主机:192.168.111.51
备机:192.168.111.52
LVS VIP: 192.168.111.50

1、基础软件包
yum -y install gcc gcc-c++ make popt popt-devel libnl libnl-devel popt-static openssl-devel kernel-devel

建立一个内核信息的符号链接,如下:
ln -s /usr/src/kernels/3.10.0-514.el7.x86_64 /usr/src/linux

2、安装LVS软件

yum -y install ipvsadm
ipvsadm -v
ipvsadm v1.27 2008/5/15 (compiled with popt and IPVS v1.2.1)

3、安装keepalived软件

yum install keepalived
keepalived -v
Keepalived v1.2.13 (05/25,2017)

以下是在安装keepalived时的依赖关系:
Installed:
keepalived.x86_64 0:1.2.13-9.el7_3
Dependency Installed:
lm_sensors-libs.x86_64 0:3.4.0-4.20160601gitf9185e5.el7 net-snmp-agent-libs.x86_64 1:5.7.2-24.el7_3.2 net-snmp-libs.x86_64 1:5.7.2-24.el7_3.2

4、系统防火墙配置
修改iptables配置,在主机上放开备机进来的流量,在备机也做相似设置:

firewall-cmd --direct --permanent --add-rule ipv4 filter INPUT 0 --in-interface enp0s3 --destination 224.0.0.18 --protocol vrrp -j ACCEPT
firewall-cmd --reload

5、配置/etc/keepalived/keepalived.conf文件
注:在备机上,该配置文件仅有router_id和priority的值不同。其它值均一致。

以下为主机上的配置举例:

global_defs {
   notification_email {
     #system@hongshutech.com
   }
   notification_email_from lvs@baiwutong.com
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id LVS_51
}

vrrp_instance VI_1 {
    state BACKUP
    nopreempt
    interface enp0s3
    virtual_router_id 50
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1207
    }
    virtual_ipaddress {
        192.168.111.50
    }
}

virtual_server 192.168.111.50 8888 {
    delay_loop 6
    lb_algo wrr
    lb_kind DR
    #persistence_timeout 2
    protocol TCP

     real_server 192.168.111.61 8888 {
     weight 100
     TCP_CHECK {
         connect_timeout 3
         nb_get_retry 3
         delay_before_retry 3
         connect_port 8888
        }
    }
     real_server 192.168.111.62 8888 {
     weight 100
     TCP_CHECK {
         connect_timeout 3
         nb_get_retry 3
         delay_before_retry 3
         connect_port 8888
        }
    } 
}


virtual_server 192.168.111.50 8000 {
    delay_loop 6
    lb_algo wrr
    lb_kind DR
    #persistence_timeout 2
    protocol TCP

     real_server 192.168.111.61 8000 {
     weight 100
     TCP_CHECK {
         connect_timeout 3
         nb_get_retry 3
         delay_before_retry 3
         connect_port 8000
        }
    }
     real_server 192.168.111.62 8000 {
     weight 100
     TCP_CHECK {
         connect_timeout 3
         nb_get_retry 3
         delay_before_retry 3
         connect_port 8000

        }
    }
   
}

启动keepalived服务

# systemctl start keepalived

查看keepalived服务状态

# systemctl status keepalived

设置为随系统自启动:

# systemctl enable keepalived

查看系统网卡VIP是否已经生效:

# ip a

抓包观察是否有主机定时发出的VRRP包。

# tcpdump -p vrrp -n
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on enp0s3, link-type EN10MB (Ethernet), capture size 65535 bytes
10:16:13.375399 IP 192.168.111.51 > 224.0.0.18: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
10:16:14.376542 IP 192.168.111.51 > 224.0.0.18: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
10:16:15.377596 IP 192.168.111.51 > 224.0.0.18: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20
10:16:16.378590 IP 192.168.111.51 > 224.0.0.18: VRRPv2, Advertisement, vrid 50, prio 100, authtype simple, intvl 1s, length 20

对keepalived的主备切换、VIP地址漂移进行测试。

# systemctl stop keepalived
# systemctl start keepalived

注:为减少服务自动抢占对业务的影响,LVS服务是配置为运行在非抢占模式下。

6、负载均衡后端应用主机的配置
使用DR模式时,在各个提供后端服务的应用主机上传脚本lvs_real_server.sh至/usr/local/src下并设置:

chmod 700 /usr/local/src/lvs_real_server.sh
echo "/usr/local/src/lvs_real_server.sh start" >> /etc/rc.d/rc.local
/usr/local/src/lvs_real_server.sh  start

以下为lvs_real_server.sh的内容,注意要更新VIP参配置:

vi  lvs_real_server.sh
#!/bin/bash
VIP=192.168.111.50
. /etc/rc.d/init.d/functions
case "$1" in
start)
        ifconfig lo:0 $VIP netmask 255.255.255.255 broadcast $VIP
        route add -host $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 "Real Server Start OK"
        ;;
stop)
        ifconfig lo:0 down
        route del $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 "Real Server Stoped"
        ;;
*)
        echo "Usage: $0 {start|stop}"
        exit 1
esac
exit 0

7、测试后端负载均衡服务的方法
在完成LVS部署后,后端提供服务的应用可能还没有上线。这时需要预先测试LVS的负载均衡功能是否正常。方法是使用以下命令,在每个后端节点上临时启动一个http server,服务端口设置为与LVS负载均衡服务相对应的端口号即可。使用后,停掉该命令即可。

python -m SimpleHTTPServer 8888

Serving HTTP on 0.0.0.0 port 8888...

Last modification:May 10th, 2019 at 09:38 am
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