centos7下mysql双主+keepalived
一、keepalived简介
keepalived是vrrp协议的实现，原生设计目的是为了高可用ipvs服务，keepalived能够配置文件中的定义生成ipvs规则，并能够对各RS的健康状态进行检测；通过共用的虚拟IP地址对外提供服务；每个热备组内同一时刻只有一台主服务器提供服务，其他服务器处于冗余状态，若当前在线的服务器宕机，其虚拟IP地址将会被其他服务器接替（优先级决定接替顺序），实现高可用为后端主机提供服务。
二、keepalived组件
Keepalived组件介绍
core:keepalived核心组件，主进程的启动和维护，全局配置等。
vrrp stack:keepalived是基于vrrp协议实现高可用vps服务，vrrp则为相关子进程为其提供服务
check:检测keepalived的健康状态相关进程
system call:系统调用
watch dog:监控check和vrrp进程的看管者，check负责检测器子进程的健康状态，当其检测到master上的服务不可用时则通告vrrp将其转移至backup服务器上。
三 环境准备
操作系统：centos7.1.1511（core）
数据库： mysql5.7.21 社区版
master1 ：10.0.0.11 安装mysql 和keeplived
master2 ：10.0.0.12 安装mysql 和keeplived
VIP：10.0.0.20
要实现互为主从，就必须 mster1-->master2设置主从同步 同时 master2--->master1 也设置主从同步
四、Mysql主主同步环境部署
---------------master1服务器操作记录--------------- 在my.cnf文件的[mysqld]配置区域添加下面内容： [root@master1 ~]# vim /usr/local/mysql/my.cnf server-id = 1 log-bin = mysql-bin sync_binlog = 1 binlog_checksum = none binlog_format = mixed auto-increment-increment = 2 auto-increment-offset = 1 slave-skip-errors = all [root@master1 ~]# /etc/init.d/mysql restart Shutting down MySQL. SUCCESS! Starting MySQL.. SUCCESS!
创建一个复制用户
出了小问题，由于之前root用户的密码设置过于简单在创建复制用户时报如下错误
mysql> grant replication slave,replication client on *.* to repl@'10.0.0.%' identified by '1qaz@WSX'; ERROR 1820 (HY000): You must reset your password using ALTER USER statement before executing this statement.
按照提示将密码设置的复杂一点 在授权创建就没有问题了
mysql> alter user 'root'@'localhost' identified by '1qaz@WSX'; Query OK, 0 rows affected (0.00 sec) mysql> flush privileges; Query OK, 0 rows affected (0.00 sec)
mysql> grant replication slave,replication client on *.* to repl@'10.0.0.%' identified by '1qaz@WSX'; Query OK, 0 rows affected, 1 warning (0.00 sec) mysql> flush privileges; Query OK, 0 rows affected (0.00 sec)
锁表，待同步配置完成在解锁
mysql> flush tables with read lock; Query OK, 0 rows affected (0.00 sec)
查看当前的binlog以及数据所在位置
mysql> show master status; +------------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +------------------+----------+--------------+------------------+-------------------+ | mysql-bin.000006 | 996 | | | | +------------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)
---------------master2服务器操作记录--------------- 在my.cnf文件的[mysqld]配置区域添加下面内容： [root@master2 ~]# vim /usr/local/mysql/my.cnf server-id = 2 log-bin = mysql-bin sync_binlog = 1 binlog_checksum = none binlog_format = mixed auto-increment-increment = 2 auto-increment-offset = 2 slave-skip-errors = all [root@master2 ~]# /etc/init.d/mysql restart Shutting down MySQL.. SUCCESS! Starting MySQL.. SUCCESS!
mysql> grant replication slave,replication client on *.* to repl@'10.0.0.%' identified by '1qaz@WSX'; Query OK, 0 rows affected, 1 warning (0.01 sec) mysql> flush privileges; Query OK, 0 rows affected (0.00 sec)
mysql> flush tables with read lock;
Query OK, 0 rows affected (0.00 sec)
查看 master情况
mysql> show master status; +------------------+----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +------------------+----------+--------------+------------------+-------------------+ | mysql-bin.000001 | 150 | | | | +------------------+----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)
分别开启同步对方
---------------master1服务器做同步操作--------------- mysql> unlock tables; //先解锁，将对方数据同步到自己的数据库中 mysql> slave stop； mysql> change master to master_host='10.0.0.12',master_user='repl',master_password='1qaz@WSX',master_log_file='mysql-bin.000001',master_log_pos=150; Query OK, 0 rows affected, 2 warnings (0.01 sec)
mysql> start slave; Query OK, 0 rows affected (0.01 sec)
mysql> show slave status \G;
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
-------------master2服务器做同步操作--------------- mysql> unlock tables; //先解锁，将对方数据同步到自己的数据库中 mysql> slave stop； mysql> change master to master_host='10.0.0.11',master_user='repl',master_password='1qaz@WSX',master_log_file='mysql-bin.000006',master_log_pos=996; Query OK, 0 rows affected, 2 warnings (0.06 sec) mysql> start slave; Query OK, 0 rows affected (0.01 sec) mysql> show slave status \G;
Master_Log_File: mysql-bin.000006
Read_Master_Log_Pos: 996
Relay_Log_File: master2-relay-bin.000002
Relay_Log_Pos: 312
Relay_Master_Log_File: mysql-bin.000006
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
以上表明双方已经实现了mysql主主同步。
当运行一段时间后，要是发现同步有问题，比如只能单向同步，双向同步失效。可以重新执行下上面的change master同步操作，只不过这样同步后，只能同步在此之后的更新数据。下面开始进行数据验证：
-----------------主主同步效果验证--------------------- 1）在master1数据库上写入新数据 mysql> unlock tables; Query OK, 0 rows affected (0.00 sec) mysql> create database huanqiu; Query OK, 1 row affected (0.01 sec) mysql> use huanqiu; Database changed
mysql> create table if not exists haha ( id int(10) PRIMARY KEY AUTO_INCREMENT, name varchar(50) NOT NULL);
Query OK, 0 rows affected (0.04 sec)
mysql> insert into haha values(2,'guojing');
Query OK, 1 row affected (0.00 sec)
mysql> insert into haha values(1,"huangrong");
Query OK, 1 row affected (0.00 sec)
mysql> select * from haha;
+----+-----------+
| id | name |
+----+-----------+
| 1 | huangrong |
| 2 | guojing |
+----+-----------+
2 rows in set (0.00 sec)
然后在master2数据库上查看，发现数据已经同步过来了!
mysql> select * from huanqiu.haha;
+----+-----------+
| id | name |
+----+-----------+
| 1 | huangrong |
| 2 | guojing |
+----+-----------+
2 rows in set (0.00 sec)
2）在master2数据库上写入新数据 mysql> create database hehe; Query OK, 1 row affected (0.00 sec)
mysql> insert into huanqiu.haha values(3,"haha"),(4,"haha");
Query OK, 2 rows affected (0.00 sec)
Records: 2 Duplicates: 0 Warnings: 0
然后在master1数据库上查看，发现数据也已经同步过来了! mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | hehe | | huanqiu | | mysql | | performance_schema | | test | +--------------------+ 6 rows in set (0.00 sec)
mysql> select * from huanqiu.haha;
+----+-----------+
| id | name |
+----+-----------+
| 1 | huangrong |
| 2 | guojing |
| 3 | haha |
| 4 | haha |
+----+-----------+
4 rows in set (0.00 sec)
至此，Mysql主主同步环境已经实现。
五 配置mysql+keepalived 高可用环境
1）安装keepalived并将其配置成系统服务。master1和master2两台机器上同样进行如下操作：
[root@master1 ~]# yum install -y openssl-devel
[root@master1 ~]# cd /usr/local/src/
[root@master1 src]# wget http://www.keepalived.org/software/keepalived-1.3.5.tar.gz
[root@master1 src]# tar -zvxf keepalived-1.3.5.tar.gz
[root@master1 src]# cd keepalived-1.3.5
[root@master1 keepalived-1.3.5]# ./configure --prefix=/usr/local/keepalived
[root@master1 keepalived-1.3.5]# make && make install
[root@master1 keepalived-1.3.5]# cp /usr/local/src/keepalived-1.3.5/keepalived/etc/init.d/keepalived /etc/rc.d/init.d/
[root@master1 keepalived-1.3.5]# cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
[root@master1 keepalived-1.3.5]# mkdir /etc/keepalived/
[root@master1 keepalived-1.3.5]# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
[root@master1 keepalived-1.3.5]# cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
[root@master1 keepalived-1.3.5]# echo "/etc/init.d/keepalived start" >> /etc/rc.local
2）master1机器上的keepalived.conf配置。（下面配置中没有使用lvs的负载均衡功能，所以不需要配置虚拟服务器virtual server）
[root@master1 ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
[root@master1 ~]# vim /etc/keepalived/keepalived.conf ＃清空默认内容，直接采用下面配置：
! Configuration File for keepalived
global_defs {
notification_email {
ops@wangshibo.cn
tech@wangshibo.cn
}
notification_email_from ops@wangshibo.cn
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id MASTER-HA
}
vrrp_script chk_mysql_port { #检测mysql服务是否在运行。有很多方式，比如进程，用脚本检测等等
script "/opt/chk_mysql.sh" #这里通过脚本监测
interval 2 #脚本执行间隔，每2s检测一次
weight -5 #脚本结果导致的优先级变更，检测失败（脚本返回非0）则优先级 -5
fall 2 #检测连续2次失败才算确定是真失败。会用weight减少优先级（1-255之间）
rise 1 #检测1次成功就算成功。但不修改优先级
}
vrrp_instance VI_1 {
state MASTER
interface eth0 #指定虚拟ip的网卡接口
mcast_src_ip 10.0.0.11
virtual_router_id 51 #路由器标识，MASTER和BACKUP必须是一致的
priority 101 #定义优先级，数字越大，优先级越高，在同一个vrrp_instance下，MASTER的优先级必须大于BACKUP的优先级。这样MASTER故障恢复后，就可以将VIP资源再次抢回来
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.20
}
track_script {
chk_mysql_port
}
}
编写切换脚本。KeepAlived做心跳检测，如果Master的MySQL服务挂了(3306端口挂了),那么它就会选择自杀。Slave的KeepAlived通过心跳检测发现这个情况，就会将VIP的请求接管
[root@master1 ~]# vim /opt/chk_mysql.sh
#!/bin/bash
counter=$(netstat -na|grep "LISTEN"|grep "3306"|wc -l)
if [ "${counter}" -eq 0 ]; then
/etc/init.d/keepalived stop
fi
[root@master1 ~]# chmod 755 /opt/chk_mysql.sh
启动keepalived服务
[root@master1 ~]# /etc/init.d/keepalived start
正在启动 keepalived： [确定]
4）master2机器上的keepalived配置。master2机器上的keepalived.conf文件只修改priority为90、nopreempt不设置、real_server设置本地IP。
[root@master2 ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
[root@master2 ~]# >/etc/keepalived/keepalived.conf
[root@master2 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
ops@qq.com
tech@qq.com
}
notification_email_from ops@wangshibo.cn
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id MASTER-HA
}
vrrp_script chk_mysql_port {
script "/opt/chk_mysql.sh"
interval 2
weight -5
fall 2
rise 1
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
mcast_src_ip 10.0.0.12
virtual_router_id 51
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.0.0.20
}
track_script {
chk_mysql_port
}
}
[root@master2 ~]# cat /opt/chk_mysql.sh
#!/bin/bash
counter=$(netstat -na|grep "LISTEN"|grep "3306"|wc -l)
if [ "${counter}" -eq 0 ]; then
/etc/init.d/keepalived stop
fi
[root@master2 ~]# chmod 755 /opt/chk_mysql.sh
[root@master2 ~]# /etc/init.d/keepalived start
正在启动 keepalived： [确定]
我这里启动时出现了问题，分析日志
tail -f /var/log/message Mar 31 14:28:14 master1 systemd: Configuration file /usr/lib/systemd/system/ebtables.service is marked executable. Please remove executable permission bits. Proceeding anyway.
查看keepalived.service
# vi /lib/systemd/system/keepalived.service
[Unit]
Description=LVS and VRRP High Availability Monitor
After=syslog.target network-online.target
[Service]
Type=forking
# PIDFile=/usr/local/keepalived/var/run/keepalived.pid
# 上面这个注释掉 改成下面 因为这个默认路径不存在所以就无法写入进程ID文件
PIDFile=/var/run/keepalived.pid
KillMode=process
EnvironmentFile=-/usr/local/keepalived/etc/sysconfig/keepalived
ExecStart=/usr/local/keepalived/sbin/keepalived $KEEPALIVED_OPTIONS
ExecReload=/bin/kill -HUP $MAINPID
[Install]
WantedBy=multi-user.target
5）master1和master2两台服务器都要授权允许root用户远程登录，用于在客户端登陆测试！
mysql> grant all on *.* to root@'10.0.0.%' identified by "1qaz@WSX";
Query OK, 0 rows affected (0.00 sec)
mysql> flush privileges;
Query OK, 0 rows affected (0.01 sec)
6）在master1和master2两台机器上设置iptables防火墙规则，如下：[root@master1 ~]# cat /etc/sysconfig/iptables ........ -A INPUT -s 10.0.0.0/24 -d 224.0.0.18 -j ACCEPT #允许组播地址通信 -A INPUT -s 10.0.0.0/24 -p vrrp -j ACCEPT #允许VRRP（虚拟路由器冗余协）通信 -A INPUT -m state --state NEW -m tcp -p tcp --dport 3306 -j ACCEPT #开放mysql的3306端口 [root@master1 ~]# /etc/init.d/iptables restart
六 Mysql＋keepalived故障转移的高可用测试
1）通过Mysql客户端通过VIP连接，看是否连接成功。
比如，在远程一台测试机上连接，通过vip地址可以正常连接（下面的连接权限要是在服务端提前授权的）[root@master1 ~]# mysql -uroot -p1qaz@WSX -h10.0.0.20 mysql: [Warning] Using a password on the command line interface can be insecure. Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 11 Server version: 5.7.21-log MySQL Community Server (GPL) Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> select * from huanqiu.haha;
+----+-----------+
| id | name |
+----+-----------+
| 1 | huangrong |
| 2 | guojing |
| 3 | haha |
| 4 | haha |
+----+-----------+
4 rows in set (0.02 sec)
2）默认情况下，vip是在master1上的。使用"ip addr"命令查看vip切换情况
[root@master1 ~]# ip addr |grep 10.0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
inet 10.0.0.11/8 brd 10.255.255.255 scope global eth0
inet 10.0.0.20/32 scope global eth0
[root@master2 ~]# ip addr |grep 10.0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
inet 10.0.0.12/8 brd 10.255.255.255 scope global eth0
停止master1机器上的mysql服务，根据配置中的脚本，mysql服务停了，keepalived也会停，从而vip资源将会切换到master2机器上。（mysql服务没有起来的时候，keepalived服务也无法顺利启动！）
[root@master1 ~]# systemctl stop mysqld
[root@master1 ~]# ps -ef|grep mysql root 4431 2423 0 15:08 pts/0 00:00:00 grep --color=auto mysql [root@master1 ~]# ps -ef|grep keepalived root 4433 2423 0 15:08 pts/0 00:00:00 grep --color=auto keepalived
[root@master1 ~]# ip addr |grep 10.0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
inet 10.0.0.11/8 brd 10.255.255.255 scope global eth0
查看master2主机
[root@master2 ~]# ip addr |grep 10.0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
inet 10.0.0.12/8 brd 10.255.255.255 scope global eth0
inet 10.0.0.20/32 scope global eth0
3）再次启动master1的mysql和keepalived服务。（注意：如果restart重启mysql，那么还要启动下keepalived，因为mysql重启，根据脚本会造成keepalived关闭）注意：一定要先启动mysql服务，然后再启动keepalived服务。如果先启动keepalived服务，按照上面的配置，mysql没有起来，就会自动关闭keepalived。[root@master1 ~]# systemctl start mysqld [root@master1 ~]# /etc/init.d/keepalived start Starting keepalived (via systemctl): [ OK ]
[root@master1 ~]# ip addr |grep 10.0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
inet 10.0.0.11/8 brd 10.255.255.255 scope global eth0
inet 10.0.0.20/32 scope global eth0
[root@master2 ~]# ip addr |grep 10.0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
inet 10.0.0.12/8 brd 10.255.255.255 scope global eth0
此时虚拟ip又回到了 master1 主机上了
以上在vip资源切换过程中，对于客户端连接mysql（使用vip连接）来说几乎是没有任何影响的。
---------------------------------温馨提示（Keepalived的抢占和非抢占模式）---------------------------------------
keepalive是基于vrrp协议在linux主机上以守护进程方式，根据配置文件实现健康检查。
VRRP是一种选择协议，它可以把一个虚拟路由器的责任动态分配到局域网上的VRRP路由器中的一台。
控制虚拟路由器IP地址的VRRP路由器称为主路由器，它负责转发数据包到这些虚拟IP地址。
一旦主路由器不可用，这种选择过程就提供了动态的故障转移机制，这就允许虚拟路由器的IP地址可以作为终端主机的默认第一跳路由器。
keepalive通过组播，单播等方式（自定义），实现keepalive主备推选。工作模式分为抢占和非抢占（通过参数nopreempt来控制）。
1）抢占模式：
主服务正常工作时，虚拟IP会在主上，备不提供服务，当主服务优先级低于备的时候，备会自动抢占虚拟IP，这时，主不提供服务，备提供服务。
也就是说，工作在抢占模式下，不分主备，只管优先级。
如上配置，不管keepalived.conf里的state配置成master还是backup，只看谁的priority优先级高（一般而言，state为MASTER的优先级要高于BACKUP）。
priority优先级高的那一个在故障恢复后，会自动将VIP资源再次抢占回来！！
2）非抢占模式：
这种方式通过参数nopreempt（一般设置在advert_int的那一行下面）来控制。不管priority优先级，只要MASTER机器发生故障，VIP资源就会被切换到BACKUP上。
并且当MASTER机器恢复后，也不会去将VIP资源抢占回来，直至BACKUP机器发生故障时，才能自动切换回来。
千万注意：
nopreempt这个参数只能用于state为backup的情况，所以在配置的时候要把master和backup的state都设置成backup，这样才会实现keepalived的非抢占模式！
也就是说：
a）当state状态一个为master，一个为backup的时候，加不加nopreempt这个参数都是一样的效果。即都是根据priority优先级来决定谁抢占vip资源的，是抢占模式！
b）当state状态都设置成backup，如果不配置nopreempt参数，那么也是看priority优先级决定谁抢占vip资源，即也是抢占模式。
c）当state状态都设置成backup，如果配置nopreempt参数，那么就不会去考虑priority优先级了，是非抢占模式！即只有vip当前所在机器发生故障，另一台机器才能接管vip。即使优先级高的那一台机器恢复 后也不会主动抢回vip，只能等到对方发生故障，才会将vip切回来。
---------------------------------mysql状态检测脚本优化---------------------------------
上面的mysql监测脚本有点过于简单且粗暴，即脚本一旦监测到Master的mysql服务关闭，就立刻把keepalived服务关闭，从而实现vip转移！
下面对该脚本进行优化，优化后，当监测到Master的mysql服务关闭后，就会将vip切换到Backup上（但此时Master的keepalived服务不会被暴力kill）当Master的mysql服务恢复后，就会再次将VIP资源切回来！[root@master ~]# cat /opt/chk_mysql.sh
#!/bin/bash
MYSQL=/usr/bin/mysql
MYSQL_HOST=localhost
MYSQL_USER=root
MYSQL_PASSWORD=1qaz@WSX
CHECK_TIME=3
#mysql is working MYSQL_OK is 1 , mysql down MYSQL_OK is 0
MYSQL_OK=1
function check_mysql_helth (){
$MYSQL -h $MYSQL_HOST -u $MYSQL_USER -p${MYSQL_PASSWORD} -e "show status;" >/dev/null 2>&1
if [ $? = 0 ] ;then
MYSQL_OK=1
else
MYSQL_OK=0
fi
return $MYSQL_OK
}
while [ $CHECK_TIME -ne 0 ]
do
let "CHECK_TIME -= 1"
check_mysql_helth
if [ $MYSQL_OK = 1 ] ; then
CHECK_TIME=0
exit 0
fi
if [ $MYSQL_OK -eq 0 ] && [ $CHECK_TIME -eq 0 ]
then
pkill keepalived
exit 1
fi
sleep 1
done
一些事情一直在干，说不定以后就结果了呢
本文来自博客园，作者：chenjianwen，转载请注明原文链接：https://www.cnblogs.com/chenjw-note/p/12145815.html
