xtrabackup搭建MySQL 8.0 主从复制

本次搭建的环境信息如下：
OS版本:Red Hat Enterprise Linux Server release 7.6 (Maipo)
MySQL版本：Server version: 8.0.37
xtrabackup版本：xtrabackup version 8.0.35-31 based on MySQL server 8.0.35 Linux (x86_64) (revision id: 55ec21d7)

本次采用物理备份和还原的方式来进行主从复制的初始化，相比于mysqldump，本方案适合数据量比较大的情况下，初始化很快，而且不像mysqldump的方式，从库不需要先进行初始化。

安装MySQL 8.0.37

groupadd mysql
useradd -g mysql -s /sbin/nologin -d /usr/local/mysql -MN mysql
cd /opt
unxz mysql-8.0.37-linux-glibc2.17-x86_64.tar.xz 
tar -xvf mysql-8.0.37-linux-glibc2.17-x86_64.tar 
cd /usr/local
ln -s /opt/mysql-8.0.37-linux-glibc2.17-x86_64 mysql
chown -R mysql:mysql /usr/local/mysql/
mkdir -p /data/mysql/mysql3306/{
   data,logs,tmp}
mv /opt/my.cnf /data/mysql/mysql3306/my3306.cnf
chown -R mysql:mysql /usr/local/mysql/
chown -R mysql:mysql /data/mysql/mysql3306/

/usr/local/mysql/bin/mysqld --defaults-file=/data/mysql/mysql3306/my3306.cnf --initialize
/usr/local/mysql/bin/mysqld --defaults-file=/data/mysql/mysql3306/my3306.cnf &

/usr/local/mysql/bin/mysql -uroot -p -S /tmp/mysql3306.sock
alter user user() identified by 'mysql';

安装xtrabackup

xtrabackup是社区开源产品。但是它不是MySQL自带的工具，需要我们自己进行安装。下面就说下安装过程
1、 下载安装包
由于xtrabackup有版本的区别，根据最佳实践，我们安装的MySQL版本为8.0.37，xtrabackup选择8.0以上最新版本即可，不选择2.4的版本，rpm安装，方便简单。
下载地址：https://www.percona.com/downloads

version:选择最新的
software：选择rpm，就选RHELx。如果是二进制，就选 Linux-Generic
2、安装，为了解决软件依赖问题，采用yum localinstall来安装

缺两个包:zstd和libev.so.4()(64bit)，镜像里面没有这两个包，我们手动下载匹配版本进行安装：

# rpm -ivh libev-4.15-7.el7.x86_64.rpm 
# rpm -ivh zstd-1.5.5-1.el7.x86_64.rpm

重新安装成功

[root@postgre opt]# yum localinstall percona-xtrabackup-80-8.0.35-31.1.el7.x86_64.rpm 
Loaded plugins: langpacks, product-id, search-disabled-repos, subscription-manager
This system is not registered with an entitlement server. You can use subscription-manager to register.
Examining percona-xtrabackup-80-8.0.35-31.1.el7.x86_64.rpm: percona-xtrabackup-80-8.0.35-31.1.el7.x86_64
Marking percona-xtrabackup-80-8.0.35-31.1.el7.x86_64.rpm to be installed
Resolving Dependencies
--> Running transaction check
---> Package percona-xtrabackup-80.x86_64 0:8.0.35-31.1.el7 will be installed
--> Processing Dependency: perl(DBD::mysql) for package: percona-xtrabackup-80-8.0.35-31.1.el7.x86_64
--> Processing Dependency: perl(Digest::MD5) for package: percona-xtrabackup-80-8.0.35-31.1.el7.x86_64
--> Running transaction check
---> Package perl-DBD-MySQL.x86_64 0:4.023-6.el7 will be installed
---> Package perl-Digest-MD5.x86_64 0:2.52-3.el7 will be installed
--> Processing Dependency: perl(Digest::base) >= 1.00 for package: perl-Digest-MD5-2.52-3.el7.x86_64
--> Running transaction check
---> Package perl-Digest.noarch 0:1.17-245.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

==========================================================================================================================================================================================
 Package                                     Arch                         Version                               Repository                                                           Size
==========================================================================================================================================================================================
Installing:
 percona-xtrabackup-80                       x86_64                       8.0.35-31.1.el7                       /percona-xtrabackup-80-8.0.35-31.1.el7.x86_64                       219 M
Installing for dependencies:
 perl-DBD-MySQL                              x86_64                       4.023-6.el7                           base                                                                140 k
 perl-Digest                                 noarch                       1.17-245.el7                          base                                                                 23 k
 perl-Digest-MD5                             x86_64                       2.52-3.el7                            base                                                                 30 k

Transaction Summary
==========================================================================================================================================================================================
Install  1 Package (+3 Dependent packages)

Total size: 219 M
Total download size: 193 k
Installed size: 219 M
Is this ok [y/d/N]: y
Downloading packages:
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total                                                                                                                                                     464 kB/s | 193 kB  00:00:00     
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Warning: RPMDB altered outside of yum.
  Installing : perl-DBD-MySQL-4.023-6.el7.x86_64                                                                                                                                      1/4 
  Installing : perl-Digest-1.17-245.el7.noarch                                                                                                                                        2/4 
  Installing : perl-Digest-MD5-2.52-3.el7.x86_64                                                                                                                                      3/4 
  Installing : percona-xtrabackup-80-8.0.35-31.1.el7.x86_64                                                                                                                           4/4 
base/productid                                                                                                                                                     | 1.6 kB  00:00:00     
  Verifying  : perl-Digest-1.17-245.el7.noarch                                                                                                                                        1/4 
  Verifying  : perl-Digest-MD5-2.52-3.el7.x86_64                                                                                                                                      2/4 
  Verifying  : percona-xtrabackup-80-8.0.35-31.1.el7.x86_64                                                                                                                           3/4 
  Verifying  : perl-DBD-MySQL-4.023-6.el7.x86_64                                                                                                                                      4/4 

Installed:
  percona-xtrabackup-80.x86_64 0:8.0.35-31.1.el7