mysql高可用架構方案之二(keepalived+lvs+讀寫分離+負載均衡)
mysql主從復制與lvs+keepalived實現負載高可用
目錄
1、前言 4
2、原理 4
2.1、概要介紹 4
2.2、工作原理 4
2.3、實際作用 4
3方案 4
3.1、環境 4
3.2、架構圖 5
3.3、設計原理 6
4、相關軟件安裝 6
4、配置mysql的主從 7
5、通過lvs+keepalived實現負載與熱備，並實現讀寫分離 8
1、前言
最近研究了下高可用的東西，這裡總結一下mysql主從復制讀寫分離度的高可用方案，可以提高服務器的使用效率，也可以提高提高維護效率。同時應用的效率也會有一定的提升，如果改造需要應用修改讀取的ip地址與寫入的ip地址，改造起來還算容易。
2、原理
2.1、概要介紹
如果將TCP/IP劃分為5層，則Keepalived就是一個類似於3~5層交換機制的軟件，具有3~5層交換功能，其主要作用是檢測web服務器的狀 態，如果某台web服務器故障，Keepalived將檢測到並將其從系統中剔除，當該web服務器工作正常後Keepalived自動將其加入到服務器 群中，這些工作全部自動完成，而不需要人工干預，只需要人工修復故障的web服務器即可。
2.2、工作原理
Keepalived基於VRRP協議來實現高可用解決方案，利用其避免單點故障，通常這個解決方案中，至少有2台服務器運行Keepalived，即一 台為MASTER，另一台為BACKUP，但對外表現為一個虛擬IP，MASTER會發送特定消息給BACKUP，當BACKUP收不到該消息時，則認為 MASTER故障了，BACKUP會接管虛擬IP，繼續提供服務，從而保證了高可用性，3層機理是發送ICMP數據包即PING給某台服務器，如果不痛，則認為其故障，並從服務器群中剔除。4層機理是檢測TCP端口號狀態來判斷某台服務器是否故障，如果故障，則從服務器群中剔除。5層機理是根據用戶的設定檢查某個服務器應用程序是否正常運行，如果不正常，則從服務器群中剔除。3、
2.3、實際作用
Keepalived+lvs主要用作RealServer的健康檢查，以及負載均衡設備MASTER和BACKUP之間failover的實現。
3方案
本案例先使用兩台linux做雙機MASTER-SLAVE高可用,實現都寫分離,用於提高查詢性能)，采用MYSQL5.6.x的半同步實現數據復制和同步，使用keepalived來監控MYSQL和提供讀寫VIP浮動。Keepalived在這裡主要用作RealServer的健康狀態檢查以及LoadBalance主機和BackUP主機之間failover的實現
任何一台主機宕機都不會影響對外提供服務（讀寫vip可以浮動），保持服務的高可用。
3.1、環境
主機A：192.168.150.171
主機B：192.168.150.172
W-VIP：192.168.150.173 （負責寫入）
R-VIP：192.168.150.174 （負責讀取）
Client：任意，只要能訪問以上三個IP即可
3.2、架構圖
具體架構圖如下：
3.3、設計原理(異常情況)
1、 服務器A和B，通過mysql的slave進程是用binlog同步數據。
2、 通過keepalived啟用兩個虛IP：W-VIP/R-VIP，一個負責寫入，一個負責讀取，實現讀寫分離。
3、 A和B都存在時，W-VIP下將請求轉發至主機A，R-VIP將請求轉發給A和B，實現負載均衡。
4、 當主機A異常時，B接管服務，W-VIP/R-VIP此時漂到了主機B上，此時這兩個虛IP下都是主機B，實現高可用
5、 當主機B異常時，R-VIP會將B踢出，其他不變
具體實現後的效果
正常狀態
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.150.173:3306 wrr persistent 60
-> 192.168.150.171:3306 Local 3 0 0
TCP 192.168.150.174:3306 wrr persistent 60
-> 192.168.150.172:3306 Route 3 0 0
-> 192.168.150.171:3306 Local 1 0 0
A故障後，B的狀態
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.150.173:3306 wrr persistent 60
-> 192.168.150.172:3306 Local 3 0 0
TCP 192.168.150.174:3306 wrr persistent 60
-> 192.168.150.172:3306 Local 3 0 0
架構圖
4、相關軟件安裝
1、 mysql 可以根據需要進行安裝，此處省略
2、 lvs+keepalived的安裝
關聯lvs與keepalived的ipvs所需的內核信息
ln -s /usr/src/kernels/2.6.18-194.el5-x86_64/ /usr/src/linux
安裝lvs
下載：wget http://www.linuxvirtualserver.org/software/kernel-2.6/ipvsadm-1.24.tar.gz
tar -zxvf ipvsadm-1.24.tar.gz
cd tar -zxvf ipvsadm-1.24
make
make install
yum install ipv* 安裝
驗證
ipvsadm –v
ipvsadm v1.24 2003/06/07 (compiled with getopt_long and IPVS v1.2.0)說明安裝成功
安裝keepalived
tar –zxvf keepalived-1.2.12.tar.gz
cd keepalived-1.2.12
./configure --prefix=/usr/local/keepalived/
make
make install
ln -s /usr/local/keepalived/etc/keepalived /etc/
ln -s /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/
ln -s /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
ln -s /usr/local/keepalived/bin/genhash /bin/
ln -s /usr/local/keepalived/sbin/keepalived /sbin/
configure時注意Use IPVS Framework、IPVS sync daemon support 、Use VRRP Framework要返回yes，否則無法關聯ipvs功能
4、配置mysql的主從
Master(210.171)的配置
vi /etc/my.cnf
添加如下內容：
server-id = 1 ##master ID
binlog-do-db = ppl ##允許同步的庫
binlog-ignore-db = mysql ##忽略同步的庫，也就是不能同步的庫
##配置文件中還需開啟log-bin，例如log-bin = mysql-bin
mysql –uroot –p
以下內容在mysql中執行
mysql> grant replication slave on *.* to ‘repdb01’@’%’ identified by '123456';
mysql>create database db01;
mysql>flush logs;
mysql>show master status;
mysql>use db01
mysql> create table test(name char);
返回一表格如下，記住File的內容，等下slave的配置中要用到
Slave的配置
vi /etc/my.cnf
添加如下內容：
server-id = 2 ##slave ID
master-host = 192.168.150.171 ##指定master的地址
master-user = repdb01 ##同步所用的賬號
master-password = 123456 ##同步所用的密碼
master-port = 3306 ##master上mysql的端口
replicate-do-db = db01 ##要同步的庫名
replicate-ignore-db = mysql ##忽略的庫名
slave-skip-errors = 1062 ##當同步異常時，那些錯誤跳過，本例為1062錯誤
#log-slave-updates ##同步的同時，也記錄自己的binlog日志，如果還有台slave是通過這台機器進行同步，那需要增加此項，
#skip-slave-start ##啟動時不自動開啟slave進程
#read-only ##將庫設為只讀模式，只能從master同步，不能直接寫入（避免自增鍵值沖突）
mysql –uroot –p
以下內容在mysql中執行
mysql>create database db01;
mysql>change master to master_log_file=’mysql-bin.000007’,master_log=106;
mysql>slave start;
mysql>show slave status \G
在返回值中查看，如果slave_IO_Runing與slave_SQL_Runing的值都為Yes說明同步成功
5、通過lvs+keepalived實現負載與熱備，並實現讀寫分離
Master上的配置
vi /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
router_id MySQL-HA
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 90
priority 100
advert_int 1
notify_master "/usr/local/mysql/bin/remove_slave.sh"
nopreempt
authentication {
auth_type PASS
auth_pass abcd1234
}
virtual_ipaddress {
192.168.150.173 label eth0:1
192.168.150.174 label eth0:2
}
}
virtual_server 192.168.150.173 3306 {
delay_loop 2
lb_algo wrr
lb_kind DR
persistence_timeout 60
protocol TCP
real_server 192.168.150.171 3306 {
weight 3
notify_down /usr/local/mysql/bin/mysql.sh
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 3306
}
}
}
virtual_server 192.168.150.174 3306 {
delay_loop 2
lb_algo wrr
lb_kind DR
persistence_timeout 60
protocol TCP
real_server 192.168.150.171 3306 {
weight 1
notify_down /usr/local/mysql/bin/mysql.sh
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 3306
}
}
real_server 192.168.150.172 3306 {
weight 3
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 3306
}
}
}
vi /usr/local/mysql/bin/remove_slave.sh
#!/bin/bash
user=root
password=123456
log=/root/mysqllog/remove_slave.log
#--------------------------------------------------------------------------------------
echo "`date`" >> $log
/usr/bin/mysql -u$user -p$password -e "set global read_only=OFF;reset master;stop slave;change master to master_host='localhost';" >> $log
/bin/sed -i 's#read-only#\#read-only#' /etc/my.cnf
chomd 755 /usr/local/mysql/bin/remove_slave.sh
vi /usr/local/mysql/bin/mysql.sh
#!/bin/bash
/etc/init.d/keepalived stop
Slave上的配置
vi /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
router_id MySQL-HA
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 90
priority 99
advert_int 1
notify_master "/usr/local/mysql/bin/remove_slave.sh"
authentication {
auth_type PASS
auth_pass ppl.com
}
virtual_ipaddress {
192.168.150.173 label eth0:1
192.168.150.174 label eth0:2
}
}
virtual_server 192.168.150.173 3306 {
delay_loop 2
lb_algo wrr
lb_kind DR
persistence_timeout 60
protocol TCP
real_server 192.168.150.172 3306 {
weight 3
notify_down /usr/local/mysql/bin/mysql.sh
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 3306
}
}
}
virtual_server 192.168.150.174 3306 {
delay_loop 2
lb_algo wrr
lb_kind DR
persistence_timeout 60
protocol TCP
real_server 192.168.150.172 3306 {
weight 3
notify_down /usr/local/mysql/bin/mysql.sh
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 3306
}
}
# real_server 192.168.150.172 3306 {
# weight 3
# TCP_CHECK {
# connect_timeout 10
# nb_get_retry 3
# delay_before_retry 3
# connect_port 3306
# }
# }
}
vi /usr/local/mysql/bin/remove_slave.sh
#!/bin/bash
user=root
password=123456
log=/root/mysqllog/remove_slave.log
#--------------------------------------------------------------------------------------
echo "`date`" >> $log
/usr/bin/mysql -u$user -p$password -e "set global read_only=OFF;reset master;stop slave;change master to master_host='localhost';" >> $log
/bin/sed -i 's#read-only#\#read-only#' /etc/my.cnf
chomd 755 /usr/local/mysql/bin/remove_slave.sh
vi /usr/local/mysql/bin/mysql.sh
#!/bin/bash
/etc/init.d/keepalived stop
vi /usr/local/keepalived/bin/lvs-rs.sh
#!/bin/bash
WEB_VIP=192.168.150.174
. /etc/rc.d/init.d/functions
case "$1" in
start)
ifconfig lo:0 $WEB_VIP netmask 255.255.255.255 broadcast $WEB_VIP
/sbin/route add -host $WEB_VIP dev lo:0
echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignore
echo "2" >/proc/sys/net/ipv4/conf/lo/arp_announce
echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore
echo "2" >/proc/sys/net/ipv4/conf/all/arp_announce
sysctl -p >/dev/null 2>&1
echo "RealServer Start OK"
;;
stop)
ifconfig lo:0 down
route del $WEB_VIP >/dev/null 2>&1
echo "0" >/proc/sys/net/ipv4/conf/lo/arp_ignore
echo "0" >/proc/sys/net/ipv4/conf/lo/arp_announce
echo "0" >/proc/sys/net/ipv4/conf/all/arp_ignore
echo "0" >/proc/sys/net/ipv4/conf/all/arp_announce
echo "RealServer Stoped"
;;
status)
# Status of LVS-DR real server.
islothere=`/sbin/ifconfig lo:0 | grep $WEB_VIP`
isrothere=`netstat -rn | grep "lo:0" | grep $web_VIP`
if [ ! "$islothere" -o ! "isrothere" ];then
# Either the route or the lo:0 device
# not found.
echo "LVS-DR real server Stopped."
else
echo "LVS-DR Running."
fi
;;
*)
# Invalid entry.
echo "$0: Usage: $0 {start|status|stop}"
exit 1
;;
esac
exit 0
chmod 755 /usr/local/keepalived/bin/lvs-rs.sh
echo “/usr/local/keepalived/bin/lvs-rs.sh start” >>/etc/rc.local
vi /etc/my.cnf
將這兩個參數前邊的 # 去掉，重啟mysql
#skip-slave-start
#read-only
登陸mysql，手動將slave進程啟動
mysql>slave start;
先啟動master上的keepalived，正常後再啟動slave上的。
啟動後 主庫可以查看ip a
[root@rac3 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:50:56:95:06:1f brd ff:ff:ff:ff:ff:ff
inet 192.168.150.171.171/24 brd 192.168.0.255 scope global eth0
inet 192.168.150.173/32 scope global eth0:1
inet 192.168.150.174/32 scope global eth0:2
inet6 fe80::250:56ff:fe95:61f/64 scope link
valid_lft forever preferred_lft forever
3: sit0: <NOARP> mtu 1480 qdisc noop
link/sit 0.0.0.0 brd 0.0.0.0
slave上查看
[root@rac1 keepalive]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet 192.168.150.174/32 brd 192.168.150.174 scope global lo:0
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:50:56:95:5e:b4 brd ff:ff:ff:ff:ff:ff
inet 192.168.150.188/24 brd 192.168.0.255 scope global eth0
inet 192.168.150.252/24 brd 192.168.0.255 scope global secondary eth0:1
inet 192.168.150.186/24 brd 192.168.0.255 scope global secondary eth0:4
inet6 fe80::250:56ff:fe95:5eb4/64 scope link
valid_lft forever preferred_lft forever
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:50:56:95:11:ba brd ff:ff:ff:ff:ff:ff
inet 10.10.10.188/24 brd 10.10.10.255 scope global eth1
inet 169.254.157.163/16 brd 169.254.255.255 scope global eth1:1
inet6 fe80::250:56ff:fe95:11ba/64 scope link
valid_lft forever preferred_lft forever
4: sit0: <NOARP> mtu 1480 qdisc noop
link/sit 0.0.0.0 brd 0.0.0.0
發現210.174 讀的vip 在主備機上都可以看到
210.173 寫入vip在主上才能看到
後續多台實驗進行中，敬請等待
