Linux HA集群之Keepalived
大纲一、什么是Keepalived
二、Keepalived工作原理
三、Keepalived配置过程
一、什么是Keepalived
Keepalived是用C写的简单的一个路由软件，这个项目的主要目标是对Linux系统和基于Linux的基础设施提供简单而强大负载均衡和高可用性。负载均衡架构依赖于众所周知的和广泛使用的Linux虚拟服务器（IPVS）内核模块提供第四层负载均衡。另一方面，高可用性是通过VRRP协议实现。
Keepalived的作用是检测web服务器的状态，如果有一台web服务器死机，或工作出现故障，Keepalived将检测到，并将有故障的web服务器从系统中剔除，当web服务器工作正常后Keepalived自动将web服务器加入到服务器群中，这些工作全部自动完成，不需要人工干涉，需要人工做的只是修复故障的web服务器。
二、Keepalived工作原理
Layer3,4&7工作在IP/TCP协议栈的IP层，TCP层，及应用层,原理分别如下：
[*] Layer3：Keepalived使用Layer3的方式工作式时，Keepalived会定期向服务器群中的服务器发送一个ICMP的数据包（既我们平时用的Ping程序）,如果发现某台服务的IP地址没有激活，Keepalived便报告这台服务器失效，并将它从服务器群中剔除，这种情况的典型例子是某台服务器被非法关机。Layer3的方式是以服务器的IP地址是否有效作为服务器工作正常与否的标准。
[*] Layer4:如果您理解了Layer3的方式，Layer4就容易了。Layer4主要以TCP端口的状态来决定服务器工作正常与否。如web server的服务端口一般是80，如果Keepalived检测到80端口没有启动，则Keepalived将把这台服务器从服务器群中剔除。
[*] Layer7：Layer7就是工作在具体的应用层了，比Layer3,Layer4要复杂一点，在网络上占用的带宽也要大一些。Keepalived将根据用户的设定检查服务器程序的运行是否正常，如果与用户的设定不相符，则Keepalived将把服务器从服务器群中剔除。
Software Design
http://s2.运维网.com/wyfs02/M00/79/A4/wKioL1aXPDXjdyGFAACUn7rdsas433.gif
三、Keepalived配置过程
系统环境
CentOS5.8 x86_64
Director
Master 172.16.1.101
Slave 172.16.1.105
RealServer
node1.network.com node1 172.16.1.103
node2.network.com node2 172.16.1.104
软件包
[*] ipvsadm-1.24-13.el5.x86_64.rpm
[*] keepalived-1.2.1-5.el5.x86_64.rpm
[*] httpd-2.2.15-47.el6.centos.1.x86_64.rpm
拓扑图
http://s4.运维网.com/wyfs02/M00/79/9F/wKioL1aW_GiTmCFQAAHjepcnLLg813.jpg
1、时间同步
# ntpdate s2c.time.edu.cn
# ntpdate s2c.time.edu.cn
# ntpdate s2c.time.edu.cn
# ntpdate s2c.time.edu.cn
可根据需要在每个节点上定义crontab任务
# which ntpdate
/sbin/ntpdate
# echo "*/5 * * * * /sbin/ntpdate s2c.time.edu.cn &> /dev/null" >> /var/spool/cron/root
# crontab -l
*/5 * * * * /sbin/ntpdate s2c.time.edu.cn &> /dev/null2、主机名称要与uname -n保持一致，并通过/etc/hosts解析
Master
# hostname Master
# uname -n
Master
# sed -i 's@\(HOSTNAME=\).*@\1Master@g'/etc/sysconfig/network
Slave
# hostname Slave
# uname -n
Slave
# sed -i 's@\(HOSTNAME=\).*@\1Slave@g'/etc/sysconfig/network
node1
# hostname node1.network.com
# uname -n
node3.network.com
# sed -i 's@\(HOSTNAME=\).*@\1node1.network.com@g'/etc/sysconfig/network
node2
# hostname node2.network.com
# uname -n
node2.network.com
# sed -i 's@\(HOSTNAME=\).*@\1node2.network.com@g'/etc/sysconfig/network
node1添加hosts解析
# vim /etc/hosts
# cat /etc/hosts
# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1CentOS5.8 CentOS5 localhost.localdomain localhost
::1localhost6.localdomain6 localhost6
172.16.1.101Master
172.16.1.105Slave
172.16.1.103node1.network.com node1
172.16.1.104node2.network.com node2
拷贝此hosts文件至Slave
# scp /etc/hosts Slave:/etc/
The authenticity of host 'Slave (172.16.1.105)' can't be established.
RSA key fingerprint is 13:42:92:7b:ff:61:d8:f3:7c:97:5f:22:f6:71:b3:24.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'Slave' (RSA) to the list of known hosts.
hosts 100%328 0.3KB/s 00:00
拷贝此hosts文件至node1
# scp /etc/hosts node1:/etc/
The authenticity of host 'node1 (172.16.1.103)' can't be established.
RSA key fingerprint is 1e:87:cd:f0:95:ff:a8:ef:19:bc:c6:e7:0a:87:6b:fa.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'node1,172.16.1.103' (RSA) to the list of known hosts.
root@node1's password:
hosts 100%328 0.3KB/s 00:00
拷贝此hosts文件至node2
# scp /etc/hosts node2:/etc/
The authenticity of host 'node2 (172.16.1.104)' can't be established.
RSA key fingerprint is 1e:87:cd:f0:95:ff:a8:ef:19:bc:c6:e7:0a:87:6b:fa.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'node2,172.16.1.104' (RSA) to the list of known hosts.
root@node2's password:
hosts 100%328 0.3KB/s 00:003、关闭iptables和selinux
Master
# service iptables stop
# vim /etc/sysconfig/selinux
# cat /etc/sysconfig/selinux
# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#enforcing - SELinux security policy is enforced.
#permissive - SELinux prints warnings instead of enforcing.
#disabled - SELinux is fully disabled.
#SELINUX=permissive
SELINUX=disabled
# SELINUXTYPE= type of policy in use. Possible values are:
#targeted - Only targeted network daemons are protected.
#strict - Full SELinux protection.
SELINUXTYPE=targeted
Slave
# service iptables stop
# vim /etc/sysconfig/selinux
# cat /etc/sysconfig/selinux
# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#enforcing - SELinux security policy is enforced.
#permissive - SELinux prints warnings instead of enforcing.
#disabled - SELinux is fully disabled.
#SELINUX=permissive
SELINUX=disabled
# SELINUXTYPE= type of policy in use. Possible values are:
#targeted - Only targeted network daemons are protected.
#strict - Full SELinux protection.
SELINUXTYPE=targeted
node1
# service iptables stop
# vim /etc/sysconfig/selinux
# cat /etc/sysconfig/selinux
# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#enforcing - SELinux security policy is enforced.
#permissive - SELinux prints warnings instead of enforcing.
#disabled - SELinux is fully disabled.
#SELINUX=permissive
SELINUX=disabled
# SELINUXTYPE= type of policy in use. Possible values are:
#targeted - Only targeted network daemons are protected.
#strict - Full SELinux protection.
SELINUXTYPE=targeted
node2
# service iptables stop
# vim /etc/sysconfig/selinux
# cat /etc/sysconfig/selinux
# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#enforcing - SELinux security policy is enforced.
#permissive - SELinux prints warnings instead of enforcing.
#disabled - SELinux is fully disabled.
#SELINUX=permissive
SELINUX=disabled
# SELINUXTYPE= type of policy in use. Possible values are:
#targeted - Only targeted network daemons are protected.
#strict - Full SELinux protection.
SELINUXTYPE=targeted 4、配置node1和node2
首先安装httpd服务
# yum install -y httpd
提供测试页面
# echo "node1.network.com" > /var/www/html/index.html
# cat /var/www/html/index.html
node1.network.com
启动httpd服务
# service httpd start
Starting httpd:
创建一个脚本，用于配置node1
# vim RealServer.sh
# cat RealServer.sh
#!/bin/bash
#
# Script to start LVS DR real server.
# chkconfig: - 90 10
# description: LVS DR real server
#
./etc/rc.d/init.d/functions
VIP=172.16.1.110
host=`/bin/hostname`
case "$1" in
start)
# Start LVS-DR real server on this machine.
/sbin/ifconfig lo down
/sbin/ifconfig lo up
echo 1 > /proc/sys/net/ipv4/conf/eth0/arp_ignore
echo 2 > /proc/sys/net/ipv4/conf/eth0/arp_announce
echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore
echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce
/sbin/ifconfig lo:0 $VIP broadcast $VIP netmask 255.255.255.255 up
/sbin/route add -host $VIP dev lo:0
;;
stop)
# Stop LVS-DR real server loopback device(s).
/sbin/ifconfig lo:0 down
echo 0 > /proc/sys/net/ipv4/conf/eth0/arp_ignore
echo 0 > /proc/sys/net/ipv4/conf/eth0/arp_announce
echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore
echo 0 > /proc/sys/net/ipv4/conf/all/arp_announce
;;
status)
# Status of LVS-DR real server.
islothere=`/sbin/ifconfig lo:0 | grep $VIP`
isrothere=`netstat -rn | grep "lo:0" | grep $VIP`
if [ ! "$islothere" -o ! "isrothere" ];then
# Either the route or the lo:0 device
# not found.
echo "LVS-DR real server Stopped."
else
echo "LVS-DR real server Running."
fi
;;
*)
# Invalid entry.
echo "$0: Usage: $0 {start|status|stop}"
exit 1
;;
esac
给此脚本添加执行权限并执行
# chmod +x RealServer.sh
# ./RealServer.sh start
查看四个内核参数、路由条目以及VIP是否配置上
# cat /proc/sys/net/ipv4/conf/eth0/arp_ignore
1
# cat /proc/sys/net/ipv4/conf/all/arp_ignore
1
# cat /proc/sys/net/ipv4/conf/all/arp_announce
2
# cat /proc/sys/net/ipv4/conf/eth0/arp_announce
2
# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
172.16.1.110 0.0.0.0 255.255.255.255 UH 0 0 0 lo
172.16.1.0 0.0.0.0 255.255.255.0 U 0 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 1002 0 0 eth0
0.0.0.0 172.16.1.1 0.0.0.0 UG 0 0 0 eth0
# ifconfig lo:0
lo:0 Link encap:Local Loopback
inet addr:172.16.1.110Mask:255.255.255.255
UP LOOPBACK RUNNINGMTU:16436Metric:1
node1的配置完毕，node2是一样的，这里就不再演示了
5、Master与Slave安装keepalived与ipvsadm
Master
# wget http://techdata.mirror.gtcomm.net/sysadmin/keepalived/keepalived-1.2.1-5.el5.x86_64.rpm
# yum install --nogpgcheck -y keepalived-1.2.1-5.el5.x86_64.rpm ipvsadm
# scpkeepalived-1.2.1-5.el5.x86_64.rpm Slave:~
keepalived-1.2.1-5.el5.x86_64.rpm 100%163KB 163.4KB/s 00:00
Slave
# yum install --nogpgcheck -y keepalived-1.2.1-5.el5.x86_64.rpm ipvsadm 6、编辑keepalived的主配置文件
# cd /etc/keepalived/
# ls
keepalived.conf
# cp keepalived.conf{,.back}
# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost # 指定通知的邮箱地址
}
notification_email_from root #指定通知邮件时由谁发的
smtp_server 127.0.0.1 # 指定smtp邮件服务器地址
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_instance VI_1 {
state MASTER # 指定为主节点
interface eth0 # 指定接口
virtual_router_id 51 # 指定虚拟路由标识符
priority 100 # 指定优先级，注意，主的一定要比从的优先级数字大
advert_int 1 # 指定同步时间间隔
authentication {
auth_type PASS
auth_pass soysauce # 指定认证密码
}
virtual_ipaddress {
172.16.1.110/16 dev eth0 label eth0:0 # 指定VIP
}
}
virtual_server 172.16.1.110 80 {
delay_loop 6
lb_algo rr # 指定调度算法
lb_kind DR # 指定LVS类型
nat_mask 255.255.0.0 # 指定掩码
#persistence_timeout 50
protocol TCP
real_server 172.16.1.103 80 {
weight 1
HTTP_GET { # 指定健康状态检测方法
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
real_server 172.16.1.104 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
}
将此配置文件拷贝至Slave上
# scp keepalived.conf Slave:/etc/keepalived/
keepalived.conf 100% 1166 1.1KB/s 00:00 7、配置从节点的配置文件
# vim /etc/keepalived/keepalived.conf
# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_instance VI_1 {
state BACKUP # 这里改为BACKUP
interface eth0
virtual_router_id 51
priority 99 # 修改优先级，一定要比主节点小
advert_int 1
authentication {
auth_type PASS
auth_pass soysauce
}
virtual_ipaddress {
172.16.1.110/16 dev eth0 label eth0:0
}
}
virtual_server 172.16.1.110 80 {
delay_loop 6
lb_algo rr
lb_kind DR
nat_mask 255.255.0.0
#persistence_timeout 50
protocol TCP
real_server 172.16.1.103 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
real_server 172.16.1.104 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
} 8、启动keepalived服务，提供ipvs高可用
Master
# service keepalived start
Starting keepalived:
Slave
# service keepalived start
Starting keepalived:
在Master节点上查看ipvs规则是否生效
# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP172.16.1.110:80 rr
-> 172.16.1.104:80 Route 1 0 0
-> 172.16.1.103:80 Route 1 0 0
查看vip地址是否生效
# ip addr show dev eth0
2: eth0:mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:0c:29:fe:82:38 brd ff:ff:ff:ff:ff:ff
inet 172.16.1.101/24 brd 255.255.255.255 scope global eth0
inet 172.16.1.110/16 scope global eth0:0
inet6 fe80::20c:29ff:fefe:8238/64 scope link
valid_lft forever preferred_lft forever 浏览器访问一下
http://s3.运维网.com/wyfs02/M00/79/A6/wKiom1aXR8LA479nAAGLjRnBnKA855.jpg
再刷新一下
http://s3.运维网.com/wyfs02/M00/79/A5/wKioL1aXR_bx34k-AAGKCuIN0Ik052.jpg
可以看到，rr调度算法生效
9、增加Keepalived的维护模式切换功能
要想启用keepalived的维护模式切换功能，只需要在配置文件中定义一个vrrp_script和track_script即可
如
vrrp_script chk_maintainace {
script "[[ -e /etc/keepalived/down ]] && exit 1 || exit 0"
interval 1
weight -2
}
track_script {
chk_maintainace
}
vrrp_script放在vrrp实例之外
track_script放在vrrp实例之内
配置文件样例
# cat keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_maintainace { # 定义vrrp_script脚本
script "[[ -e /etc/keepalived/down ]] && exit 1 || exit 0"
interval 1
weight -2
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass soysauce
}
virtual_ipaddress {
172.16.1.110/16 dev eth0 label eth0:0
}
track_script { # 定义track_script脚本
chk_maintainace
}
}
virtual_server 172.16.1.110 80 {
delay_loop 6
lb_algo rr
lb_kind DR
nat_mask 255.255.0.0
#persistence_timeout 50
protocol TCP
real_server 172.16.1.103 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
real_server 172.16.1.104 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
}
修改完配置文件之后，手动同步至从节点，并修改从节点上配置文件state为BACKUP,priority为99
修改完成之后，重启两个节点上的keepalived服务
先查看Master上的vip是已经生效的
# ip addr show dev eth0
2: eth0:mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:0c:29:fe:82:38 brd ff:ff:ff:ff:ff:ff
inet 172.16.1.101/24 brd 255.255.255.255 scope global eth0
inet 172.16.1.110/16 scope global eth0:0
inet6 fe80::20c:29ff:fefe:8238/64 scope link
valid_lft forever preferred_lft forever
此时创建一个空文件down
# touch down
再次查看ip地址，发现已经转移至从节点了
# ip addr show dev eth0
2: eth0:mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:0c:29:fe:82:38 brd ff:ff:ff:ff:ff:ff
inet 172.16.1.101/24 brd 255.255.255.255 scope global eth0
inet6 fe80::20c:29ff:fefe:8238/64 scope link
valid_lft forever preferred_lft forever
再删除down文件并查看vip是否转移回来
# rm -f down
# ip addr show dev eth0
2: eth0:mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:0c:29:fe:82:38 brd ff:ff:ff:ff:ff:ff
inet 172.16.1.101/24 brd 255.255.255.255 scope global eth0
inet 172.16.1.110/16 scope global eth0:0
inet6 fe80::20c:29ff:fefe:8238/64 scope link
valid_lft forever preferred_lft forever
因为Master优先级为100，Slave优先级为99，所以当Master上线时，资源会自动转移回来 10、增加Keepalived的主从切换邮件通知功能
提供一个脚本来实现
# cd /etc/keepalived/
# vim notify.sh
# cat notify.sh
#!/bin/bash
# Author: MageEdu
# description: An example of notify script
#
vip=172.16.1.110
contact='root@localhost'
notify() {
mailsubject="`hostname` to be $1: $vip floating"
mailbody="`date '+%F %H:%M:%S'`: vrrp transition, `hostname` changed to be $1"
echo $mailbody | mail -s "$mailsubject" $contact
}
case "$1" in
master)
notify master
exit 0
;;
backup)
notify backup
exit 0
;;
fault)
notify fault
exit 0
;;
*)
echo 'Usage: `basename $0` {master|backup|fault}'
exit 1
;;
esac
# chmod +x notify.sh
添加在配置文件中
# vim keepalived.conf
# cat keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_maintainace {
script "[[ -e /etc/keepalived/down ]] && exit 1 || exit 0"
interval 1
weight -2
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass soysauce
}
virtual_ipaddress {
172.16.1.110/16 dev eth0 label eth0:0
}
track_script {
chk_maintainace
}
notify_master "/etc/keepalived/notify.sh master" # 增加这三行
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
virtual_server 172.16.1.110 80 {
delay_loop 6
lb_algo rr
lb_kind DR
nat_mask 255.255.0.0
#persistence_timeout 50
protocol TCP
real_server 172.16.1.103 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
real_server 172.16.1.104 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 2
nb_get_retry 3
delay_before_retry 1
}
}
}
然后将notif.sh脚本复制至Slave的/etc/keepalived目录下，增加执行权限
然后在其配置文件中增加三行，增加完成之后两个节点重启keepalived服务即可 11、增加对nginx的高可用
通过一个vrrp_script和track_script来实现
如
# vim keepalived.conf
# cat keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
#vrrp_script chk_maintainace {
# script "[[ -e /etc/keepalived/down ]] && exit 1 || exit 0"
# interval 1
# weight -2
#}
vrrp_script chk_nginx {
script "killall -0 nginx"
interval 1
weight -2
fail 2
rise 1
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass soysauce
}
virtual_ipaddress {
172.16.1.110/16 dev eth0 label eth0:0
}
track_script {
# chk_maintainace
chk_nginx
}
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
#virtual_server 172.16.1.110 80 {
# delay_loop 6
# lb_algo rr
# lb_kind DR
# nat_mask 255.255.0.0
# #persistence_timeout 50
# protocol TCP
# real_server 172.16.1.103 80 {
# weight 1
# HTTP_GET {
# url {
# path /
# status_code 200
# }
# connect_timeout 2
# nb_get_retry 3
# delay_before_retry 1
# }
# }
# real_server 172.16.1.104 80 {
# weight 1
# HTTP_GET {
# url {
# path /
# status_code 200
# }
# connect_timeout 2
# nb_get_retry 3
# delay_before_retry 1
# }
# }
#}
然后修改notify.sh脚本
# vim notify.sh
# cat notify.sh
#!/bin/bash
# Author: MageEdu
# description: An example of notify script
#
vip=172.16.1.110
contact='root@localhost'
notify() {
mailsubject="`hostname` to be $1: $vip floating"
mailbody="`date '+%F %H:%M:%S'`: vrrp transition, `hostname` changed to be $1"
echo $mailbody | mail -s "$mailsubject" $contact
}
case "$1" in
master)
notify master
/etc/rc.d/init.d/nginx start
exit 0
;;
backup)
notify backup
/etc/rc.d/init.d/nginx restart
exit 0
;;
fault)
notify fault
/etc/rc.d/init.d/nginx stop
exit 0
;;
*)
echo 'Usage: `basename $0` {master|backup|fault}'
exit 1
;;
esac
修改完成之后，手动同步配置文件和notify.sh至从节点，并修改从节点上配置文件state和priority
修改完成之后，重启两个节点上的keepalived服务 12、实现基于多虚拟路由的master/master模型
配置两个虚拟路由即可，双方互为主从
# vim keepalived.conf
# cat keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
#vrrp_script chk_maintainace {
# script "[[ -e /etc/keepalived/down ]] && exit 1 || exit 0"
# interval 1
# weight -2
#}
vrrp_script chk_nginx {
script "killall -0 nginx"
interval 1
weight -3
fail 2
rise 1
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass soysauce
}
virtual_ipaddress {
172.16.1.110/16 dev eth0 label eth0:0
}
track_script {
# chk_maintainace
chk_nginx
}
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
vrrp_instance VI_2 {
state BACKUP
interface eth0
virtual_router_id 52
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass network
}
virtual_ipaddress {
172.16.1.120/16 dev eth0 label eth0:1
}
track_script {
# chk_maintainace
chk_nginx
}
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
#virtual_server 172.16.1.110 80 {
# delay_loop 6
# lb_algo rr
# lb_kind DR
# nat_mask 255.255.0.0
# #persistence_timeout 50
# protocol TCP
# real_server 172.16.1.103 80 {
# weight 1
# HTTP_GET {
# url {
# path /
# status_code 200
# }
# connect_timeout 2
# nb_get_retry 3
# delay_before_retry 1
# }
# }
# real_server 172.16.1.104 80 {
# weight 1
# HTTP_GET {
# url {
# path /
# status_code 200
# }
# connect_timeout 2
# nb_get_retry 3
# delay_before_retry 1
# }
# }
#}
再来修改从节点的配置文件
# vim keepalived.conf
You have new mail in /var/spool/mail/root
# cat keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
#vrrp_script chk_maintainace {
# script "[[ -e /etc/keepalived/down ]] && exit 1 || exit 0"
# interval 1
# weight -2
#}
vrrp_script chk_nginx {
script "killall -0 nginx"
interval 1
weight -3
fail 2
rise 1
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 51
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass soysauce
}
virtual_ipaddress {
172.16.1.110/16 dev eth0 label eth0:0
}
track_script {
# chk_maintainace
chk_nginx
}
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
vrrp_instance VI_2 {
state MASTER
interface eth0
virtual_router_id 52
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass network
}
virtual_ipaddress {
172.16.1.120/16 dev eth0 label eth0:1
}
track_script {
# chk_maintainace
chk_nginx
}
notify_master "/etc/keepalived/notify.sh master"
notify_backup "/etc/keepalived/notify.sh backup"
notify_fault "/etc/keepalived/notify.sh fault"
}
#virtual_server 172.16.1.110 80 {
# delay_loop 6
# lb_algo rr
# lb_kind DR
# nat_mask 255.255.0.0
# #persistence_timeout 50
# protocol TCP
# real_server 172.16.1.103 80 {
# weight 1
# HTTP_GET {
# url {
# path /
# status_code 200
# }
# connect_timeout 2
# nb_get_retry 3
# delay_before_retry 1
# }
# }
# real_server 172.16.1.104 80 {
# weight 1
# HTTP_GET {
# url {
# path /
# status_code 200
# }
# connect_timeout 2
# nb_get_retry 3
# delay_before_retry 1
# }
# }
#}
重启两节点的keepalived服务
# service keepalived restart
Stopping keepalived:
Starting keepalived:
# service keepalived restart
Stopping keepalived:
Starting keepalived:
此时查看两个节点的vip是否生效
# ip addr show dev eth0
2: eth0:mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:0c:29:fe:82:38 brd ff:ff:ff:ff:ff:ff
inet 172.16.1.101/24 brd 255.255.255.255 scope global eth0
inet 172.16.1.110/16 scope global eth0:0
inet6 fe80::20c:29ff:fefe:8238/64 scope link
valid_lft forever preferred_lft forever
# ip addr show dev eth0
2: eth0:mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:0c:29:66:34:d1 brd ff:ff:ff:ff:ff:ff
inet 172.16.1.105/24 brd 255.255.255.255 scope global eth0
inet 172.16.1.120/16 scope global eth0:1
inet6 fe80::20c:29ff:fe66:34d1/64 scope link
valid_lft forever preferred_lft forever
此时使某一个节点downdiao
# service keepalived stop
Stopping keepalived:
可以发现down掉的节点的vip转移至另一个节点，另一个节点有了两个vip
# ip addr show dev eth0
2: eth0:mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:0c:29:fe:82:38 brd ff:ff:ff:ff:ff:ff
inet 172.16.1.101/24 brd 255.255.255.255 scope global eth0
inet6 fe80::20c:29ff:fefe:8238/64 scope link
valid_lft forever preferred_lft forever
# ip addr show dev eth0
2: eth0:mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:0c:29:66:34:d1 brd ff:ff:ff:ff:ff:ff
inet 172.16.1.105/24 brd 255.255.255.255 scope global eth0
inet 172.16.1.120/16 scope global eth0:1
inet 172.16.1.110/16 scope global secondary eth0:0
inet6 fe80::20c:29ff:fe66:34d1/64 scope link
valid_lft forever preferred_lft forever
再让down掉的那个节点重新上线
# service keepalived start
Starting keepalived:
# ip addr show dev eth0
2: eth0:mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:0c:29:66:34:d1 brd ff:ff:ff:ff:ff:ff
inet 172.16.1.105/24 brd 255.255.255.255 scope global eth0
inet 172.16.1.120/16 scope global eth0:1
inet6 fe80::20c:29ff:fe66:34d1/64 scope link
valid_lft forever preferred_lft forever
可以看到地址又转移回来了
# ip addr show dev eth0
2: eth0:mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:0c:29:fe:82:38 brd ff:ff:ff:ff:ff:ff
inet 172.16.1.101/24 brd 255.255.255.255 scope global eth0
inet 172.16.1.110/16 scope global eth0:0
inet6 fe80::20c:29ff:fefe:8238/64 scope link
valid_lft forever preferred_lft forever
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