2套mysql主从互切脚本

由于mysql主主会出现些问题，比如幻读等，于是主从同步出现主故障时，需主从互切，刚好正在学python就用python写了个主从互切脚本，开始也有用shell写。
主要步骤为：
从上：stop slave
flush logs
再利用 show master status\G取二进制日志和位置为变量
主上：stop slave
然后用change master来切到从（利用上面的变量）
start slave
然后show slave status\G判断

下面为shell写的主从互切脚本 (在从mysql上操作，可进一步研究)

#!/bin/bash

#coding=utf-8

#author=min

#date=2015.10.16

#use:change slave to master when master was bad

master_ip=192.168.1.136                      # source master ip

slave_ip=192.168.1.134                       # source slave ip

root_passwd=******                           # root'password for logining myself mysql

user=paixian                                 # user to login master's mysql

passwd=********                         # password for user to login master's mysql

master_user=myslave                          # user to change master for master's mysql

master_password=********                      # user's password to change master for master's mysql

master_host=$(mysql -uroot -p$root_passwd -e 'show slave status\G'|grep Master_Host|awk -F': ' '{print $2}')  2>/dev/null #find the master host now

#echo $master_host    #to test the master host

[ $master_host = $master_ip ] && slave_host=$slave_ip || slave_host=$master_ip  2>/dev/null #definition the slave host

#echo $slave_host     #to test the slave host

mysql -uroot -p$root_passwd -e 'stop slave' 2>/dev/null  #stop the mysql slave thread
#echo $?1   #test the stop slave is yes or ok
mysql -uroot -p$root_passwd -e 'flush logs'   2>/dev/null #flush the binlogs

#echo $?2                                       #test flush logs is ok or no

bin_log=$(mysql -uroot -p$root_passwd -e 'show master status\G'|grep File|awk -F': ' '{print $2}') 2>/dev/null #find the master_log_file

#echo $bin_log   #test the master_log_file

pos=$(mysql -uroot -p$root_passwd -e 'show master status\G'|grep Position|awk -F': ' '{print $2}') 2>/dev/null #find the master_log_pos

#echo $pos     #test the master_log_pos

mysql -u$user -p$passwd -h$master_host -e "stop slave" 2>/dev/null #stop the mysql slave thread

#echo $?3      #03 ok   13 no   to test the stop slave threa is ok?

mysql -u$user -p$passwd -h$master_host -e "change  master to master_host='$slave_host',master_user='$master_user',master_password='$master_password',master_log_file='$bin_log',master_log_pos=$pos" 2>/dev/null #change slave to master

#echo $?4      #04 ok  14 no    to test the change slave to master is ok?

mysql -u$user -p$passwd -h$master_host -e "start slave"   2>/dev/null  #slave start  slave  thread

#echo $?5      #05 ok   15 no   to test the start slave thread is ok?

mysql -u$user -p$passwd -h$master_host -e "show slave status\G" 2>/dev/null #slave show slave status

#echo $?6  #06 ok 16 no  to test slave status

下面为python写的主从互切脚本（能在管理mysql的服务器上操作）

#!/usr/sbin/python
# ^-^ coding: utf-8 ^-^
# ^-^ author: chen min ^-^
# ^-^ time: 2015-10-22 ^-^
import MySQLdb
slave=raw_input('please input slave_ip:')
if slave=='192.168.1.134':
master='192.168.1.136'
else:
master='192.168.1.134'
global slave,master

def getpos():
conn = MySQLdb.Connect(
host = '%s'%slave,
port = 3306,
db = 'test',
user = 'paixian',
passwd = '***********',
charset = 'utf8'
)
cursor = conn.cursor(cursorclass=MySQLdb.cursors.DictCursor)
try:
#        print slave,master,type(slave)
cursor.execute("stop slave")
cursor.execute("flush logs")
sql = "show master status"
n = cursor.execute(sql)
a = cursor.fetchall()
bin_log = a[0].get('File')
pos = a[0].get('Position')
global bin_log,pos
conn.commit()
except Exception as e:
print e
finally:
cursor.close()
conn.close()

def changeslave():
conn1 = MySQLdb.Connect(
host = '%s'%master,
port = 3306,
db = 'test',
user = 'paixian',
passwd = '***********',
charset = 'utf8'
)
cursor1=conn1.cursor(cursorclass=MySQLdb.cursors.DictCursor)
try:
#        print bin_log,pos,slave,master
cursor1.execute("stop slave")
cursor1.execute("change master to master_host='%s', master_user='myslave', master_password='123123', master_log_file='%s', master_log_pos=%d"%(slave,bin_log,pos))
cursor1.execute("start slave")
m = cursor1.execute("show slave status")
m1 = cursor1.fetchall()
y = m1[0].get('Slave_IO_Running')
x = m1[0].get('Slave_SQL_Running')
#        print x,y
if x=='Yes' and y=='Yes':
print "slave to master is ok"
conn1.commit()
except Exception as e:
print e
finally:
cursor1.close()
conn1.close

try:
getpos()
changeslave()
except Exception as e:
print e