centos下mysql高可用架构MHA搭建及测试故障转移
MHA项目网站https://code.google.com/p/mysql-master-ha/
一.环境介绍
1.主机部署
manager机:10.10.54.154
master机:10.10.54.156
slave1机:10.10.54.155(备用master)
slave2机:10.10.54.157
2.大致步骤
A.首先用ssh-keygen实现四台主机之间相互免密钥登录
B.安装MHAmha4mysql-node，mha4mysql-manager 软件包
C.建立master，slave1，slave2之间主从复制
D.管理机manager上配置MHA文件
E.masterha_check_ssh工具验证ssh信任登录是否成功
F.masterha_check_repl工具验证mysql复制是否成功
G.启动MHA manager,并监控日志文件
H.测试master(156)宕机后，是否会自动切换
3.说明：下面中括号中的主机名说明了当前操作是在哪台机子上进行的
二.首先用ssh-keygen实现四台主机之间相互免密钥登录
shell> ssh-keygen -t rsa -b 2048
shell> scp-copy-id root@10.10.54.155
shell> scp-copy-id root@10.10.54.156
shell> scp-copy-id root@10.10.54.157
在另外三台机子重复此步骤，使四台机子中的任何两台之间可以免密码登录
三.安装MHAmha4mysql-node，mha4mysql-manager 软件包
1.四台主机上安装MHAmha4mysql-node
shell> yum update
shell> yum -y install perl-DBD-MySQL ncftp
shell> wget http://mysql-master-ha.googlecode.com/files/mha4mysql-node-0.53-0.noarch.rpm
sehll> rpm -ivh mha4mysql-node-0.53-0.noarch.rpm 2.在manager机子上安装mha4mysql-manager
shell> yum install perl
shell> yum install cpan
shell> rpm -ivh mha4mysql-manager-0.53-0.el6.noarch.rpm
error:
perl(Config::Tiny) is needed by mha4mysql-manager-0.53-0.noarch
perl(Log::Dispatch) is needed by mha4mysql-manager-0.53-0.noarch
perl(Log::Dispatch::File) is needed by mha4mysql-manager-0.53-0.noarch
perl(Log::Dispatch::Screen) is needed by mha4mysql-manager-0.53-0.noarch
perl(Parallel::ForkManager) is needed by mha4mysql-manager-0.53-0.noarch
perl(Time::HiRes) is needed by mha4mysql-manager-0.53-0.noarch
shell> wget ftp://ftp.muug.mb.ca/mirror/centos/5.10/os/x86_64/CentOS/perl-5.8.8-41.el5.x86_64.rpm
shell> wget ftp://ftp.muug.mb.ca/mirror/centos/6.5/os/x86_64/Packages/compat-db43-4.3.29-15.el6.x86_64.rpm
shell> wget http://downloads.naulinux.ru/pub/NauLinux/6x/i386/sites/School/RPMS/perl-Log-Dispatch-2.27-1.el6.noarch.rpm
shell> wget http://dl.fedoraproject.org/pub/epel/6/i386/perl-Parallel-ForkManager-0.7.9-1.el6.noarch.rpm
shell> wget http://dl.fedoraproject.org/pub/epel/6/i386/perl-Mail-Sender-0.8.16-3.el6.noarch.rpm
shell> wget http://dl.fedoraproject.org/pub/epel/6/i386/perl-Mail-Sendmail-0.79-12.el6.noarch.rpm
shell> wget http://mirror.centos.org/centos/6/os/x86_64/Packages/perl-Time-HiRes-1.9721-136.el6.x86_64.rpm
shell> rpm -ivh perl-Parallel-ForkManager-0.7.9-1.el6.noarch.rpm perl-Log-Dispatch-2.27-1.el6.noarch.rpm perl-Mail-Sender-0.8.16-3.el6.noarch.rpm perl-Mail-Sendmail-0.79-12.el6.noarch.rpm perl-Time-HiRes-1.9721-136.el6.x86_64.rpm
shell> rpm -ivh mha4mysql-manager-0.53-0.el6.noarch.rpm 四.建立master，slave1，slave2之间主从复制
1.shell> vim /etc/my.cnf
#server-id 改为1
server-id=1
log-bin=mysql-bin
binlog_format=mixed
#授权操作
2.mysql> GRANT ALL PRIVILEGES ON *.* TO 'rep'@'10.10.54.%' IDENTIFIED BY 'rep123';
mysql> flush privileges;
3.mysql> show master status;
4.change master操作
mysql> change master to
master_host='10.10.54.156',
master_port=3306,
master_user='rep',
master_password='rep123',
master_log_file='mysql-bin.000001',
master_log_pos=112; 注意：slave1机子上也要授权，因为这个是备用master
5.mysql> GRANT ALL PRIVILEGES ON *.* TO 'rep'@'10.10.54.%' IDENTIFIED BY 'rep123';
6.查看主从复制是否成功的一些命令
mysql> start slave;
mysql> stop slave;
mysql> reset slave;
mysql> show slave status\G;
五.所有主机上设置复制权限帐号
mysql> GRANT ALL PRIVILEGES ON *.* TO 'mha_rep'@'10.10.2.10' IDENTIFIED BY '123456';
六.manager上配置MHA文件,管理各个节点
shell> mkdir -p /masterha/app1
shell> mkdir /etc/masterha
shell> vim /etc/masterha/app1.cnf
user=mha_rep ##mysql管理用戶名
password=123456
manager_workdir=/masterha/app1 #目录可以任意指定
manager_log=/masterha/app1/manager.log
remote_workdir=/masterha/app1
ssh_user=root #ssh免密钥登录的帐号名
repl_user=rep #mysql复制帐号，用来在主从机之间同步二进制日志等
repl_password=rep123
ping_interval=1 #ping间隔时间，用来检测master是否正常
hostname=10.10.54.155
#ssh_port=9999
master_binlog_dir=/data/ndb #mysql数据库目录
candidate_master=1 #master机宕掉后,优先启用这台作为新master
hostname=10.10.54.156
#ssh_port=9999
master_binlog_dir=/data/ndb
candidate_master=1
hostname=10.10.54.157
#ssh_port=9999
master_binlog_dir=/data/ndb
no_master=1 #设置no_master=1使主机不能成为新master 七.验证ssh信任登陆和mysql主从复制是否成功
1.masterha_check_ssh 验证ssh信任登陆
shell> masterha_check_ssh --conf=/etc/masterha/app1.cnf
Sun Mar2 17:45:38 2014 - ok.
Sun Mar2 17:45:38 2014 - All SSH connection tests passed successfully. 2.masterha_check_repl 验证mysql复制是否成功
shell> masterha_check_repl --conf=/etc/masterha/app1.cnf
---------------------------------------------------------
Sun Mar2 13:16:57 2014 - Slaves settings check done.
Sun Mar2 13:16:57 2014 -
10.10.54.156 (current master)
+--10.10.54.155
+--10.10.54.157
...
MySQL Replication Health is OK.
--------------------------------------------------------------- 八.启动MHA manager,并监控日志文件
shell> nohup masterha_manager --conf=/etc/masterha/app1.cnf > /tmp/mha_manager.log 2>&1
shell> tail -f /masterha/app1/manager.log
---------------------------------------------------------------
10.10.54.156 (current master)
+--10.10.54.155
+--10.10.54.157
...
Sun Mar2 13:09:25 2014 - Ping(SELECT) succeeded, waiting until MySQL doesn't respond..
----------------------------------------------------------------- 监控的manager.log文件表明MHA运行良好，正在 "waiting until MySQL doesn't respond"
九.测试master(156)宕机后，是否会自动切换
1.测试自动切换是否成功
当掉master机子
shell> /etc/init.d/myqld stop
当掉master后，manager上的监控文件/masterha/app1/manager.log显示错误信息，表示不能自动切换：
-----------------------------------------------------------
Sun Mar2 13:13:46 2014 - Got ERROR: Use of uninitialized value $msg in scalar chomp at /usr/share/perl5/vendor_perl/MHA/ManagerConst.pm line 90.
-----------------------------------------------------------
解决这个错误是在文件/usr/share/perl5/vendor_perl/MHA/ManagerConst.pm 第90行(chomp $msg)前加入一行：
$msg = "" unless($msg); 好了，错误解决了，下面我们再次重复上面步骤:
master上mysql服务：shell> /etc/init.d/mysqld stop
再次查看manager机子上监控文件内容
shell> tail -f tail -f /masterha/app1/manager.log
日志文件显示：
-----------------------------------------------------------
----- Failover Report -----
app1: MySQL Master failover 10.10.54.156 to 10.10.54.155 succeeded
Master 10.10.54.156 is down!
Check MHA Manager logs at mycentos4:/masterha/app1/manager.log for details.
Started automated(non-interactive) failover.
The latest slave 10.10.54.155(10.10.54.155:3306) has all relay logs for recovery.
Selected 10.10.54.155 as a new master.
10.10.54.155: OK: Applying all logs succeeded.
10.10.54.157: This host has the latest relay log events.
Generating relay diff files from the latest slave succeeded.
10.10.54.157: OK: Applying all logs succeeded. Slave started, replicating from 10.10.54.155.
10.10.54.155: Resetting slave info succeeded.
Master failover to 10.10.54.155(10.10.54.155:3306) completed successfully.
--------------------------------------------------------
2.切换成功后，检查replication状态
shell> /etc/init.d/mysqld start
shell> masterha_check_repl --conf=/etc/masterha/app1.cnf
--------------------------------------------------------------
Sun Mar2 13:22:11 2014 - Slaves settings check done.
Sun Mar2 13:22:11 2014 -
10.10.54.155 (current master)
+--10.10.54.156
+--10.10.54.157
...
MySQL Replication Health is OK.
---------------------------------------------------------------
上面的"10.10.54.155 (current master)" 这句表明master成功切换到155机子上
十.上一步测试之后，新master机为155，宕掉155机子，再次测试故障转移
1.启动管理节点
shell> nohup masterha_manager --conf=/etc/masterha/app1.cnf > /tmp/mha_manager.log 2>&1
2.启动日志检测，然后当掉新master(155)，然后查看监控文件变化
shell> tail -f /masterha/app1/manager.log
3.当掉155机子(即新的master)
shell> /etc/init.d/mysqld stop
4.查看manager主机上的监控文件变化
Last failover was done at 2014/03/02 13:02:47. Current time is too early to do failover again. If you want to do failover, manually remove /masterha/app1/app1.failover.complete and run this script again.
错误解决办法
1.日志文件提示切换master过快，需要删除/masterha/app1/app1.failover.complete
1.删除app1.failover.complete
shell> rm /masterha/app1/app1.failover.complete
5.重新测试：
master转移成功，重新转为156机子
--------------------------------------------------------
Master 10.10.54.155 is down!
Check MHA Manager logs at mycentos4:/masterha/app1/manager.log for details.
Started automated(non-interactive) failover.
The latest slave 10.10.54.156(10.10.54.156:3306) has all relay logs for recovery.
Selected 10.10.54.156 as a new master.
10.10.54.156: OK: Applying all logs succeeded.
10.10.54.157: This host has the latest relay log events.
Generating relay diff files from the latest slave succeeded.
10.10.54.157: OK: Applying all logs succeeded. Slave started, replicating from 10.10.54.156.
10.10.54.156: Resetting slave info succeeded.
Master failover to 10.10.54.156(10.10.54.156:3306) completed successfully.
-----------------------------------------------------------
//附:故障转移后，用命令恢复原来的master
1.在旧master上执行
mysql> reset master;
mysql> change master to master_host='10.10.54.155', master_port=3306, master_user='rep', master_password='rep123', master_log_file='mysql-bin.000031', master_log_pos=112;
mysql> start slave; #暂时先把旧master变为从
2.然后在manager节点上：
shell> masterha_master_switch --master_state=alive --conf=/etc/masterha/app1.cnf
##master成功切换回
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