MySQL读写分离与负载均衡--MHA与MaxScale
环境介绍
Part1:写在最前
看了某大牛的文章，讲述了一下MaxScale比LVS的好处多多，那您倒是放出来配置文件啊~~大牛说：
需要的单独找我吧，太长了配置文件……
看到这我心中久久不能平静啊。。。联系不上您呐 = =，于是各种资料各种找啊~各种坑各种血崩啊！~~~
由于不知道大牛的配置文件是什么样子，本文仅以随笔的形式，记录下实施过程。也欢迎您和我探讨您在实施MaxScale时遇到的各种问题和心得体会。
Part2:环境
MySQL5.7 MHA + MaxScale2.0
192.168.1.248 HE1 slave1
192.168.1.249 HE2 slave2
192.168.1.250 HE3 master
192.168.1.251 HE4 MHA-manager
Part3:MHA
MHA的优点不作赘述，看下原理图吧
从宕机崩溃的Master保存二进制日志事件(binlogevent)
识别含有最新更新的Slave
应用差异的中继日志(relaylog)到其他Slave
应用从Master保存的二进制日志事件
提升一个Slave为新的Master
使其他的Slave连接新的Master进行复制
构建MySQL5.7MHA
Part1:写在最前
MHA的部署不是本文的叙述重点，网上比比皆是。这里只记录下MySQL5.7的MHA搭建时的一些坑
Part2:坑
①mha4mysql-manager-0.57.tar.gz
②mha4mysql-node-0.57.tar.gz
Warning:警告这两个包首先你要搞到，虽然说0.56什么的不代表支持的mysql版本，但经过测试，想要在MySQL5.7上部署MHA，少走坑，请用0.57的。
Part3:安装包的位置
请在所有的节点包括Manager节点安装好你的mha4mysql-node-0.57.tar.gz，以保证后期在管理节点执行perl Makefile.PL的时候，你能如愿以偿的看到如下信息
[root@HE4 mha4mysql-manager-0.57]# perl Makefile.PL
*** Module::AutoInstall version 1.06
*** Checking for Perl dependencies...
[Core Features]
- DBI ...loaded. (1.609)
- DBD::mysql ...loaded. (4.013)
- Time::HiRes ...loaded. (1.9721)
- Config::Tiny ...loaded. (2.12)
- Log::Dispatch ...loaded. (2.26)
- Parallel::ForkManager ...loaded. (0.7.5)
- MHA::NodeConst ...loaded. (0.57)
*** Module::AutoInstall configuration finished.
Writing Makefile for mha4mysql::manager
Part4:一些常见错误记录
如果遇到
①这样
[root@HE2 bin]# masterha_check_repl --conf=/etc/mha/mha.conf
Tue Apr 5 22:09:32 2016 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Tue Apr 5 22:09:32 2016 - [info] Reading application default configuration from /etc/mha/mha.conf..
Tue Apr 5 22:09:32 2016 - [info] Reading server configuration from /etc/mha/mha.conf..
Tue Apr 5 22:09:32 2016 - [info] MHA::MasterMonitor version 0.57.
Tue Apr 5 22:09:32 2016 - [error][/usr/local/lib64/perl5/MHA/ServerManager.pm, ln188] There is no alive server. We can't do failover
Tue Apr 5 22:09:32 2016 - [error][/usr/local/lib64/perl5/MHA/MasterMonitor.pm, ln424] Error happened on checking configurations. at /usr/local/lib64/perl5/MHA/MasterMonitor.pm line 326
Tue Apr 5 22:09:32 2016 - [error][/usr/local/lib64/perl5/MHA/MasterMonitor.pm, ln523] Error happened on monitoring servers.
Tue Apr 5 22:09:32 2016 - [info] Got exit code 1 (Not master dead).
解决方案
用的不是默认端口3306，请修改你的配置文件
②这样
[root@HE4 ~]#
masterha_check_repl --conf=/etc/mha/mha.conf
Tue Apr 5 22:36:33 2016 - [warning] Global
configuration file /etc/masterha_default.cnf not found. Skipping.
Tue Apr 5 22:36:33 2016 - [info] Reading application
default configuration from /etc/mha/mha.conf..
Tue Apr 5 22:36:33 2016 - [info] Reading server
configuration from /etc/mha/mha.conf..
Tue Apr 5 22:36:33 2016 - [info] MHA::MasterMonitor
version 0.57.
Tue Apr 5 22:36:34 2016 - [info] GTID failover mode =
0
Tue Apr 5 22:36:34 2016 - [info] Dead Servers:
Tue Apr 5 22:36:34 2016 - [info] Alive Servers:
Tue Apr 5 22:36:34 2016 - [info] 192.168.1.250(192.168.1.250:4008)
Tue Apr 5 22:36:34 2016 - [info] 192.168.1.248(192.168.1.248:4008)
Tue Apr 5 22:36:34 2016 - [info] 192.168.1.249(192.168.1.249:4008)
Tue Apr 5 22:36:34 2016 - [info] Alive Slaves:
Tue Apr 5 22:36:34 2016 - [info] 192.168.1.248(192.168.1.248:4008) Version=5.6.16-log (oldest major version
between slaves) log-bin:enabled
Tue Apr 5 22:36:34 2016 - [info] Replicating from
192.168.1.250(192.168.1.250:4008)
Tue Apr 5 22:36:34 2016 - [info] Primary candidate for the new Master
(candidate_master is set)
Tue Apr 5 22:36:34 2016 - [info] 192.168.1.249(192.168.1.249:4008) Version=5.6.16-log (oldest major version
between slaves) log-bin:enabled
Tue Apr 5 22:36:34 2016 - [info] Replicating from
192.168.1.250(192.168.1.250:4008)
Tue Apr 5 22:36:34 2016 - [info] Not candidate for the new Master
(no_master is set)
Tue Apr 5 22:36:34 2016 - [info] Current Alive
Master: 192.168.1.250(192.168.1.250:4008)
Tue Apr 5 22:36:34 2016 - [info] Checking slave
configurations..
Tue Apr 5 22:36:34 2016 - [warning] relay_log_purge=0 is not set on slave
192.168.1.248(192.168.1.248:4008).
Tue Apr 5 22:36:34 2016 - [warning] relay_log_purge=0 is not set on slave
192.168.1.249(192.168.1.249:4008).
Tue Apr 5 22:36:34 2016 - [info] Checking replication
filtering settings..
Tue Apr 5 22:36:34 2016 - [info] binlog_do_db= , binlog_ignore_db=
Tue Apr 5 22:36:34 2016 - [info] Replication filtering check ok.
Tue Apr 5 22:36:34 2016 - [info] GTID (with auto-pos)
is not supported
Tue Apr 5 22:36:34 2016 - [info] Starting SSH
connection tests..
Tue Apr 5 22:36:35 2016 - [info] All SSH connection
tests passed successfully.
Tue Apr 5 22:36:35 2016 - [info] Checking MHA Node
version..
Tue Apr 5 22:36:36 2016 - [info] Version check ok.
Tue Apr 5 22:36:36 2016 - [info] Checking SSH
publickey authentication settings on the current master..
Tue Apr 5 22:36:36 2016 - [info] HealthCheck: SSH to
192.168.1.250 is reachable.
Tue Apr 5 22:36:36 2016 - [info] Master MHA Node
version is 0.57.
Tue Apr 5 22:36:36 2016 - [info] Checking recovery
script configurations on 192.168.1.250(192.168.1.250:4008)..
Tue Apr 5 22:36:36 2016 - [info] Executing command: save_binary_logs
--command=test --start_pos=4 --binlog_dir=/log/mysql
--output_file=/usr/local/mha/save_binary_logs_test --manager_version=0.57
--start_file=mysql-bin.000009
Tue Apr 5 22:36:36 2016 - [info] Connecting to
root@192.168.1.250(192.168.1.250:22)..
Creating /usr/local/mha if not exists..
Creating directory /usr/local/mha.. done.
ok.
Checking output directory is accessible or
not..
ok.
Binlog found at /log/mysql, up to
mysql-bin.000009
Tue Apr 5 22:36:36 2016 - [info] Binlog setting check
done.
Tue Apr 5 22:36:36 2016 - [info] Checking SSH
publickey authentication and checking recovery script configurations on all
alive slave servers..
Tue Apr 5 22:36:36 2016 - [info] Executing command : apply_diff_relay_logs
--command=test --slave_user='root' --slave_host=192.168.1.248
--slave_ip=192.168.1.248 --slave_port=4008 --workdir=/usr/local/mha
--target_version=5.6.16-log --manager_version=0.57
--relay_log_info=/data/mysql/relay-log.info
--relay_dir=/data/mysql/
--slave_pass=xxx
Tue Apr 5 22:36:36 2016 - [info] Connecting to
root@192.168.1.248(192.168.1.248:22)..
Can't exec
"mysqlbinlog": No such file or directory at
/usr/local/lib64/perl5/MHA/BinlogManager.pm line 106.
mysqlbinlog version
command failed with rc 1:0, please verify PATH, LD_LIBRARY_PATH, and client
options
at /usr/local/bin/apply_diff_relay_logs line
493
Tue Apr 5 22:36:36 2016 -
[error][/usr/local/lib64/perl5/MHA/MasterMonitor.pm, ln205] Slaves settings
check failed!
Tue Apr 5 22:36:36 2016 -
[error][/usr/local/lib64/perl5/MHA/MasterMonitor.pm, ln413] Slave configuration
failed.
Tue Apr 5 22:36:36 2016 -
[error][/usr/local/lib64/perl5/MHA/MasterMonitor.pm, ln424] Error happened on
checking configurations. at
/usr/local/bin/masterha_check_repl line 48
Tue Apr 5 22:36:36 2016 -
[error][/usr/local/lib64/perl5/MHA/MasterMonitor.pm, ln523] Error happened on
monitoring servers.
Tue Apr 5 22:36:36 2016 - [info] Got exit code 1 (Not
master dead).
MySQL Replication
Health is NOT OK!
解决方案
[root@HE1 MHA]# ln -s /usr/local/mysql/bin/mysqlbinlog /usr/bin/mysqlbinlog