MHA是众多使用MySQL数据库企业高可用的不二选择，它简单易用，功能强大，实现了基于MySQL replication架构的自动主从故障转移，本文主要描述了MHA自动切换的步骤，对切换过程做了演示以及进行了适当的分析，供大家参考和理解MHA以及MySQL的原理。

1、MHA自动切换的步骤
a、MHA manager启动时的校验阶段
根据配置文件校验复制配置以及识别当前的master
导致监控终止情形：复制配置异常，存在的异常slave，一些需要的脚本脚本异常
MHA manager启动前可以通过masterha_check_ssh以及masterha_check_repl检测

b、监控master server阶段
MHA manager启动成功后，输出日志[info] Ping(SELECT) succeeded, waiting until MySQL doesn't respond..
MHA会定期ping master，缺省的间隔为1秒，直到master死掉
MHA manager不会监控slave的状态，任意的Stopping/Restarting/Adding/Removing slaves不影响当前MHA监控
当添加或移除slave节点时，建议修改配置文件以及重启MHA manager

c、侦测到master server异常阶段
3次连续ping master失败，参数secondary_check_script可用于double check

d、开启failover阶段
MHA再次读取配置文件(防止主从配置已更改)，校验master以及当前masetr的从库
MHA也会校验诸如复制异常以及是否存在一些从库有不同的主
启动failover（排除上次failover失败或者failover时间间隔太短）

e、隔离master server阶段（可选）
如果配置文件定义了IP漂移脚本则此时会关闭master IP
如果配置文件定义了关闭master脚本，则调用脚本关闭master以避免脑裂

f、恢复一个新的master
从slave节点获取最新的end_log_pos (Read_Master_Log_Pos)位置
从上一步获取的位置开始，读取及保存crashed master全部二进制日志文件（ssh可达）
决定新的master（根据配置文件定义的优先级别）
产生差量的binary/relay log events并且apply到新的master

g、激活一个新的master
如果配置文件定义了IP漂移脚本则此时会将IP漂移到新master

i、恢复剩余的slave
对所有从库并行地产生差量binary/relay log events
并用apply差量binary/relay log events到各从库
启动复制

j、通知切换结果（可选）
邮件发送
备份作业，管理工具调整等

2、MHA配置信息
[root@vdbsrv4 ~]$ more /etc/masterha/app1.cnf
[server default]
manager_workdir=/var/log/masterha/app1
manager_log=/var/log/masterha/app1/manager.log
user=mha
password=xxx
ssh_user=root
repl_user=repl
repl_password=repl
ping_interval=1
shutdown_script=""
master_ip_online_change_script=""
report_script=""
master_ip_failover_script=/tmp/master_ip_failover

[server1]
hostname=vdbsrv1
master_binlog_dir=/data/mysqldata
[server2]
hostname=vdbsrv2
master_binlog_dir=/data/mysqldata
[server3]
hostname=vdbsrv3
master_binlog_dir=/data/mysqldata/
#candidate_master=1
[root@vdbsrv1 ~]# more /etc/hosts
127.0.0.1localhost.localdomain localhost
192.168.1.6vdbsrv1#master
192.168.1.7vdbsrv2#slave1
192.168.1.8vdbsrv3#slave2
192.168.1.12 vdbsrv4#manager
mysql> show slave hosts;
+-----------+---------+------+-----------+--------------------------------------+
| Server_id | Host| Port | Master_id | Slave_UUID|
+-----------+---------+------+-----------+--------------------------------------+
|1001 | vdbsrv2 | 3306 |1 | 75bef614-e342-11e4-921d-000c295fb2eb |
|1002 | vdbsrv3 | 3306 |1 | 091f79b8-e386-11e4-93d5-000c2943c830 |
+-----------+---------+------+-----------+--------------------------------------+
2 rows in set (0.00 sec)

3、演示切换
###开启主库VIP
[root@vdbsrv4 ~]# ssh vdbsrv1 "/sbin/ifconfig eth0:0 192.168.1.13 netmask 255.255.255.0 up"

###开启MHA manager
[root@vdbsrv4 ~]# nohup masterha_manager --conf=/etc/masterha/app1.cnf &

###使用sysbench产生事务
[root@vdbsrv1 ~]# sysbench --test=oltp\
> --oltp-table-size=5000000\
> --oltp-read-only=off\
> --init-rng=on\
> --num-threads=16\
> --max-requests=0\
> --oltp-dist-type=uniform\
> --max-time=180\
> --mysql-user=root\
> --mysql-socket=/tmp/mysql.sock \
> --mysql-password=''\
> --db-driver=mysql\
> --mysql-table-engine=innodb\
> --oltp-test-mode=complex\
> --mysql-db=replicatedb run
sysbench 0.4.12:multi-threaded system evaluation benchmark

###从库vdbsrv2停止io进程以模拟io滞后
[root@vdbsrv2 ~]# mysql -e 'stop slave io_thread'
[root@vdbsrv2 ~]# mysql -e 'show slave status\G' | egrep 'Slave_IO|Slave_SQL'
Slave_IO_State:
Slave_IO_Running: No###Author : Leshami
Slave_SQL_Running: Yes###Blog: http://blog.csdn.net/leshami
Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it

###2分钟后从库vdbsrv2启动io进程
[root@vdbsrv2 ~]# mysql -e 'start slave io_thread'

###从库vdbsrv3停止io进程以模拟io滞后
[root@vdbsrv3 ~]# mysql -e 'stop slave io_thread'

###模拟主库宕机
[root@vdbsrv4 ~]# ssh vdbsrv1 "killall -r mysqld"

###主库的sysbench被强制断开且伴随下列错误提示
[root@vdbsrv1 ~]#
.......
Doing OLTP test.
Running mixed OLTP test
Using Uniform distribution
Using "BEGIN" for starting transactions
Using auto_inc on the id column
Threads started!
ALERT: failed to execute mysql_stmt_execute(): Err1317 Query execution was interrupted
FATAL: database error, exiting...
ALERT: failed to execute mysql_stmt_execute(): Err1317 Query execution was interrupted
FATAL: database error, exiting...

###查看VIP漂移情况
[root@vdbsrv4 app1]# grep VIP /var/log/masterha/app1/manager.log
Disabling the VIP on old master: vdbsrv1
Enabling the VIP - 192.168.1.13/24 on the new master - vdbsrv2

###登陆到主机vdbsrv2 mysql
mysql> show variables like '%hostname%';
+---------------+---------+
| Variable_name | Value|
+---------------+---------+
| hostname| vdbsrv2 |
+---------------+---------+
1 row in set (0.00 sec)

###此时vdbsrv2已提升为master，vdbsrv3指向了vdbsrv2
mysql> show slave hosts;
+-----------+---------+------+-----------+--------------------------------------+
| Server_id | Host| Port | Master_id | Slave_UUID|
+-----------+---------+------+-----------+--------------------------------------+
|1002 | vdbsrv3 | 3306 |1001 | 091f79b8-e386-11e4-93d5-000c2943c830 |
+-----------+---------+------+-----------+--------------------------------------+
1 row in set (0.00 sec)

4、MHA日志初步剖析
[root@vdbsrv4 ~]# ls -hltr /var/log/masterha/*
total 32K
-rw-r--r-- 1 root root 143 Apr 20 14:30 saved_master_binlog_from_vdbsrv1_3306_20150420143022.binlog
-rw-r--r-- 1 root root 26K Apr 20 14:30 manager.log
-rw-r--r-- 1 root root0 Apr 20 14:30 app1.failover.complete

###具体日志信息manager.log
Mon Apr 20 14:27:41 2015 - [info] MHA::MasterMonitor version 0.56.
Mon Apr 20 14:27:42 2015 - [info] GTID failover mode = 0
Mon Apr 20 14:27:42 2015 - [info] Dead Servers:
Mon Apr 20 14:27:42 2015 - [info] Alive Servers:
Mon Apr 20 14:27:42 2015 - [info]vdbsrv1(192.168.1.6:3306)
Mon Apr 20 14:27:42 2015 - [info]vdbsrv2(192.168.1.7:3306)
Mon Apr 20 14:27:42 2015 - [info]vdbsrv3(192.168.1.8:3306)
Mon Apr 20 14:27:42 2015 - [info] Alive Slaves:
Mon Apr 20 14:27:42 2015 - [info]vdbsrv2(192.168.1.7:3306)Version=5.6.22-log (oldest major version between slaves) log-bin:enabled
Mon Apr 20 14:27:42 2015 - [info]Replicating from 192.168.1.6(192.168.1.6:3306)
Mon Apr 20 14:27:42 2015 - [info]vdbsrv3(192.168.1.8:3306)Version=5.6.22-log (oldest major version between slaves) log-bin:enabled
Mon Apr 20 14:27:42 2015 - [info]Replicating from 192.168.1.6(192.168.1.6:3306)
Mon Apr 20 14:27:42 2015 - [info] Current Alive Master: vdbsrv1(192.168.1.6:3306)
Mon Apr 20 14:27:42 2015 - [info] Checking slave configurations..
Mon Apr 20 14:27:42 2015 - [info]read_only=1 is not set on slave vdbsrv2(192.168.1.7:3306).
Mon Apr 20 14:27:42 2015 - [info] Checking replication filtering settings..
Mon Apr 20 14:27:42 2015 - [info]binlog_do_db= , binlog_ignore_db=
Mon Apr 20 14:27:42 2015 - [info]Replication filtering check ok.
Mon Apr 20 14:27:42 2015 - [info] GTID (with auto-pos) is not supported
Mon Apr 20 14:27:42 2015 - [info] Starting SSH connection tests..
Mon Apr 20 14:27:43 2015 - [info] All SSH connection tests passed successfully.
Mon Apr 20 14:27:43 2015 - [info] Checking MHA Node version..
Mon Apr 20 14:27:44 2015 - [info]Version check ok.
Mon Apr 20 14:27:44 2015 - [info] Checking SSH publickey authentication settings on the current master..
Mon Apr 20 14:27:44 2015 - [info] HealthCheck: SSH to vdbsrv1 is reachable.
Mon Apr 20 14:27:44 2015 - [info] Master MHA Node version is 0.56.
Mon Apr 20 14:27:44 2015 - [info] Checking recovery script configurations on vdbsrv1(192.168.1.6:3306)..
Mon Apr 20 14:27:44 2015 - [info]Executing command: save_binary_logs --command=test --start_pos=4 --binlog_dir=/data/mysqldata
--output_file=/var/tmp/save_binary_logs_test --manager_version=0.56 --start_file=mysql-bin.000020
Mon Apr 20 14:27:44 2015 - [info]Connecting to root@192.168.1.6(vdbsrv1:22)..
Creating /var/tmp if not exists..ok.
Checking output directory is accessible or not..
ok.
Binlog found at /data/mysqldata, up to mysql-bin.000020
Mon Apr 20 14:27:44 2015 - [info] Binlog setting check done.
Mon Apr 20 14:27:44 2015 - [info] Checking SSH publickey authentication and checking recovery script configurations on all alive slave servers..
Mon Apr 20 14:27:44 2015 - [info]Executing command : apply_diff_relay_logs --command=test --slave_user='mha' --slave_host=vdbsrv2
--slave_ip=192.168.1.7 --slave_port=3306 --workdir=/var/tmp --target_version=5.6.22-log --manager_version=0.56
--relay_log_info=/data/mysqldata/relay-log.info--relay_dir=/data/mysqldata/--slave_pass=xxx
Mon Apr 20 14:27:44 2015 - [info]Connecting to root@192.168.1.7(vdbsrv2:22)..
Checking slave recovery environment settings..
Opening /data/mysqldata/relay-log.info ... ok.
Relay log found at /data/mysqldata, up to vdbsrv2-relay-bin.000002
Temporary relay log file is /data/mysqldata/vdbsrv2-relay-bin.000002
Testing mysql connection and privileges.. done.
Testing mysqlbinlog output.. done.
Cleaning up test file(s).. done.
Mon Apr 20 14:27:45 2015 - [info]Executing command : apply_diff_relay_logs --command=test --slave_user='mha'
--slave_host=vdbsrv3 --slave_ip=192.168.1.8 --slave_port=3306 --workdir=/var/tmp --target_version=5.6.22-log
--manager_version=0.56 --relay_log_info=/data/mysqldata/relay-log.info--relay_dir=/data/mysqldata/--slave_pass=xxx
Mon Apr 20 14:27:45 2015 - [info]Connecting to root@192.168.1.8(vdbsrv3:22)..
Checking slave recovery environment settings..
Opening /data/mysqldata/relay-log.info ... ok.
Relay log found at /data/mysqldata, up to vdbsrv3-relay-bin.000002
Temporary relay log file is /data/mysqldata/vdbsrv3-relay-bin.000002
Testing mysql connection and privileges.. done.
Testing mysqlbinlog output.. done.
Cleaning up test file(s).. done.
Mon Apr 20 14:27:45 2015 - [info] Slaves settings check done.
Mon Apr 20 14:27:45 2015 - [info]
vdbsrv1(192.168.1.6:3306) (current master)
+--vdbsrv2(192.168.1.7:3306)
+--vdbsrv3(192.168.1.8:3306)
Mon Apr 20 14:27:45 2015 - [info] Checking master_ip_failover_script status:
Mon Apr 20 14:27:45 2015 - [info]/tmp/master_ip_failover --command=status --ssh_user=root --orig_master_host=vdbsrv1
--orig_master_ip=192.168.1.6 --orig_master_port=3306
IN SCRIPT TEST====/sbin/ifconfig eth0:0 down==/sbin/ifconfig eth0:0 192.168.1.13/24===
Checking the Status of the script.. OK
Mon Apr 20 14:27:45 2015 - [info]OK.
Mon Apr 20 14:27:45 2015 - [warning] shutdown_script is not defined.
Mon Apr 20 14:27:45 2015 - [info] Set master ping interval 1 seconds.
Mon Apr 20 14:27:45 2015 - [warning] secondary_check_script is not defined. It is highly recommended setting it to check master
reachability from two or more routes.
Mon Apr 20 14:27:45 2015 - [info] Starting ping health check on vdbsrv1(192.168.1.6:3306)..
Mon Apr 20 14:27:45 2015 - [info] Ping(SELECT) succeeded, waiting until MySQL doesn't respond..
Mon Apr 20 14:30:19 2015 - [warning] Got error on MySQL select ping: 2013 (Lost connection to MySQL server during query) ###侦测到错误
Mon Apr 20 14:30:19 2015 - [info] Executing SSH check script: save_binary_logs --command=test --start_pos=4 --binlog_dir=/data/mysqldata
--output_file=/var/tmp/save_binary_logs_test --manager_version=0.56 --binlog_prefix=mysql-bin
Mon Apr 20 14:30:19 2015 - [info] HealthCheck: SSH to vdbsrv1 is reachable.
Mon Apr 20 14:30:20 2015 - [warning] Got error on MySQL connect: 2003 (Can't connect to MySQL server on '192.168.1.6' (111))
Mon Apr 20 14:30:20 2015 - [warning] Connection failed 2 time(s)..
Mon Apr 20 14:30:21 2015 - [warning] Got error on MySQL connect: 2003 (Can't connect to MySQL server on '192.168.1.6' (111))
Mon Apr 20 14:30:21 2015 - [warning] Connection failed 3 time(s)..
Mon Apr 20 14:30:22 2015 - [warning] Got error on MySQL connect: 2003 (Can't connect to MySQL server on '192.168.1.6' (111))
Mon Apr 20 14:30:22 2015 - [warning] Connection failed 4 time(s)..
Mon Apr 20 14:30:22 2015 - [warning] Master is not reachable from health checker!
Mon Apr 20 14:30:22 2015 - [warning] Master vdbsrv1(192.168.1.6:3306) is not reachable!
Mon Apr 20 14:30:22 2015 - [warning] SSH is reachable.
Mon Apr 20 14:30:22 2015 - [info] Connecting to a master server failed. Reading configuration file /etc/masterha_default.cnf and
/etc/masterha/app1.cnf again, and trying to connect to all servers to check server status..
Mon Apr 20 14:30:22 2015 - [warning] Global configuration file /etc/masterha_default.cnf not found. Skipping.
Mon Apr 20 14:30:22 2015 - [info] Reading application default configuration from /etc/masterha/app1.cnf..
Mon Apr 20 14:30:22 2015 - [info] Reading server configuration from /etc/masterha/app1.cnf..
Mon Apr 20 14:30:22 2015 - [info] GTID failover mode = 0
Mon Apr 20 14:30:22 2015 - [info] Dead Servers:
Mon Apr 20 14:30:22 2015 - [info]vdbsrv1(192.168.1.6:3306)
Mon Apr 20 14:30:22 2015 - [info] Alive Servers:
Mon Apr 20 14:30:22 2015 - [info]vdbsrv2(192.168.1.7:3306)
Mon Apr 20 14:30:22 2015 - [info]vdbsrv3(192.168.1.8:3306)
Mon Apr 20 14:30:22 2015 - [info] Alive Slaves:
Mon Apr 20 14:30:22 2015 - [info]vdbsrv2(192.168.1.7:3306)Version=5.6.22-log (oldest major version between slaves) log-bin:enabled
Mon Apr 20 14:30:22 2015 - [info]Replicating from 192.168.1.6(192.168.1.6:3306)
Mon Apr 20 14:30:22 2015 - [info]vdbsrv3(192.168.1.8:3306)Version=5.6.22-log (oldest major version between slaves) log-bin:enabled
Mon Apr 20 14:30:22 2015 - [info]Replicating from 192.168.1.6(192.168.1.6:3306)
Mon Apr 20 14:30:22 2015 - [info] Checking slave configurations..
Mon Apr 20 14:30:22 2015 - [info]read_only=1 is not set on slave vdbsrv2(192.168.1.7:3306).
Mon Apr 20 14:30:22 2015 - [info] Checking replication filtering settings..
Mon Apr 20 14:30:22 2015 - [info]Replication filtering check ok.
Mon Apr 20 14:30:22 2015 - [info] Master is down!
Mon Apr 20 14:30:22 2015 - [info] Terminating monitoring script.
Mon Apr 20 14:30:22 2015 - [info] Got exit code 20 (Master dead).
Mon Apr 20 14:30:22 2015 - [info] MHA::MasterFailover version 0.56.
Mon Apr 20 14:30:22 2015 - [info] Starting master failover.
Mon Apr 20 14:30:22 2015 - [info]
Mon Apr 20 14:30:22 2015 - [info] * Phase 1: Configuration Check Phase..
Mon Apr 20 14:30:22 2015 - [info]
Mon Apr 20 14:30:22 2015 - [info] GTID failover mode = 0
Mon Apr 20 14:30:22 2015 - [info] Dead Servers:
Mon Apr 20 14:30:22 2015 - [info]vdbsrv1(192.168.1.6:3306)
Mon Apr 20 14:30:22 2015 - [info] Checking master reachability via MySQL(double check)...
Mon Apr 20 14:30:22 2015 - [info]ok.
Mon Apr 20 14:30:22 2015 - [info] Alive Servers:
Mon Apr 20 14:30:22 2015 - [info]vdbsrv2(192.168.1.7:3306)
Mon Apr 20 14:30:22 2015 - [info]vdbsrv3(192.168.1.8:3306)
Mon Apr 20 14:30:22 2015 - [info] Alive Slaves:
Mon Apr 20 14:30:22 2015 - [info]vdbsrv2(192.168.1.7:3306)Version=5.6.22-log (oldest major version between slaves) log-bin:enabled
Mon Apr 20 14:30:22 2015 - [info]Replicating from 192.168.1.6(192.168.1.6:3306)
Mon Apr 20 14:30:22 2015 - [info]vdbsrv3(192.168.1.8:3306)Version=5.6.22-log (oldest major version between slaves) log-bin:enabled
Mon Apr 20 14:30:22 2015 - [info]Replicating from 192.168.1.6(192.168.1.6:3306)
Mon Apr 20 14:30:22 2015 - [info] Starting Non-GTID based failover.
Mon Apr 20 14:30:22 2015 - [info]
Mon Apr 20 14:30:22 2015 - [info] ** Phase 1: Configuration Check Phase completed.
Mon Apr 20 14:30:22 2015 - [info]
Mon Apr 20 14:30:22 2015 - [info] * Phase 2: Dead Master Shutdown Phase.. ###隔离master server
Mon Apr 20 14:30:22 2015 - [info]
Mon Apr 20 14:30:22 2015 - [info] Forcing shutdown so that applications never connect to the current master..
Mon Apr 20 14:30:22 2015 - [info] Executing master IP deactivation script:
Mon Apr 20 14:30:22 2015 - [info]/tmp/master_ip_failover --orig_master_host=vdbsrv1 --orig_master_ip=192.168.1.6 --orig_master_port=3306
--command=stopssh --ssh_user=root
IN SCRIPT TEST====/sbin/ifconfig eth0:0 down==/sbin/ifconfig eth0:0 192.168.1.13/24===
Disabling the VIP on old master: vdbsrv1
Mon Apr 20 14:30:22 2015 - [info]done.
Mon Apr 20 14:30:22 2015 - [warning] shutdown_script is not set. Skipping explicit shutting down of the dead master.
Mon Apr 20 14:30:22 2015 - [info] * Phase 2: Dead Master Shutdown Phase completed.
Mon Apr 20 14:30:22 2015 - [info]
Mon Apr 20 14:30:22 2015 - [info] * Phase 3: Master Recovery Phase..
Mon Apr 20 14:30:22 2015 - [info]
Mon Apr 20 14:30:22 2015 - [info] * Phase 3.1: Getting Latest Slaves Phase..
Mon Apr 20 14:30:22 2015 - [info]
Mon Apr 20 14:30:22 2015 - [info] The latest binary log file/position on all slaves is mysql-bin.000020:315514388
Mon Apr 20 14:30:22 2015 - [info] Latest slaves (Slaves that received relay log files to the latest):
Mon Apr 20 14:30:22 2015 - [info]vdbsrv2(192.168.1.7:3306)Version=5.6.22-log (oldest major version between slaves) log-bin:enabled
Mon Apr 20 14:30:22 2015 - [info]Replicating from 192.168.1.6(192.168.1.6:3306)
Mon Apr 20 14:30:22 2015 - [info] The oldest binary log file/position on all slaves is mysql-bin.000020:313962621
Mon Apr 20 14:30:22 2015 - [info] Oldest slaves:
Mon Apr 20 14:30:22 2015 - [info]vdbsrv3(192.168.1.8:3306)Version=5.6.22-log (oldest major version between slaves) log-bin:enabled
Mon Apr 20 14:30:22 2015 - [info]Replicating from 192.168.1.6(192.168.1.6:3306)
Mon Apr 20 14:30:22 2015 - [info]
Mon Apr 20 14:30:22 2015 - [info] * Phase 3.2: Saving Dead Master's Binlog Phase..
Mon Apr 20 14:30:22 2015 - [info]
Mon Apr 20 14:30:23 2015 - [info] Fetching dead master's binary logs.. ###从dead master提取binlog
Mon Apr 20 14:30:23 2015 - [info] Executing command on the dead master vdbsrv1(192.168.1.6:3306): save_binary_logs --command=save
--start_file=mysql-bin.000020--start_pos=315514388 --binlog_dir=/data/mysqldata
--output_file=/var/tmp/saved_master_binlog_from_vdbsrv1_3306_20150420143022.binlog --handle_raw_binlog=1 --disable_log_bin=0
--manager_version=0.56
Creating /var/tmp if not exists..ok.
Concat binary/relay logs from mysql-bin.000020 pos 315514388 to mysql-bin.000020 EOF into
/var/tmp/saved_master_binlog_from_vdbsrv1_3306_20150420143022.binlog ..
Binlog Checksum enabled
Dumping binlog format description event, from position 0 to 120.. ok.
Dumping effective binlog data from /data/mysqldata/mysql-bin.000020 position 315514388 to tail(315514411).. ok.
Binlog Checksum enabled
Concat succeeded.
Mon Apr 20 14:30:23 2015 - [info] scp from root@192.168.1.6:/var/tmp/saved_master_binlog_from_vdbsrv1_3306_20150420143022.binlog to
local:/var/log/masterha/app1/saved_master_binlog_from_vdbsrv1_3306_20150420143022.binlog succeeded. ###复制dump的binlog到监控节点
Mon Apr 20 14:30:23 2015 - [info] HealthCheck: SSH to vdbsrv2 is reachable.
Mon Apr 20 14:30:24 2015 - [info] HealthCheck: SSH to vdbsrv3 is reachable.
Mon Apr 20 14:30:24 2015 - [info]
Mon Apr 20 14:30:24 2015 - [info] * Phase 3.3: Determining New Master Phase..
Mon Apr 20 14:30:24 2015 - [info]
Mon Apr 20 14:30:24 2015 - [info] Finding the latest slave that has all relay logs for recovering other slaves.. ###寻找最近的slave中继日志
Mon Apr 20 14:30:24 2015 - [info] Checking whether vdbsrv2 has relay logs from the oldest position..###用于恢复其他slave
Mon Apr 20 14:30:24 2015 - [info] Executing command: apply_diff_relay_logs --command=find --latest_mlf=mysql-bin.000020 --latest_rmlp=315514388
--target_mlf=mysql-bin.000020 --target_rmlp=313962621 --server_id=1001 --workdir=/var/tmp --timestamp=20150420143022
--manager_version=0.56 --relay_log_info=/data/mysqldata/relay-log.info--relay_dir=/data/mysqldata/
Opening /data/mysqldata/relay-log.info ... ok.
Relay log found at /data/mysqldata, up to vdbsrv2-relay-bin.000003
Fast relay log position search succeeded.
Target relay log file/position found. start_file:vdbsrv2-relay-bin.000003, start_pos:6265486.
Target relay log FOUND!
Mon Apr 20 14:30:24 2015 - [info] OK. vdbsrv2 has all relay logs.
Mon Apr 20 14:30:24 2015 - [info] Searching new master from slaves..###寻找及决定新的master
Mon Apr 20 14:30:24 2015 - [info]Candidate masters from the configuration file:
Mon Apr 20 14:30:24 2015 - [info]Non-candidate masters:
Mon Apr 20 14:30:24 2015 - [info] New master is vdbsrv2(192.168.1.7:3306)
Mon Apr 20 14:30:24 2015 - [info] Starting master failover..###执行failover
Mon Apr 20 14:30:24 2015 - [info]
From:
vdbsrv1(192.168.1.6:3306) (current master)
+--vdbsrv2(192.168.1.7:3306)
+--vdbsrv3(192.168.1.8:3306)
To:
vdbsrv2(192.168.1.7:3306) (new master)
+--vdbsrv3(192.168.1.8:3306)
Mon Apr 20 14:30:24 2015 - [info]
Mon Apr 20 14:30:24 2015 - [info] * Phase 3.3: New Master Diff Log Generation Phase..
Mon Apr 20 14:30:24 2015 - [info]
Mon Apr 20 14:30:24 2015 - [info]This server has all relay logs. No need to generate diff files from the latest slave.
Mon Apr 20 14:30:24 2015 - [info] Sending binlog..
Mon Apr 20 14:30:25 2015 - [info] scp from local:/var/log/masterha/app1/saved_master_binlog_from_vdbsrv1_3306_20150420143022.binlog to
root@vdbsrv2:/var/tmp/saved_master_binlog_from_vdbsrv1_3306_20150420143022.binlog succeeded.
Mon Apr 20 14:30:25 2015 - [info]
Mon Apr 20 14:30:25 2015 - [info] * Phase 3.4: Master Log Apply Phase..
Mon Apr 20 14:30:25 2015 - [info]
Mon Apr 20 14:30:25 2015 - [info] *NOTICE: If any error happens from this phase, manual recovery is needed.
Mon Apr 20 14:30:25 2015 - [info] Starting recovery on vdbsrv2(192.168.1.7:3306)..
Mon Apr 20 14:30:25 2015 - [info]Generating diffs succeeded.
Mon Apr 20 14:30:25 2015 - [info] Waiting until all relay logs are applied.
Mon Apr 20 14:30:36 2015 - [info]done.
Mon Apr 20 14:30:36 2015 - [info] Getting slave status..
Mon Apr 20 14:30:36 2015 - [info] This slave(vdbsrv2)'s Exec_Master_Log_Pos equals to Read_Master_Log_Pos(mysql-bin.000020:315514388).
No need to recover from Exec_Master_Log_Pos.
Mon Apr 20 14:30:36 2015 - [info] Connecting to the target slave host vdbsrv2, running recover script..###基于新主库Apply差量日志
Mon Apr 20 14:30:36 2015 - [info] Executing command: apply_diff_relay_logs --command=apply --slave_user='mha' --slave_host=vdbsrv2
--slave_ip=192.168.1.7--slave_port=3306 --apply_files=/var/tmp/saved_master_binlog_from_vdbsrv1_3306_20150420143022.binlog
--workdir=/var/tmp --target_version=5.6.22-log --timestamp=20150420143022 --handle_raw_binlog=1 --disable_log_bin=0
--manager_version=0.56 --slave_pass=xxx
Mon Apr 20 14:30:36 2015 - [info]
Applying differential binary/relay log files /var/tmp/saved_master_binlog_from_vdbsrv1_3306_20150420143022.binlog on vdbsrv2:3306.
This may take long time...
Applying log files succeeded.
Mon Apr 20 14:30:36 2015 - [info]All relay logs were successfully applied.
Mon Apr 20 14:30:36 2015 - [info] Getting new master's binlog name and position..
Mon Apr 20 14:30:36 2015 - [info]mysql-bin.000011:241926689
Mon Apr 20 14:30:36 2015 - [info]All other slaves should start replication from here. Statement should be: CHANGE MASTER TO
MASTER_HOST='vdbsrv2 or 192.168.1.7', MASTER_PORT=3306, MASTER_LOG_FILE='mysql-bin.000011', MASTER_LOG_POS=241926689, MASTER_USER='repl',
MASTER_PASSWORD='xxx';
Mon Apr 20 14:30:36 2015 - [info] Executing master IP activate script:###IP漂移
Mon Apr 20 14:30:36 2015 - [info]/tmp/master_ip_failover --command=start --ssh_user=root --orig_master_host=vdbsrv1 --orig_master_ip=192.168.1.6
--orig_master_port=3306 --new_master_host=vdbsrv2 --new_master_ip=192.168.1.7 --new_master_port=3306 --new_master_user='mha'
--new_master_password='xxx'
Unknown option: new_master_user
Unknown option: new_master_password
IN SCRIPT TEST====/sbin/ifconfig eth0:0 down==/sbin/ifconfig eth0:0 192.168.1.13/24===
Enabling the VIP - 192.168.1.13/24 on the new master - vdbsrv2
Mon Apr 20 14:30:36 2015 - [info]OK.
Mon Apr 20 14:30:36 2015 - [info] ** Finished master recovery successfully.
Mon Apr 20 14:30:36 2015 - [info] * Phase 3: Master Recovery Phase completed.
Mon Apr 20 14:30:36 2015 - [info]
Mon Apr 20 14:30:36 2015 - [info] * Phase 4: Slaves Recovery Phase..
Mon Apr 20 14:30:36 2015 - [info]
Mon Apr 20 14:30:36 2015 - [info] * Phase 4.1: Starting Parallel Slave Diff Log Generation Phase..
Mon Apr 20 14:30:36 2015 - [info]
Mon Apr 20 14:30:36 2015 - [info] -- Slave diff file generation on host vdbsrv3(192.168.1.8:3306) started, pid: 7726.
Check tmp log /var/log/masterha/app1/vdbsrv3_3306_20150420143022.log if it takes time..
Mon Apr 20 14:30:37 2015 - [info]
Mon Apr 20 14:30:37 2015 - [info] Log messages from vdbsrv3 ...
Mon Apr 20 14:30:37 2015 - [info]
Mon Apr 20 14:30:36 2015 - [info] Server vdbsrv3 received relay logs up to: mysql-bin.000020:313962621
Mon Apr 20 14:30:36 2015 - [info] Need to get diffs from the latest slave(vdbsrv2) up to: mysql-bin.000020:315514388
(using the latest slave's relay logs) ###此时vdbsrv3需要从vdbsrv2获取差量日志
Mon Apr 20 14:30:36 2015 - [info] Connecting to the latest slave host vdbsrv2, generating diff relay log files..
Mon Apr 20 14:30:36 2015 - [info] Executing command: apply_diff_relay_logs --command=generate_and_send --scp_user=root --scp_host=192.168.1.8
--latest_mlf=mysql-bin.000020 --latest_rmlp=315514388 --target_mlf=mysql-bin.000020 --target_rmlp=313962621 --server_id=1001
--diff_file_readtolatest=/var/tmp/relay_from_read_to_latest_vdbsrv3_3306_20150420143022.binlog --workdir=/var/tmp --timestamp=20150420143022
--handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.56 --relay_log_info=/data/mysqldata/relay-log.info --relay_dir=/data/mysqldata/
Mon Apr 20 14:30:37 2015 - [info]
Opening /data/mysqldata/relay-log.info ... ok.
Relay log found at /data/mysqldata, up to vdbsrv2-relay-bin.000003
Fast relay log position search succeeded.
Target relay log file/position found. start_file:vdbsrv2-relay-bin.000003, start_pos:6265486.
Concat binary/relay logs from vdbsrv2-relay-bin.000003 pos 6265486 to vdbsrv2-relay-bin.000003 EOF into
/var/tmp/relay_from_read_to_latest_vdbsrv3_3306_20150420143022.binlog ..###注，此时是从vdbsrv2中继日志获取
Binlog Checksum enabled
Binlog Checksum enabled
Dumping binlog format description event, from position 0 to 283.. ok.
Dumping effective binlog data from /data/mysqldata/vdbsrv2-relay-bin.000003 position 6265486 to tail(7817253).. ok.
Binlog Checksum enabled
Binlog Checksum enabled
Concat succeeded.
Generating diff relay log succeeded. Saved at /var/tmp/relay_from_read_to_latest_vdbsrv3_3306_20150420143022.binlog .
scp vdbsrv2:/var/tmp/relay_from_read_to_latest_vdbsrv3_3306_20150420143022.binlog to root@192.168.1.8(22) succeeded.
Mon Apr 20 14:30:37 2015 - [info]Generating diff files succeeded.
Mon Apr 20 14:30:37 2015 - [info] End of log messages from vdbsrv3.
Mon Apr 20 14:30:37 2015 - [info] -- Slave diff log generation on host vdbsrv3(192.168.1.8:3306) succeeded.
Mon Apr 20 14:30:37 2015 - [info] Generating relay diff files from the latest slave succeeded.
Mon Apr 20 14:30:37 2015 - [info]
Mon Apr 20 14:30:37 2015 - [info] * Phase 4.2: Starting Parallel Slave Log Apply Phase..
Mon Apr 20 14:30:37 2015 - [info]
Mon Apr 20 14:30:37 2015 - [info] -- Slave recovery on host vdbsrv3(192.168.1.8:3306) started, pid: 7735.
Check tmp log /var/log/masterha/app1/vdbsrv3_3306_20150420143022.log if it takes time..
Mon Apr 20 14:30:43 2015 - [info]
Mon Apr 20 14:30:43 2015 - [info] Log messages from vdbsrv3 ...
Mon Apr 20 14:30:43 2015 - [info]
Mon Apr 20 14:30:37 2015 - [info] Sending binlog..###这部分则是在原master宕机后未发送的binlog部分
Mon Apr 20 14:30:38 2015 - [info] scp from local:/var/log/masterha/app1/saved_master_binlog_from_vdbsrv1_3306_20150420143022.binlog to
root@vdbsrv3:/var/tmp/saved_master_binlog_from_vdbsrv1_3306_20150420143022.binlog succeeded.
Mon Apr 20 14:30:38 2015 - [info] Starting recovery on vdbsrv3(192.168.1.8:3306)..
Mon Apr 20 14:30:38 2015 - [info]Generating diffs succeeded.
Mon Apr 20 14:30:38 2015 - [info] Waiting until all relay logs are applied.
Mon Apr 20 14:30:38 2015 - [info]done.
Mon Apr 20 14:30:38 2015 - [info] Getting slave status..
Mon Apr 20 14:30:38 2015 - [info] This slave(vdbsrv3)'s Exec_Master_Log_Pos equals to Read_Master_Log_Pos(mysql-bin.000020:313962621).
No need to recover from Exec_Master_Log_Pos.
Mon Apr 20 14:30:38 2015 - [info] Connecting to the target slave host vdbsrv3, running recover script..
Mon Apr 20 14:30:38 2015 - [info] Executing command: apply_diff_relay_logs --command=apply --slave_user='mha' --slave_host=vdbsrv3
--slave_ip=192.168.1.8--slave_port=3306 --apply_files=/var/tmp/relay_from_read_to_latest_vdbsrv3_3306_20150420143022.binlog,
/var/tmp/saved_master_binlog_from_vdbsrv1_3306_20150420143022.binlog --workdir=/var/tmp --target_version=5.6.22-log
--timestamp=20150420143022 --handle_raw_binlog=1 --disable_log_bin=0 --manager_version=0.56 --slave_pass=xxx
Mon Apr 20 14:30:43 2015 - [info]
Concat all apply files to /var/tmp/total_binlog_for_vdbsrv3_3306.20150420143022.binlog ..
Copying the first binlog file /var/tmp/relay_from_read_to_latest_vdbsrv3_3306_20150420143022.binlog to
/var/tmp/total_binlog_for_vdbsrv3_3306.20150420143022.binlog.. ok.
Dumping binlog head events (rotate events), skipping format description events from
/var/tmp/saved_master_binlog_from_vdbsrv1_3306_20150420143022.binlog..Binlog Checksum enabled
dumped up to pos 120. ok.
/var/tmp/saved_master_binlog_from_vdbsrv1_3306_20150420143022.binlog has effective binlog events from pos 120.
Dumping effective binlog data from /var/tmp/saved_master_binlog_from_vdbsrv1_3306_20150420143022.binlog position 120 to tail(143).. ok.
Concat succeeded.
All apply target binary logs are concatinated at /var/tmp/total_binlog_for_vdbsrv3_3306.20150420143022.binlog .
Applying differential binary/relay log files /var/tmp/relay_from_read_to_latest_vdbsrv3_3306_20150420143022.binlog,
/var/tmp/saved_master_binlog_from_vdbsrv1_3306_20150420143022.binlog on vdbsrv3:3306. This may take long time...
Applying log files succeeded.
Mon Apr 20 14:30:43 2015 - [info]All relay logs were successfully applied.
Mon Apr 20 14:30:43 2015 - [info]Resetting slave vdbsrv3(192.168.1.8:3306) and starting replication from the new master vdbsrv2(192.168.1.7:3306)..
Mon Apr 20 14:30:43 2015 - [info]Executed CHANGE MASTER.
Mon Apr 20 14:30:43 2015 - [info]Slave started.
Mon Apr 20 14:30:43 2015 - [info] End of log messages from vdbsrv3.
Mon Apr 20 14:30:43 2015 - [info] -- Slave recovery on host vdbsrv3(192.168.1.8:3306) succeeded.
Mon Apr 20 14:30:43 2015 - [info] All new slave servers recovered successfully.
Mon Apr 20 14:30:43 2015 - [info]
Mon Apr 20 14:30:43 2015 - [info] * Phase 5: New master cleanup phase..
Mon Apr 20 14:30:43 2015 - [info]
Mon Apr 20 14:30:43 2015 - [info] Resetting slave info on the new master..
Mon Apr 20 14:30:43 2015 - [info]vdbsrv2: Resetting slave info succeeded.
Mon Apr 20 14:30:43 2015 - [info] Master failover to vdbsrv2(192.168.1.7:3306) completed successfully.
Mon Apr 20 14:30:43 2015 - [info]
----- Failover Report -----
app1: MySQL Master failover vdbsrv1(192.168.1.6:3306) to vdbsrv2(192.168.1.7:3306) succeeded
Master vdbsrv1(192.168.1.6:3306) is down!###整个failover总时间14:30:43-14:30:19=24s
Check MHA Manager logs at vdbsrv4:/var/log/masterha/app1/manager.log for details.
【MHA 自动故障转移步骤及过程剖析】Started automated(non-interactive) failover.
Invalidated master IP address on vdbsrv1(192.168.1.6:3306)
The latest slave vdbsrv2(192.168.1.7:3306) has all relay logs for recovery.
Selected vdbsrv2(192.168.1.7:3306) as a new master.
vdbsrv2(192.168.1.7:3306): OK: Applying all logs succeeded.
vdbsrv2(192.168.1.7:3306): OK: Activated master IP address.
vdbsrv3(192.168.1.8:3306): Generating differential relay logs up to vdbsrv2(192.168.1.7:3306)succeeded.
Generating relay diff files from the latest slave succeeded.
vdbsrv3(192.168.1.8:3306): OK: Applying all logs succeeded. Slave started, replicating from vdbsrv2(192.168.1.7:3306)
vdbsrv2(192.168.1.7:3306): Resetting slave info succeeded.
Master failover to vdbsrv2(192.168.1.7:3306) completed successfully.

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