LVS+Keepalived集群

Keepalived双机热备

Keepalived实现原理刨析

Keepalived采用VRRP热备份协议实现Linux服务器的多机热备功能

Keepalived案例分析

Keepalived可以实现多机热备，每个热备组可有多台服务器

双机热备的故障切换是由虚拟IP地址的漂移来实现，适用于各种应用服务器'

实现基于web服务的双机热备

• 漂移地址：192.168.10.72
• 主、备服务器：192.168.10.73、192.168.10.74
• 提供的应用服务：Web

LVS+Keepalived高可用性

配置主调度器

安装keepalived

[root@localhost ~]# systemctl stop NetworkManager
[root@localhost ~]# setenforce 0
[root@localhost ~]# systemctl stop firewalld

[root@localhost ~]# yum -y install keepalived ipvsadm
[root@localhost ~]# systemctl enable keepalived

主服务器keepalived的配置

[root@localhost keepalived]# cp keepalived.conf keepalived.conf.bak

[root@localhost keepalived]# vi keepalived.conf
global_defs {
   notification_email {
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   #vrrp_strict            //抢占模式
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_01        //路由id
}

vrrp_instance VI_1 {
    state MASTER            //热备状态，MASTER表示服务器
    interface ens33        //承载VIP地址的物理接口
    virtual_router_id 51    //虚拟路由的ID
    priority 100           //优先级
    advert_int 1
    authentication {
        auth_type PASS        //连接方式
        auth_pass 1111        //密码
    }
    virtual_ipaddress {        //指定漂移地址
        192.168.10.172
    }
}

virtual_server 192.168.10.172 80 {
    delay_loop 6
    lb_algo rr           //调度算法
    lb_kind DR           //
    nat_mask 255.255.255.0
!    persistence_timeout 50
    protocol TCP

    real_server 192.168.10.103 80 {
        weight 1
        TCP_CHECK {
            connect_port 80        //连接端口
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
    real_server 192.168.10.104 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

}

主内核参数的配置

[root@localhost ~]# vi /etc/sysctl.conf
............
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0
net.ipv4.conf.ens33.send_redirects = 0
[root@localhost ~]# sysctl -p

开启主服务器的keepalived服务

[root@localhost ~]# systemctl start keepalived
[root@localhost keepalived]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:be:c5:4c brd ff:ff:ff:ff:ff:ff
    inet 192.168.10.101/24 brd 192.168.10.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.10.172/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::fc95:68f1:8f59:7f55/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

配置从调度器

从调度器keepalived安装

[root@localhost ~]# systemctl stop NetworkManager
[root@localhost ~]# setenforce 0
[root@localhost ~]# systemctl stop firewalld

[root@localhost ~]# yum -y install keepalived ipvsadm
[root@localhost ~]# systemctl enable keepalived

从调度器keepalived的配置

[root@localhost ~]# cd /etc/keepalived/
[root@localhost keepalived]# cp keepalived.conf keepalived.conf.bak

[root@localhost keepalived]# vi keepalived.conf
global_defs {
   notification_email {
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   #vrrp_strict
   smtp_server 192.168.200.1
   smtp_connect_timeout 30
   router_id LVS_02
}

vrrp_instance VI_1 {
    state BACKUP                //热备状态，BACKUP表示从服务器
    interface ens33
    virtual_router_id 51
    priority 99                //从服务器的优先级要低于主服务器
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.10.172
    }
}

virtual_server 192.168.10.172 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    nat_mask 255.255.255.0
!    persistence_timeout 50
    protocol TCP

    real_server 192.168.10.101 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
    real_server 192.168.10.102 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

}

从服务器内核参数的配置

[root@localhost ~]# vi /etc/sysctl.conf
在末尾添加：
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0
net.ipv4.conf.ens33.send_redirects = 0
[root@localhost ~]# sysctl -p

开启从服务器的keepalived服务

[root@localhost keepalived]# systemctl start keepalived

服务器池配置

两个web服务器节点配置

（1）网络配置

[root@localhost ~]# systemctl stop firewalld
[root@localhost ~]# cd /etc/sysconfig/network-scripts/
[root@localhost network-scripts]# cp ifcfg-lo ifcfg-lo:0
[root@localhost network-scripts]# vi ifcfg-lo:0
DEVICE=lo:0
IPADDR=192.168.10.172
NETMASK=255.255.255.255
ONBOOT=yes

[root@localhost network-scripts]# systemctl restrt network
[root@localhost network-scripts]# vi /etc/rc.local
route add -host 192.168.10.172 dev lo:0
[root@localhost ~]# route add -host 192.168.10.172 dev lo:0

（2）httpd服务安装

[root@localhost ~]# yum -y install httpd
[root@localhost ~]# vim /var/www/html/index.html
test web1 //两个web节点服务器要看出差别即可

test web2

(3)内核参数设置

（3）内核参数的设置
[root@localhost ~]# vi /etc/sysctl.conf
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2
net.ipv4.conf.default.arp_ignore = 1
net.ipv4.conf.default.arp_announce = 2
net.ipv4.conf.lo.arp_ignore = 1
net.ipv4.conf.lo.arp_announce = 2

（4）启动httpd服务

[root@localhost ~]# systemctl start httpd

测试LVS+Keepalived高可用性

在客户端使用脚本测试

[root@localhost ~]# for i in $(seq 10); do curl 192.168.10.172  ;done
test web01
test web02
test web01
test web02
test web01