LVS+Keepalived实现高可用和负载均衡

一、实验环境：

[root@a ~]# cat /etc/redhat-release 
CentOS Linux release 7.7.1908 (Core)

[root@a ~]# uname -a
Linux a 3.10.0-1062.el7.x86_64 #1 SMP Wed Aug 7 18:08:02 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

IP分配：
lvs：10.10.10.11
keepalived：10.10.10.14
web1：10.10.10.12
web2：10.10.10.13
vip：10.10.10.100

二、实验目的：

lvs调度器宕机或者web服务器宕机不影响业务的进行

三、实验原理：

1.客户端向LVS的VIP发送请求，源IP和目的IP分别为CIP和VIP，源MAC地址和目的MAC分别为CMAC和DMAC
2.当LVS收到请求后通过调度选出一个realserver来响应请求将源请求中的MAC地址该为自己的MAC地址目的地址改为realserver的MAC地址，此时源MAC和目的MAC分别为DMAC和RMAC,然后将报文送往交换机，交换机收报文后根据目的MAC地址将请求转发至后端Realserver
3.Realserver发现请求报文中的MAC地址是自己就会将报文接收并处理，处理完请求报文后将响应报文通过lo接口送给eth0网卡直接发送给客户端。 注意:需要设置lo接口的VIP不能响应本地网络内的arp请求。

四、实验部分：

（1）构建LVS-DR模式

1、关闭网卡守护进程(all)
systemctl stop NetworkManager && systemctl disable NetworkManager.service

2、开启网卡子接口
配置VIP
[root@a ~]# cd /etc/sysconfig/network-scripts/
[root@a network-scripts]# cp -a ifcfg-ens32 ifcfg-ens32:0
[root@a network-scripts]# cat ifcfg-ens32:0
BOOTPROTO=static
DEVICE=ens32:0
ONBOOT=yes
IPADDR=10.10.10.100
PREFIX=24
[root@a network-scripts]# systemctl restart network

3、修改内核配置文件
关闭广播功能
[root@a network-scripts]# echo 0 > /proc/sys/net/ipv4/conf/all/send_redirects
[root@a network-scripts]# echo 0 > /proc/sys/net/ipv4/conf/default/send_redirects 
[root@a network-scripts]# echo 0 > /proc/sys/net/ipv4/conf/ens32/send_redirects

4、安装ipvsadm
lvs的管理工具
[root@a network-scripts]# yum install -y ipvsadm

5、关闭防火墙和selinux
[root@a network-scripts]# systemctl stop firewalld
[root@a network-scripts]# systemctl disable firewalld
[root@a network-scripts]# setenforce 0

RS配置(all):

1、安装apache并写入内容
[root@a ~]# yum install -y httpd
[root@a ~]# echo "this is server 1" >> /var/www/html/index.html
[root@a ~]# systemctl restart httpd
[root@a ~]# systemctl enable httpd
[root@a ~]# curl localhost
this is server 1

2、开启网卡子接口
配置VIP
[root@a ~]# cd /etc/sysconfig/network-scripts/
[root@a network-scripts]# cp -a ifcfg-lo ifcfg-lo:0
[root@a network-scripts]# cat ifcfg-lo:0
DEVICE=lo:0
IPADDR=10.10.10.100
NETMASK=255.255.255.255
NETWORK=127.0.0.0
# If you're having problems with gated making 127.0.0.0/8 a martian,
# you can change this to something else (255.255.255.255, for example)
BROADCAST=127.255.255.255
ONBOOT=yes
NAME=loopback
[root@a network-scripts]# systemctl restart network
3、ARP行为控制
[root@a network-scripts]# echo "1" > /proc/sys/net/ipv4/conf/lo/arp_ignore
[root@a network-scripts]# echo "2" > /proc/sys/net/ipv4/conf/lo/arp_announce
[root@a network-scripts]# echo "1" > /proc/sys/net/ipv4/conf/all/arp_ignore
[root@a network-scripts]# echo "2" > /proc/sys/net/ipv4/conf/all/arp_announce
刷新
[root@a network-scripts]# sysctl -p
4、添加路由
[root@a network-scripts]# route add -host 10.10.10.100 dev lo:0
[root@a network-scripts]# echo "route add -host 10.10.10.100 dev lo:0" >> /etc/rc.local

5、关闭防火墙和selinux
[root@a network-scripts]# systemctl stop firewalld
[root@a network-scripts]# systemctl disable firewalld
[root@a network-scripts]# setenforce 0

6、设置LBC
参数说明：
-A:添加集群
-a：集群子节点
-t：tcp协议
-s：算法
-r：真实服务器
-g：DR模式
[root@a ~]# ipvsadm -A -t 10.10.10.100:80 -s rr
[root@a ~]# ipvsadm -a -t 10.10.10.100:80 -r 10.10.10.12:80 -g 
[root@a ~]# ipvsadm -a -t 10.10.10.100:80 -r 10.10.10.13:80 -g
[root@a ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  10.10.10.100:80 rr
  -> 10.10.10.12:80               Route   1      0          0         
  -> 10.10.10.13:80               Route   1      0          0         

[root@a ~]# ipvsadm --save > /etc/sysconfig/ipvsadm
[root@a ~]# systemctl start ipvsadm.service
[root@a ~]# systemctl enable ipvsadm.service

7、测试
lvs会把请求按rr算法分给rs
[root@a network-scripts]# ipvsadm -Ln --stats
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port               Conns   InPkts  OutPkts  InBytes OutBytes
  -> RemoteAddress:Port
TCP  10.10.10.100:80                    24      164        0    24880        0
  -> 10.10.10.12:80                     12       94        0    16209        0
  -> 10.10.10.13:80                     12       70        0     8671        0

(2)部署keepalived

				在lvs上配置和一台新的虚拟机上配置
[root@a ~]# cd /etc/sysconfig/network-scripts/
[root@a ~]# scp ./ifcfg-ens32:0 10.10.10.14:/etc/sysconfig/network-scripts/ifcfg-ens32:0						
[root@a ~]# yum install -y keepalived

#配置keepalived配置文件
[root@a ~]# cat /etc/keepalived/keepalived.conf|head -50
! Configuration File for keepalived

global_defs {
   router_id R1
}

vrrp_instance VI_1 {
    state MASTER
    interface ens32
    virtual_router_id 66
    priority 50
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
	10.10.10.100    
}
}

virtual_server 10.10.10.100 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 10.10.10.12 80 {
        weight 1
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 80        
}
}
real_server 10.10.10.13 80 {
weight 1
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 80
}

}
}
从节点配置基本一致，
修改以下配置
router_id R2
state SLAVE
priority 20



在从节点安装ipvsadm
[root@a network-scripts]# yum install -y ipvsadm
[root@a network-scripts]# ipvsadm -l
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn

第一次查看没有集群信息，重启keepalived服务后会发现集群信息已经同步在两个节点


[root@a network-scripts]# systemctl restart keepalived
[root@a network-scripts]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  10.10.10.100:80 rr persistent 50
  -> 10.10.10.12:80             Route   1      0          0         
  -> 10.10.10.13:80             Route   1      0          0     

（3）进行测试

断开lvs调度器的网卡再次测试


断开web1服务器