Linux学习-MySQL的主从复制高可用性解决方案MHA
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一、MHA简介
1、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。
2、MHA集群架构
3、MHA的工作原理
4、MHA软件组成
masterha_check_repl 检查mysql复制状况
masterha_manger 启动MHA
masterha_check_status 检测当前MHA运行状态
masterha_master_monitor 检测master是否宕机
masterha_master_switch 故障转移(自动或手动)
masterha_conf_host 添加或删除配置的server信息
apply_diff_relay_logs 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
filter_mysqlbinlog 去除不必要的ROLLBACK事件(MHA已不再使用此工具)
purge_relay_logs 清除中继日志(不会阻塞SQL线程)
master_ip_ailover_script 更新Application使用的masterip
shutdown_script 强制关闭master节点
report_script 发送报告
init_conf_load_script 加载初始配置参数
master_ip_online_change_script 更新master节点ip地址
(4) 配置文件:
global配置:为各application提供默认配置
application配置:为每个主从复制集群
二、实验环境
主机:4台,一台MHA Manager (192.168.214.17),三台主从复制架构(一主多从),master (192.168.214.27),slave1 (192.168.214.37),slave2 (192.168.214.47)
系统:CentOS7.6
数据库:mariadb-server-5.5.60(光盘yum源)
MHA软件包:mha4mysql-manager-0.56,mha4mysql-node-0.56
三、相关步骤
1、三台主从节点主点先安装mariadb数据库,使用光盘yum源
[root@centos7-27 ~]# yum install -y mariadb-server [root@centos7-37 ~]# yum install -y mariadb-server [root@centos7-47 ~]# yum install -y mariadb-server
2、准备MHA软件包,MHA Manager节点需要mha4mysql-manager和mha4mysql-node,其它三个节点只需要mha4mysql-node
[root@centos7-17 ~]# ll mha4mysql* -rw-r--r-- 1 root root 87119 Dec 9 10:32 mha4mysql-manager-0.56-0.el6.noarch.rpm -rw-r--r-- 1 root root 36326 Dec 9 10:32 mha4mysql-node-0.56-0.el6.noarch.rpm [root@centos7-27 ~]# ll mha4mysql* -rw-r--r-- 1 root root 36326 Dec 9 10:32 mha4mysql-node-0.56-0.el6.noarch.rpm [root@centos7-37 ~]# ll mha4mysql* -rw-r--r-- 1 root root 36326 Dec 9 10:32 mha4mysql-node-0.56-0.el6.noarch.rpm [root@centos7-47 ~]# ll mha4mysql* -rw-r--r-- 1 root root 36326 Dec 9 10:32 mha4mysql-node-0.56-0.el6.noarch.rpm
3、安装MHA软件包,MHA Manager节安装mha4mysql-manager时需要依赖epel源,这里使用阿里云的epel源
[root@centos7-17 ~]# cat /etc/yum.repos.d/base.repo [development] name=dvdbase repo baseurl=file:///mnt/cdrom/ enabled=1 gpgcheck=1 gpgkey=file:///mnt/cdrom/RPM-GPG-KEY-CentOS-7 [aliyunEpel] name=aliyun epel baseurl=https://mirrors.aliyun.com/epel/$releasever/$basearch enabled=1 gpgcheck=1 gpgkey=https://mirrors.aliyun.com/epel/RPM-GPG-KEY-EPEL-$releasever [root@centos7-17 ~]# yum install -y mha4mysql* [root@centos7-27 ~]# yum install -y mha4mysql-node-0.56-0.el6.noarch.rpm [root@centos7-37 ~]# yum install -y mha4mysql-node-0.56-0.el6.noarch.rpm [root@centos7-47 ~]# yum install -y mha4mysql-node-0.56-0.el6.noarch.rpm
4、配置主从复制(一主多从)
1). master节点
[root@centos7-27 ~]# vim /etc/my.cnf [mysqld] server-id=27 #添加此项 bin-log #添加此项 skip_name_resolve=1 #添加此项 datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock # Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0 # Settings user and group are ignored when systemd is used. # If you need to run mysqld under a different user or group, # customize your systemd unit file for mariadb according to the # instructions in http://fedoraproject.org/wiki/Systemd [mysqld_safe] log-error=/var/log/mariadb/mariadb.log pid-file=/var/run/mariadb/mariadb.pid # # include all files from the config directory # !includedir /etc/my.cnf.d
[root@centos7-27 ~]# systemctl start mariadb [root@centos7-27 ~]# mysql Welcome to the MariaDB monitor. Commands end with ; or \\g. Your MariaDB connection id is 2 Server version: 5.5.60-MariaDB MariaDB Server Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Type \'help;\' or \'\\h\' for help. Type \'\\c\' to clear the current input statement. MariaDB [(none)]> show master logs; +--------------------+-----------+ | Log_name | File_size | +--------------------+-----------+ | mariadb-bin.000001 | 245 | +--------------------+-----------+ 1 row in set (0.00 sec) MariaDB [(none)]> grant replication slave on *.* to repluser@\'192.168.214.%\' identified by \'centos\'; #添加主从复制用户 Query OK, 0 rows affected (0.00 sec) MariaDB [(none)]> grant all on *.* to mhauser@\'192.168.214.%\' identified by \'mhauser\'; #添加mha管理用户 Query OK, 0 rows affected (0.00 sec)
2). slave节点,两台节点的配置一样,以slave1(192.168.214.37)为例
[root@centos7-37 ~]# cat /etc/my.cnf [mysqld] server-id=37 #添加此项,slave2上的值记得改成47 log_bin #添加此项 read-only #添加此项 skip_name_resolve=1 #添加此项 relay_log_purge=0 #添加此项,是否清除中继日志,默认开启,这里把它关闭,因为需要用到中继日志 ...以下省略
[root@centos7-37 ~]# systemctl start mariadb [root@centos7-37 ~]# mysql Welcome to the MariaDB monitor. Commands end with ; or \\g. Your MariaDB connection id is 6 Server version: 5.5.60-MariaDB MariaDB Server Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Type \'help;\' or \'\\h\' for help. Type \'\\c\' to clear the current input statement. MariaDB [(none)]> CHANGE MASTER TO #配置连接主节点的信息 -> MASTER_HOST=\'192.168.214.27\', #主节点IP -> MASTER_USER=\'repluser\', #用于复制的账号 -> MASTER_PASSWORD=\'centos\', #密码 -> MASTER_LOG_FILE=\'mariadb-bin.000001\', #要复制的二进制日志 -> MASTER_LOG_POS=245; #开始复制的二进制日志的位置 Query OK, 0 rows affected (0.01 sec) MariaDB [(none)]> start slave; #开启复制线程 Query OK, 0 rows affected (0.00 sec) MariaDB [(none)]> show slave status\\G; #可用于查看开启状态
5、配置MHA Manager主机和其它三台主机的基于key验证的ssh服务
[root@centos7-17 ~]# ssh-keygen #生成密钥 Generating public/private rsa key pair. Enter file in which to save the key (/root/.ssh/id_rsa): 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:F8VxSwWdphlQLd1J9csOHEW932/ZIhi6agC2BxDJ89A root@centos7.localdomain The key\'s randomart image is: +---[RSA 2048]----+ |oo. o=oOBO| |o+ E ..=.B=| | .+ . .B o| | +. ..oo..| | . + S . o oo| | . o .. o o| | . . . o .+| | . . . . ..+| | ..... . o | +----[SHA256]-----+ [root@centos7-17 ~]# ls -a .ssh . .. id_rsa id_rsa.pub known_hosts #拷贝公钥到本地,然后把本地的.ssh文件夹复制到其它三台主机的/root/目录下 #即可实现四台主机之前相互之间都可以互机登录而不用输密码 #如果只是配置MHA Manage登陆其它三台,只需要用以下命令 # ssh-copy-id -i /root/.ssh/id_rsa.pub root@192.168.214.27 [root@centos7-17 ~]# ssh-copy-id -i /root/.ssh/id_rsa.pub root@192.168.214.17 [root@centos7-17 ~]# scp -r .ssh root@192.168.214.27:/root/ [root@centos7-17 ~]# scp -r .ssh root@192.168.214.37:/root/ [root@centos7-17 ~]# scp -r .ssh root@192.168.214.47:/root/
6、配置MHA Manager节点的配置文件
[root@centos7-17 ~]# mkdir /etc/mha/ [root@centos7-17 ~]# vim /etc/mha/app1.cnf [server default] user=mhauser #管理用户 password=mhauser #密码 manager_workdir=/data/mastermha/app1/ manager_log=/data/mastermha/app1/manager.log remote_workdir=/data/mastermha/app1/ ssh_user=root #ssh用户 repl_user=repluser #复制用户 repl_password=centos #密码 ping_interval=1 #监测master的时间1s [server1] hostname=192.168.214.27 candidate_master=1 #此选项表示优先使用此主节点 [server2] hostname=192.168.214.37 candidate_master=1 [server3] hostname=192.168.214.47
7、验证与启动
[root@centos7-17 ~]# masterha_check_ssh --conf=/etc/mha/app1.cnf #验证ssh [root@centos7-17 ~]# masterha_check_repl --conf=/etc/mha/app1.cnf #验证主从复制 [root@centos7-17 ~]# masterha_manager --conf=/etc/mha/app1.cnf #启动
注意:masterha_manager --conf=/etc/mha/app1.cnf 这种启动是一次性的(完成一次切换后就退出了),且只是在当前会话;建议后台启动运行:nohup masterha_manager --conf=/etc/mha/app1.cnf > mha.log
8、测试当mater节点断开时,主从的切换
[root@centos7-27 ~]# systemctl stop mariadb #关闭主节点数据库服务 [root@centos7-37 ~]# mysql Welcome to the MariaDB monitor. Commands end with ; or \\g. Your MariaDB connection id is 21 Server version: 5.5.60-MariaDB MariaDB Server Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others. Type \'help;\' or \'\\h\' for help. Type \'\\c\' to clear the current input statement. MariaDB [(none)]> show slave status\\G; #查询为空,说明slave1节点已提升为主节点 Empty set (0.00 sec) MariaDB [(none)]> show variables like \'read_only\'; #slave1节点的read-only选项也关闭了 +---------------+-------+ | Variable_name | Value | +---------------+-------+ | read_only | OFF | +---------------+-------+ 1 row in set (0.00 sec) [root@centos7-47 ~]# mysql MariaDB [(none)]> show slave status\\G; #在slave2上查看 *************************** 1. row *************************** Slave_IO_State: Waiting for master to send event Master_Host: 192.168.214.37 #主节点变为了slave1 Master_User: repluser Master_Port: 3306 Connect_Retry: 60 Master_Log_File: mariadb-bin.000001 Read_Master_Log_Pos: 245 Relay_Log_File: mariadb-relay-bin.000002 Relay_Log_Pos: 531 Relay_Master_Log_File: mariadb-bin.000001 Slave_IO_Running: Yes Slave_SQL_Running: Yes ...以下省略
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