Keepalived实现LVS高可用

6.1 Keepalived+LVS集群介绍

  • Keepalived和LVS共同构建了一个高效的负载均衡和高可用性解决方案：LVS作为负载均衡器，负责在集群中的多个服务器间分配流量，以其高性能和可扩展性确保应用程序能够处理大量的并发请求；而Keepalived则作为高可用性保证，通过VRRP协议监控LVS服务的状态并在主服务器发生故障时自动进行故障转移，确保服务的持续可用性和无感知切换。这种结合利用了两者的优势，为关键的网络服务提供了一个稳定、可靠且高效的运行环境。

image-20240506100440332

机器名称IP地址子网掩码说明
Keepalived-01192.168.110.31255.255.255.0负载均衡+高可用
Keepalived-02192.168.110.32255.255.255.0负载均衡+高可用
RS1192.168.110.33255.255.255.0真实服务器1
RS2192.168.110.34255.255.255.0真实服务器2
Client192.168.110.35255.255.255.0客户端

6.2 后端RS配置

  • 配置系统服务脚本

[root@LVS-RS1 ~]# vim /etc/init.d/LVS_RS
#!/bin/bash
​
# Startup script to handle the initialisation of LVS
# chkconfig: - 28 72
# description: Initialise the Linux Virtual Server for DR
# Provides: ipvsadm
# Required-Start: $local_fs $network $named
# Required-Stop: $local_fs $remote_fs $network
# Short-Description: Initialise the Linux Virtual Server
# Description: The Linux Virtual Server is a highly scalable and highly
# available server built on a cluster of real servers, with the load
# balancer running on Linux.
​
LOCK=/var/lock/ipvsadm.lock
VIP=192.168.110.10
​
. /etc/rc.d/init.d/functions
​
start() {PID=`ifconfig | grep lo:20 | wc -l`if [ $PID -ne 0 ]; thenecho "The LVS-DR-RIP Server is already running !"else/sbin/ifconfig lo:20 $VIP netmask 255.255.255.255 broadcast $VIP up/sbin/route add -host $VIP dev lo:20echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignoreecho "2" >/proc/sys/net/ipv4/conf/lo/arp_announceecho "1" >/proc/sys/net/ipv4/conf/all/arp_ignoreecho "2" >/proc/sys/net/ipv4/conf/all/arp_announce/bin/touch $LOCKecho "starting LVS-DR-RIP server is ok !"fi
}
​
stop() {/sbin/route del -host $VIP dev lo:20/sbin/ifconfig lo:20 down >/dev/nullecho "0" >/proc/sys/net/ipv4/conf/lo/arp_ignoreecho "0" >/proc/sys/net/ipv4/conf/lo/arp_announceecho "0" >/proc/sys/net/ipv4/conf/all/arp_ignoreecho "0" >/proc/sys/net/ipv4/conf/all/arp_announcerm -rf $LOCKecho "stopping LVS-DR-RIP server is ok !"
}
​
status() {if [ -e $LOCK ]; thenecho "The LVS-DR-RIP Server is already running !"elseecho "The LVS-DR-RIP Server is not running !"fi
}
​
case "$1" instart)start;;stop)stop;;restart)stopstart;;status)status;;*)echo "Usage: $1 {start|stop|restart|status}"exit 1
esac
exit 0
​
[root@LVS-RS1 ~]# chmod +x /etc/init.d/LVS_RS 
[root@LVS-RS1 ~]# chkconfig --add LVS_RS 
[root@LVS-RS1 ~]# systemctl start LVS_RS.service 
[root@LVS-RS1 ~]# scp /etc/init.d/LVS_RS 192.168.110.34:/etc/init.d/   #发给另一台RS
​
[root@LVS-RS2 ~]# chmod +x /etc/init.d/LVS_RS 
[root@LVS-RS2 ~]# chkconfig --add LVS_RS 
[root@LVS-RS2 ~]# systemctl start LVS_RS.service

6.3 Keepalived配置

6.3.1 基于TCP的健康检测

6.3.1.1 Keepalived-01配置
[root@Keepalived-01 ~]# cp /etc/keepalived/keepalived.conf{,.bak}
[root@Keepalived-01 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
​
global_defs {router_id LVS_node1
}
​
vrrp_instance LVS {state MASTERinterface ens160virtual_router_id 51priority 100advert_int 1authentication {auth_type PASSauth_pass 1111}virtual_ipaddress {192.168.110.10}
}
​
virtual_server 192.168.110.10 80 {delay_loop 6  lb_algo rrlb_kind DRprotocol TCP
​real_server 192.168.110.33 80 {weight 1TCP_CHECK {connect_timeout 3retry 3delay_before_retry 3connect_port 80}}real_server 192.168.110.34 80 {weight 1TCP_CHECK {connect_timeout 3retry 3delay_before_retry 3connect_port 80}}
}
​
​
[root@Keepalived-01 ~]# systemctl start keepalived.service
[root@Keepalived-01 ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags-> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.110.10:80 rr-> 192.168.110.33:80            Route   1      0          0         -> 192.168.110.34:80            Route   1      0          0
6.3.1.2 Keepalived-02配置
[root@Keepalived-02 ~]# cp /etc/keepalived/keepalived.conf{,.bak}
[root@Keepalived-02 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
​
global_defs {router_id LVS_node2
}
​
vrrp_instance LVS {state MASTERinterface ens160virtual_router_id 51priority 80advert_int 1authentication {auth_type PASSauth_pass 1111}virtual_ipaddress {192.168.110.10}
}
​
virtual_server 192.168.110.10 80 {delay_loop 6  lb_algo rrlb_kind DRprotocol TCP
​real_server 192.168.110.33 80 {weight 1TCP_CHECK {connect_timeout 3retry 3delay_before_retry 3connect_port 80}}real_server 192.168.110.34 80 {weight 1TCP_CHECK {connect_timeout 3retry 3delay_before_retry 3connect_port 80}}
}
​
[root@Keepalived-02 ~]# systemctl start keepalived.service
[root@Keepalived-02 ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags-> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.110.10:80 rr-> 192.168.110.33:80            Route   1      0          0         -> 192.168.110.34:80            Route   1      0          0        
6.3.1.3 访问测试
[root@Client ~]# for ((i=1;i<=6;i++)); do curl http://192.168.110.10; done
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.33  Host=LVS-RS1
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.33  Host=LVS-RS1
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.33  Host=LVS-RS1
6.3.1.4 模拟故障转移
[root@Keepalived-01 ~]# systemctl stop keepalived.service
​
[root@Keepalived-02 ~]# ip address show ens160   #VIP漂移到Keepalived-02
2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000link/ether 00:0c:29:b0:0d:30 brd ff:ff:ff:ff:ff:ffaltname enp3s0inet 192.168.110.32/24 brd 192.168.110.255 scope global noprefixroute ens160valid_lft forever preferred_lft foreverinet 192.168.110.10/32 scope global ens160valid_lft forever preferred_lft foreverinet6 fe80::20c:29ff:feb0:d30/64 scope link noprefixroute valid_lft forever preferred_lft forever
​
[root@Client ~]# for ((i=1;i<=6;i++)); do curl http://192.168.110.10; done  #访问正常
This is LVS test IP=192.168.110.33  Host=LVS-RS1
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.33  Host=LVS-RS1
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.33  Host=LVS-RS1
This is LVS test IP=192.168.110.34  Host=LVS-RS2
​
[root@Keepalived-01 ~]# systemctl start keepalived.service
[root@Keepalived-01 ~]# ip address show ens160     #恢复后回来
2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000link/ether 00:0c:29:d1:a9:eb brd ff:ff:ff:ff:ff:ffaltname enp3s0inet 192.168.110.31/24 brd 192.168.110.255 scope global noprefixroute ens160valid_lft forever preferred_lft foreverinet 192.168.110.10/32 scope global ens160valid_lft forever preferred_lft foreverinet6 fe80::20c:29ff:fed1:a9eb/64 scope link noprefixroute valid_lft forever preferred_lft forever
6.3.1.5 后端服务器故障
[root@LVS-RS1 ~]# systemctl stop nginx.service
​
[root@Keepalived-02 ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags-> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.110.10:80 rr-> 192.168.110.34:80            Route   1      0          9   [root@Client ~]# for ((i=1;i<=6;i++)); do curl http://192.168.110.10; done    #访问正常
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.34  Host=LVS-RS2

6.3.2 基于HTTP的健康检测

6.3.2.1 生成远程网页的MD5哈希值

  • genhash 是一个命令行工具，用于生成远程网页的MD5哈希值。它可以用于监控HTTP和HTTPS服务，特别是在Keepalived配置中，用于健康检查。genhash 可以通过HTTP或HTTPS连接到网页，并生成页面数据的MD5哈希值，该哈希值可以在Keepalived配置文件中使用。

[root@Keepalived-01 ~]# genhash -s 192.168.110.33 -p 80 -u /index.html
MD5SUM = fd0508d1ccc6c66c14977e54ffc7faef
​
[root@Keepalived-01 ~]# genhash -s 192.168.110.34 -p 80 -u /index.html
MD5SUM = 0632aaa5fb77608b1a4736d47aacb62c
​
[root@Keepalived-02 ~]# genhash -s 192.168.110.33 -p 80 -u /index.html
MD5SUM = fd0508d1ccc6c66c14977e54ffc7faef
​
[root@Keepalived-02 ~]# genhash -s 192.168.110.34 -p 80 -u /index.html
MD5SUM = 0632aaa5fb77608b1a4736d47aacb62c
6.3.2.2 Keepalived-01配置
[root@Keepalived-01 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
​
global_defs {router_id LVS_node1
}
​
vrrp_instance LVS {state MASTERinterface ens160virtual_router_id 51priority 100advert_int 1authentication {auth_type PASSauth_pass 1111}virtual_ipaddress {192.168.110.10}
}
virtual_server 192.168.110.10 80 {delay_loop 6  lb_algo rrlb_kind DRprotocol TCP
​real_server 192.168.110.33 80 {weight 1
​HTTP_GET {url {path /index.htmldigest fd0508d1ccc6c66c14977e54ffc7faef}connect_timeout 3nb_get_retry 3delay_before_retry 3}}real_server 192.168.110.34 80 {weight 1HTTP_GET {url {path /index.htmldigest 0632aaa5fb77608b1a4736d47aacb62c
​}connect_timeout 3nb_get_retry 3delay_before_retry 3}}
}
​
[root@Keepalived-01 ~]# systemctl start keepalived.service
[root@Keepalived-01 ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags-> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.110.10:80 rr-> 192.168.110.33:80            Route   1      0          0         -> 192.168.110.34:80            Route   1      0          0    
6.3.2.3 Keepalived-02配置
[root@Keepalived-02 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
​
global_defs {router_id LVS_node2
}
​
vrrp_instance LVS {state MASTERinterface ens160virtual_router_id 51priority 80advert_int 1authentication {auth_type PASSauth_pass 1111}virtual_ipaddress {192.168.110.10}
}
virtual_server 192.168.110.10 80 {delay_loop 6  lb_algo rrlb_kind DRprotocol TCP
​real_server 192.168.110.34 80 {weight 1
​HTTP_GET {url {path /index.htmldigest fd0508d1ccc6c66c14977e54ffc7faef}connect_timeout 3nb_get_retry 3delay_before_retry 3}}real_server 192.168.110.34 80 {weight 1HTTP_GET {url {path /index.htmldigest 0632aaa5fb77608b1a4736d47aacb62c
​}connect_timeout 3nb_get_retry 3delay_before_retry 3}}
}
​
​
[root@Keepalived-02 ~]# systemctl start keepalived.service
[root@Keepalived-02 ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags-> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.110.10:80 rr-> 192.168.110.33:80            Route   1      0          0         -> 192.168.110.34:80            Route   1      0          0    
6.3.2.4 访问测试
[root@Client ~]# for ((i=1;i<=6;i++)); do curl http://192.168.110.10; done
This is LVS test IP=192.168.110.33  Host=LVS-RS1
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.33  Host=LVS-RS1
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.33  Host=LVS-RS1
This is LVS test IP=192.168.110.34  Host=LVS-RS2
6.3.2.5 模拟故障转移
[root@Keepalived-01 ~]# systemctl stop keepalived.service
​
[root@Keepalived-02 ~]# ip address show ens160   #VIP漂移到Keepalived-02
2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000link/ether 00:0c:29:b0:0d:30 brd ff:ff:ff:ff:ff:ffaltname enp3s0inet 192.168.110.32/24 brd 192.168.110.255 scope global noprefixroute ens160valid_lft forever preferred_lft foreverinet 192.168.110.10/32 scope global ens160valid_lft forever preferred_lft foreverinet6 fe80::20c:29ff:feb0:d30/64 scope link noprefixroute valid_lft forever preferred_lft forever
​
[root@Client ~]# for ((i=1;i<=6;i++)); do curl http://192.168.110.10; done  #访问正常
This is LVS test IP=192.168.110.33  Host=LVS-RS1
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.33  Host=LVS-RS1
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.33  Host=LVS-RS1
This is LVS test IP=192.168.110.34  Host=LVS-RS2
​
[root@Keepalived-01 ~]# systemctl start keepalived.service
[root@Keepalived-01 ~]# ip address show ens160     #恢复后回来
2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000link/ether 00:0c:29:d1:a9:eb brd ff:ff:ff:ff:ff:ffaltname enp3s0inet 192.168.110.31/24 brd 192.168.110.255 scope global noprefixroute ens160valid_lft forever preferred_lft foreverinet 192.168.110.10/32 scope global ens160valid_lft forever preferred_lft foreverinet6 fe80::20c:29ff:fed1:a9eb/64 scope link noprefixroute valid_lft forever preferred_lft forever
6.3.2.6 后端服务器故障
[root@LVS-RS1 ~]# systemctl stop nginx.service
​
[root@Keepalived-01 ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags-> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.110.10:80 rr-> 192.168.110.34:80            Route   1      0          6  [root@Client ~]# for ((i=1;i<=6;i++)); do curl http://192.168.110.10; done
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.34  Host=LVS-RS2

6.3.3 Keepalived健康检查（MISC方式）

6.3.3.1 编写健康脚本
[root@Keepalived-01 ~]# vim /etc/keepalived/chk_web.sh
#!/bin/bash# 检查传入的参数数量是否正确
if [ $# -ne 2 ]; thenecho "Error, Parameter error"exit 1
else# 使用 nmap 进行端口扫描，获取端口状态n=$(nmap -Pn -p$2 -sS -vv $1 | grep "^$2" | awk '{print $2}')
​# 判断端口是否开放if [ "$n" = "open" ]; thenexit 0elseexit 1fi
fi
​
[root@Keepalived-01 ~]# chmod +x /etc/keepalived/chk_web.sh 
[root@Keepalived-01 ~]# scp /etc/keepalived/chk_web.sh 192.168.110.32:/etc/keepalived/
6.3.3.2 keepalived-01配置
[root@Keepalived-01 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
​
global_defs {router_id LVS_node1
}
​
vrrp_instance LVS {state MASTERinterface ens160virtual_router_id 51priority 100advert_int 1authentication {auth_type PASSauth_pass 1111}virtual_ipaddress {192.168.110.10}
}
​
virtual_server  192.168.110.10  80 {delay_loop  6lb_algo rrlb_kind DRprotocol TCP
​real_server  192.168.110.33  80 {weight  1MISC_CHECK {misc_path "/etc/keepalived/chk_web.sh  192.168.110.33  80"misc_timeout  3}}
​real_server  192.168.110.34  80 {weight  1MISC_CHECK {misc_path "/etc/keepalived/chk_web.sh  192.168.110.34  80"misc_timeout  3}}
}
​
​
[root@Keepalived-01 ~]# systemctl start keepalived.service
[root@Keepalived-01 ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags-> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.110.10:80 rr-> 192.168.110.33:80            Route   1      0          0         -> 192.168.110.34:80            Route   1      0          0  
6.3.3.3 keepalived-02配置
[root@Keepalived-02 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
​
global_defs {router_id LVS_node2
}
​
vrrp_instance LVS {state MASTERinterface ens160virtual_router_id 51priority 80advert_int 1authentication {auth_type PASSauth_pass 1111}virtual_ipaddress {192.168.110.10}
}
​
virtual_server  192.168.110.10  80 {delay_loop  6lb_algo rrlb_kind DRprotocol TCP
​real_server  192.168.110.33  80 {weight  1MISC_CHECK {misc_path "/etc/keepalived/chk_web.sh  192.168.110.33  80"misc_timeout  3}}
​real_server  192.168.110.34  80 {weight  1MISC_CHECK {misc_path "/etc/keepalived/chk_web.sh  192.168.110.34  80"misc_timeout  3}}
}
​
[root@Keepalived-02 ~]# systemctl start keepalived.service
6.3.3.4 访问测试
[root@Client ~]# for ((i=1;i<=6;i++)); do curl http://192.168.110.10; done
This is LVS test IP=192.168.110.33  Host=LVS-RS1
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.33  Host=LVS-RS1
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.33  Host=LVS-RS1
This is LVS test IP=192.168.110.34  Host=LVS-RS2
6.3.3.5 模拟故障转移
[root@Keepalived-01 ~]# systemctl stop keepalived.service
​
[root@Keepalived-02 ~]# ip address show ens160   #VIP漂移到Keepalived-02
2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000link/ether 00:0c:29:b0:0d:30 brd ff:ff:ff:ff:ff:ffaltname enp3s0inet 192.168.110.32/24 brd 192.168.110.255 scope global noprefixroute ens160valid_lft forever preferred_lft foreverinet 192.168.110.10/32 scope global ens160valid_lft forever preferred_lft foreverinet6 fe80::20c:29ff:feb0:d30/64 scope link noprefixroute valid_lft forever preferred_lft forever
​
[root@Client ~]# for ((i=1;i<=6;i++)); do curl http://192.168.110.10; done  #访问正常
This is LVS test IP=192.168.110.33  Host=LVS-RS1
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.33  Host=LVS-RS1
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.33  Host=LVS-RS1
This is LVS test IP=192.168.110.34  Host=LVS-RS2
​
[root@Keepalived-01 ~]# systemctl start keepalived.service
[root@Keepalived-01 ~]# ip address show ens160     #恢复后回来
2: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000link/ether 00:0c:29:d1:a9:eb brd ff:ff:ff:ff:ff:ffaltname enp3s0inet 192.168.110.31/24 brd 192.168.110.255 scope global noprefixroute ens160valid_lft forever preferred_lft foreverinet 192.168.110.10/32 scope global ens160valid_lft forever preferred_lft foreverinet6 fe80::20c:29ff:fed1:a9eb/64 scope link noprefixroute valid_lft forever preferred_lft forever
6.3.3.6 后端服务器故障
[root@LVS-RS1 ~]# systemctl stop nginx.service
​
[root@Keepalived-01 ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags-> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.110.10:80 rr-> 192.168.110.34:80            Route   1      0          6  [root@Client ~]# for ((i=1;i<=6;i++)); do curl http://192.168.110.10; done
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.34  Host=LVS-RS2
This is LVS test IP=192.168.110.34  Host=LVS-RS2

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