Keepalived+LVS高可用负载服务器

 

3.1 问题

使用Keepalived为LVS调度器提供高可用功能，防止调度器单点故障，为用户提供Web服务：

• 路由器对外公网IP地址为202.114.106.20
• 路由器内网IP地址为192.168.0.254
• 路由是需要设置SNAT及DNAT功能
• LVS1调度器真实IP地址为192.168.0.10
• LVS2调度器真实IP地址为192.168.0.20
• 服务器VIP地址设置为192.168.0.253
• 真实Web服务器地址分别为192.168.0.1、192.168.0.2
• 使用加权轮询调度算法，真实服务器权重与其IP地址末尾数一致

3.2 方案

使用5台虚拟机，1台作为Linux路由器、2台作为LVS调度器、2台作为Real Server、物理机作为客户端，拓扑结构如图-2所示。

图-3

3.3 步骤

实现此案例需要按照如下步骤进行。

步骤一：配置网络环境

1）设置Web服务器网络参数

[root@web1 ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=static
IPADDR=192.168.0.1
NETMASK=255.255.255.0
GATEWAY=192.168.0.254
DNS1=202.106.0.20

[root@web1 ~]# vim /etc/sysconfig/network-scripts/ifcfg-lo:0  #VIP设置
DEVICE=lo:0
ONBOOT=yes
BOOTPROTO=static
IPADDR=192.168.0.253
NETMASK=255.255.255.255

[root@web1 ~]# vim /etc/sysctl.conf
.. ..
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.lo.arp_ignore = 1
net.ipv4.conf.lo.arp_announce = 2
net.ipv4.conf.all.arp_announce = 2
[root@web1 ~]# sysctl -p
[root@web1 ~]# service NetworkManager stop
[root@web1 ~]# chkconfig NetworkManager off
[root@web1 ~]# service network restart
[root@web1 ~]# iptables -F;service iptables save
##################
[root@web2 ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=static
IPADDR=192.168.0.2
NETMASK=255.255.255.0
GATEWAY=192.168.0.254
DNS1=202.106.0.20

[root@web2 ~]# vim /etc/sysconfig/network-scripts/ifcfg-lo:0  #VIP设置
DEVICE=lo:0 
ONBOOT=yes
BOOTPROTO=static
IPADDR=192.168.0.253
NETMASK=255.255.255.255

[root@web2 ~]# vim /etc/sysctl.conf
.. ..
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.lo.arp_ignore = 1
net.ipv4.conf.lo.arp_announce = 2
net.ipv4.conf.all.arp_announce = 2
[root@web2 ~]# sysctl -p
[root@web2 ~]# service NetworkManager stop
[root@web2 ~]# chkconfig NetworkManager off
[root@web2 ~]# service network restart
[root@web2 ~]# iptables -F;service iptables save

2）自定义Web页面

[root@web1 ~]# echo “192.168.0.1” > /var/www/html/index.html
[root@web2 ~]# echo “192.168.0.2” > /var/www/html/index.html

3）启动Web服务器软件

[root@web1 ~]# service httpd start;chkconfig httpd on
[root@web2 ~]# service httpd start;chkconfig httpd on

4)设置LVS调度器网络参数

[root@lvs1 ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=static
IPADDR=192.168.0.10
NETMASK=255.255.255.0
GATEWAY=192.168.0.254
DNS1=202.106.0.20
[root@lvs1 ~]# service NetworkManager stop
[root@lvs1 ~]# chkconfig NetworkManager off
[root@lvs1 ~]# service network restart
[root@lvs1 ~]# iptables -F;service iptables save
[root@lvs2 ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=static
IPADDR=192.168.0.20
NETMASK=255.255.255.0
GATEWAY=192.168.0.254
DNS1=202.106.0.20
[root@lvs2 ~]# service NetworkManager stop
[root@lvs2 ~]# chkconfig NetworkManager off
[root@lvs2 ~]# service network restart
[root@lvs2 ~]# iptables -F;service iptables save

5）设置Linux路由器网络参数

[root@router ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=static
IPADDR=202.114.106.20
DNS1=202.106.0.20
[root@router ~]# vim /etc/sysconfig/network-scripts/ifcfg-eth1
DEVICE=eth0
ONBOOT=yes
BOOTPROTO=static
IPADDR=192.168.0.254
NETMASK=255.255.255.0
DNS1=202.106.0.20
[root@router ~]# service NetworkManager stop
[root@router ~]# chkconfig NetworkManager off
[root@router ~]# service network restart
[root@router ~]# iptables -F;service iptables save

6）设置Linux路由器的SNAT、DNAT功能

[root@router ~]# sed -i '/ip_forward/s/0/1/' sysctl.conf //开启路由转发
[root@router ~]# sysctl -p
[root@router ~]# iptables -t nat -A POSTROUTING -s 192.168.0.0/24 -p tcp –j SNAT --to-source 202.114.106.20
[root@router ~]# iptables -t nat -A PREROUTING -d 202.114.106.20 -p tcp --dport 80 –j DNAT --to-destination 192.168.0.253:80
[root@router ~]# service iptables save

步骤二：调度器安装Keepalived与ipvsadm软件

注意：两台LVS调度器执行相同的操作。

安装软件

[root@lvs1 ~]# yum install -y gcc kernel-devel openssl-devel popt-devel
[root@lvs1 ~]# tar -xzf keepalived-1.2.7.tar.gz
[root@lvs1 ~]# cd keepalived-1.2.7
[root@lvs1 keepalived-1.2.7]# ./configure --sysconf=/etc
[root@lvs1 keepalived-1.2.7]# make && make install
[root@lvs1 keepalived-1.2.7]# ln -s /usr/local/sbin/keepalived /sbin/
[root@lvs1 keepalived-1.2.7]# chkconfig keepalived on
[root@lvs1 Pacages]# rpm –ihv ipvsadm-1.25-10.el6.x86_64.rpm
[root@lvs2 ~]# yum install -y gcc kernel-devel openssl-devel popt-devel
[root@lvs2 ~]# tar -xzf keepalived-1.2.7.tar.gz
[root@lvs2 ~]# cd keepalived-1.2.7
[root@lvs2 keepalived-1.2.7]# ./configure --sysconf=/etc
[root@lvs2 keepalived-1.2.7]# make && make install
[root@lvs2 keepalived-1.2.7]# ln -s /usr/local/sbin/keepalived /sbin/
[root@lvs2 keepalived-1.2.7]# chkconfig keepalived on
[root@lvs2 Pacages]# rpm –ihv ipvsadm-1.25-10.el6.x86_64.rpm

步骤三：部署Keepalived实现LVS-DR模式调度器的高可用

1）LVS1调度器设置Keepalived，并启动服务

[root@lvs1 ~]# vim /etc/keepalived/keepalived.conf
global_defs {
  notification_email {
    admin@tarena.com.cn                //设置报警收件人邮箱
  }
  notification_email_from ka@localhost    //设置发件人
  smtp_server 127.0.0.1                //定义邮件服务器
  smtp_connect_timeout 30
  router_id  lvs1                        //设置路由ID号
}
vrrp_instance VI_1 {
  state MASTER                             //主服务器为MASTER
  interface eth0                        //定义网络接口
  virtual_router_id 50                    //主辅VRID号必须一致
  priority 100                         //服务器优先级
  advert_int 1
  authentication {
    auth_type pass
    auth_pass forlvs                       //主辅服务器密码必须一致
  }
  virtual_ipaddress {  192.168.0.253  }
}
virtual_server 192.168.0.253 80 {       //设置VIP为192.168.0.253
  delay_loop 6
  lb_algo wrr                          //设置LVS调度算法为RR
  lb_kind DR                               //设置LVS的模式为DR
  persistence_timeout 1
  protocol TCP
  real_server 192.168.0.1 80 {
    weight 1                          //设置权重为1
    TCP_CHECK {
    connect_timeout 3
    nb_get_retry 3
    delay_before_retry 3
    }
  }
 real_server 192.168.0.2 80 {
    weight 2                          //设置权重为2
    TCP_CHECK {
    connect_timeout 3
    nb_get_retry 3
    delay_before_retry 3
    }
  }
[root@lvs1 ~]# service keepalived start
[root@lvs1 ~]# ipvsadm -Ln

2）LVS2调度器设置Keepalived

[root@lvs1 ~]# vim /etc/keepalived/keepalived.conf
global_defs {
  notification_email {
    admin@tarena.com.cn                //设置报警收件人邮箱
  }
  notification_email_from ka@localhost    //设置发件人
  smtp_server 127.0.0.1                //定义邮件服务器
  smtp_connect_timeout 30
  router_id  lvs2                        //设置路由ID号
}
vrrp_instance VI_1 {
  state SLAVE                             //从服务器为SLAVE
  interface eth0                        //定义网络接口
  virtual_router_id 50                    //主辅VRID号必须一致
  priority 50                         //服务器优先级
  advert_int 1
  authentication {
    auth_type pass
    auth_pass forlvs                       //主辅服务器密码必须一致
  }
  virtual_ipaddress {  192.168.0.253  }
}
virtual_server 192.168.0.253 80 {       //设置VIP为192.168.0.253
  delay_loop 6
  lb_algo wrr                          //设置LVS调度算法为RR
  lb_kind DR                               //设置LVS的模式为DR
  persistence_timeout 1
  protocol TCP
  real_server 192.168.0.1 80 {
    weight 1                          //设置权重为1
    TCP_CHECK {
    connect_timeout 3
    nb_get_retry 3
    delay_before_retry 3
    }
  }
 real_server 192.168.0.2 80 {
    weight 2                          //设置权重为2
    TCP_CHECK {
    connect_timeout 3
    nb_get_retry 3
    delay_before_retry 3
    }
  }
[root@lvs2 ~]# service keepalived start
[root@lvs2 ~]# ipvsadm -Ln

步骤四：客户端测试

客户端使用curl命令反复连接http://202.114.106.20，查看访问的页面是否会轮询到不同的后端真实服务器。