output directory is accessible or not..ok.Binlog found at /var/lib/mysql, up to mysql-bin.000001
Mon Oct  5 02:47:19 2020 - [info] Binlog setting check done.
Mon Oct  5 02:47:19 2020 - [info] Checking SSH publickey authentication and checking recovery script configurations on all alive slave servers..
Mon Oct  5 02:47:19 2020 - [info]   Executing command : apply_diff_relay_logs --command=test --slave_user='mha' --slave_host=192.168.247.130 --slave_ip=192.168.247.130 --slave_port=3306 --workdir=/var/tmp --target_version=5.7.28-log --manager_version=0.58 --relay_log_info=/var/lib/mysql/relay-log.info  --relay_dir=/var/lib/mysql/  --slave_pass=xxx
Mon Oct  5 02:47:19 2020 - [info]   Connecting to root@192.168.247.130(192.168.247.130:22).. Checking slave recovery environment settings..Opening /var/lib/mysql/relay-log.info ... ok.Relay log found at /var/lib/mysql, up to mysql-relay-bin.000005Temporary relay log file is /var/lib/mysql/mysql-relay-bin.000005Checking 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.
Mon Oct  5 02:47:20 2020 - [info]   Executing command : apply_diff_relay_logs --command=test --slave_user='mha' --slave_host=192.168.247.131 --slave_ip=192.168.247.131 --slave_port=3306 --workdir=/var/tmp --target_version=5.7.28-log --manager_version=0.58 --relay_log_info=/var/lib/mysql/relay-log.info  --relay_dir=/var/lib/mysql/  --slave_pass=xxx
Mon Oct  5 02:47:20 2020 - [info]   Connecting to root@192.168.247.131(192.168.247.131:22).. Checking slave recovery environment settings..Opening /var/lib/mysql/relay-log.info ... ok.Relay log found at /var/lib/mysql, up to mysql-relay-bin.000005Temporary relay log file is /var/lib/mysql/mysql-relay-bin.000005Checking 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.
Mon Oct  5 02:47:20 2020 - [info] Slaves settings check done.
Mon Oct  5 02:47:20 2020 - [info]
192.168.247.120(192.168.247.120:3306) (current master)+--192.168.247.130(192.168.247.130:3306)+--192.168.247.131(192.168.247.131:3306)Mon Oct  5 02:47:20 2020 - [info] Checking replication health on 192.168.247.130..
Mon Oct  5 02:47:20 2020 - [info]  ok.
Mon Oct  5 02:47:20 2020 - [info] Checking replication health on 192.168.247.131..
Mon Oct  5 02:47:20 2020 - [info]  ok.
Mon Oct  5 02:47:20 2020 - [warning] master_ip_failover_script is not defined.
Mon Oct  5 02:47:20 2020 - [warning] shutdown_script is not defined.
Mon Oct  5 02:47:20 2020 - [info] Got exit code 0 (Not master dead).MySQL Replication Health is OK.

开启MHA

nohup masterha_manager --conf=/etc/mha/app1.cnf --remove_dead_master_conf --ignore_last_failover  < /dev/null> /var/log/mha/app1/manager.log 2>&1 &

查看MHA状态

# 执行命令
masterha_check_status --conf=/etc/mha/app1.cnf
app1 (pid:37744) is running(0:PING_OK), master:192.168.247.120# 查看监控的机器具体信息
mysql -umha -pmha -h 192.168.247.120 -e "show variables like 'server_id'"

故障模拟

# Msater主服务器杀掉mysql
pkill mysqld;# Slave执行查看从库状态是否已经没了，其中一个从库应该是变更为主库，可以看Master_Host显示的主机IP
show slave status \G;# MHA服务器查看状态，应该是不执行了
masterha_check_status --conf=/etc/mha/app1.cnf
# 结果 主机挂了，变为一主一从，不能满足MHA一主两从要求，所以MHA不再管理APP1集群
[root@localhost ~]# masterha_check_status --conf=/etc/mha/app1.cnf
app1 is stopped(2:NOT_RUNNING).
[1]+  完成                  nohup masterha_manager --conf=/etc/mha/app1.cnf --remove_dead_master_conf --ignore_last_failover < /dev/null > /var/log/mha/app1/manager.log 2>&1# 查看/etc/mha/app1.cnf配置是否少了一个配置
cat /etc/mha/app1.cnf
# 结果，少了192.168.247.120节点信息
[root@localhost ~]# cat /etc/mha/app1.cnf
[server default]
manager_log=/var/log/mha/app1/manager
manager_workdir=/var/log/mha/app1
master_binlog_dir=/var/lib/mysql
password=mha
ping_interval=2
repl_password=root
repl_user=root
ssh_user=root
user=mha[server2]
candidate_master=1
hostname=192.168.247.130
port=3306[server3]
candidate_master=1
hostname=192.168.247.131
port=3306# 查看日志
vim /var/log/mha/app1/manager

故障修复

启动之前的主库 systemctl restart mysqld;
修复主从将重新启动的数据库弄到新的主库中作为从库，查看MHA日志cat /var/log/mha/app1/manager可以找到以下信息

Mon Oct  5 16:21:26 2020 - [info]  All other slaves should start replication from here. Statement should be: CHANGE MASTER TO MASTER_HOST='192.168.247.130', MASTER_PORT=3306, MASTER_LOG_FILE='mysql-bin.000002', MASTER_LOG_POS=154, MASTER_USER='root', MASTER_PASSWORD='xxx';# 提取信息在重启的数据库中（192.168.247.120）执行
CHANGE MASTER TO MASTER_HOST='192.168.247.130', MASTER_PORT=3306, MASTER_LOG_FILE='mysql-bin.000002', MASTER_LOG_POS=154, MASTER_USER='root', MASTER_PASSWORD='root';# 启动slave
start slave;# 作为从库后，执行查看从库结果
show slave status \G;  # 发现主库变为了192.168.247.130 这样就加入了集群

修改MHA配置，添加192.168.247.120服务器信息 vim /etc/mha/app1.cnf

[server1]
candidate_master=1
hostname=192.168.247.120
port=3306

重启MHA

nohup masterha_manager --conf=/etc/mha/app1.cnf --remove_dead_master_conf --ignore_last_failover  < /dev/null> /var/log/mha/app1/manager.log 2>&1 &# 查看MHA状态
masterha_check_status --conf=/etc/mha/app1.cnf# 暂停MHA
masterha_stop  --conf=/etc/mha/app1.cnf

手动切换主备

如果MHA开启，那么默认情况下主备可以自动切换，当主机故障的时候，MHA将自动将备机切换为Master。

需要手动切换主备的情况

1）MHA故障，在这个时候Master同时也故障，就需要在Slave中选择一台作为Master。

2）Master和Slave正常运行，这时候需要添加一台服务器，并且将这台服务器作为Master，替代之前的Master机器。

# 情况一的操作手法：
# 暂停MHA
masterha_stop  --conf=/etc/mha/app1.cnf# 暂停Master,这里是模拟Master故障停机了
# Msater主服务器杀掉mysql
pkill mysqld;# 手工failover场景，master死掉，但是masterha_manager没有开启，可以通过手工failover：
masterha_master_switch --conf=/etc/mha/app1.cnf --dead_master_host=192.168.247.130 --master_state=dead --new_master_host=192.168.247.120 --ignore_last_failover# 情况二的操作手法：
# 手工在线切换，手动在线切换mha，切换时需要将在运行的mha停掉后才能切换。
# 方式一
masterha_master_switch --conf=/etc/mha/app1.cnf --master_state=alive --new_master_host=192.168.247.120 --orig_master_is_new_slave
# 方式二
# --orig_master_is_new_slave切换时加上此参数是将原master变为slave节点，如果不加此参数，原来的master将不启动
#--running_updates_limit=10000 切换时候选master如果有延迟的话，mha切换不能成功，加上此参数表示延迟在此时间范围内都可切换（单位为s），但是切换的时间长短是由recover时relay日志的大小决定
masterha_master_switch --conf=/etc/mha/app1.cnf --master_state=alive --new_master_host=192.168.247.120 --orig_master_is_new_slave --running_updates_limit=10000