了解基于LVS负载均衡群集来实现Keepalived的部署

一、Keepalived案例分析

·企业应用中，单台服务器承担应用存在单点故障的危险

·单点故障一旦发生，企业服务将发生中断，造成极大的危害

二、Keepalived工具介绍

1、专为LVS和HA设计的一款健康检查工具

·支持故障自动切换（Failover）

·支持节点健康状态检查（Health Checking）

·官方网站：http://www.Keepalived.org/

三、Keepalived实现原理剖析

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

2、VRRP（虚拟路由冗余协议）是针对路由器的一种备份解决方案

 ·由多台路由器组成一个热备组，通过共用的虚拟IP地址对外提供服务

·每个热备组内同时只有一台主路由器提供服务，其他路由器处于冗余状态

·若当前在线的路由器失效，则其他路由器会根据设置的优先级自动接替虚拟IP地址，继续提供服务

四、Keepalived案例讲解

1、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

2、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

3、环境(基于LVS-DR进行搭建)

4、配置主调度器（192.168.100.10）

加载ip_vs模块

[root@lvs-zhu ~]# modprobe ip_vs
[root@lvs-zhu ~]# cat /proc/net/ip_vs
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port Forward Weight ActiveConn InActConn

安装管理软件ipvsadm
[root@lvs-zhu ~]# rpm -ivh /mnt/Packages/ipvsadm-1.27-7.el7.x86_64.rpm

安装编译工具
[root@lvs-zhu ~]# yum -y install gcc gcc-c++ make popt-devel openssl-devel kernel-devel

解压缩，编译安装
[root@lvs-zhu ~]# tar zxf keepalived-2.0.13.tar.gz
[root@lvs-zhu ~]# cd keepalived-2.0.13/
[root@lvs-zhu keepalived-2.0.13]# ./configure --prefix=/
[root@lvs-zhu keepalived-2.0.13]# make && make install

加入系统管理服务，设置开机自启
[root@lvs-zhu keepalived-2.0.13]# cp keepalived/etc/init.d/keepalived /etc/init.d/
[root@lvs-zhu keepalived-2.0.13]# systemctl enable keepalived.service

编辑配置文件
[root@lvs-zhu keepalived-2.0.13]# vi /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
      router_id LVS_01           　　　#本服务器的名称
}
vrrp_instance VI_1 {             　　　#定义VRRP热备实例
      state MASTER               　　　#热备状态，MASTER表示主服务器，BACKUP表示从服务器
      interface ens33            　　　#承载VIP地址的物理接口
      virtual_router_id 51       　　　#虚拟路由器的ID号，每个热备组保持一致
      priority 110               　　　#优先级，数值越大优先级越高
      advert_int 1               　　　#通告间隔秒数（心跳频率）
      authentication {           　　　#热备认证信息，每个热备组保持一致
            auth_type PASS       　　　#认证类型
            auth_pass 6666       　　　#密码字符串
      }
      virtual_ipaddress {        　　　#指定飘逸地址（VIP），可以有多个
            192.168.100.100
      }
}
virtual_server 192.168.100.100 80 {　　#虚拟服务器地址（VIP）、端口
            delay_loop 6              #健康检查的间隔时间（秒）
            lb_algo rr                #轮询（rr）调度算法
            lb_kind DR                #直接路由（DR）群集工作模式
            persistence_timeout 6     #连接保持时间（秒）
            protocol TCP              #应用服务器采用的是TCP协议
real_server 192.168.100.20 80 {       #第一个web服务器节点的地址、端口
            weight 1                  #节点的权重
            TCP_CHECK {               #健康检查方式
            connect_port 80           #检查的目标端口
            connect_timeout 3         #连接超时（秒）
            nb_get_retry 3            #重试次数
            delay_before_retry 3      #重试间隔
            }
}
real_server 192.168.100.30 80 {
            weight 1
            TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            }
    }
}

开启服务
[root@lvs-zhu keepalived-2.0.13]# systemctl start keepalived.service
[root@lvs-zhu keepalived-2.0.13]# tail -f /var/log/messages
[root@lvs-zhu keepalived-2.0.13]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.100.100:80 rr persistent 6
  -> 192.168.100.20:80            Route   1      0          0
  -> 192.168.100.30:80            Route   1      0          0
[root@lvs-zhu keepalived-2.0.13]# ip addr show dev ens33
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:9a:cd:27 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.10/24 brd 192.168.100.255 scope global ens33
       valid_lft forever preferred_lft forever
    inet 192.168.100.100/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::26b5:ebd3:a0d2:db12/64 scope link
       valid_lft forever preferred_lft forever

5、配置从调度器（192.168.100.40）

加载ip_vs模块
[root@lvs-bei ~]# modprobe ip_vs
[root@lvs-bei ~]# cat /proc/net/ip_vs
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port Forward Weight ActiveConn InActConn

安装管理软件ipvsadm
[root@lvs-bei ~]# rpm -ivh /mnt/Packages/ipvsadm-1.27-7.el7.x86_64.rpm

安装编译工具
[root@lvs-bei ~]# yum -y install gcc gcc-c++ make popt-devel openssl-devel kernel-devel

解压缩，编译安装
[root@lvs-bei ~]# tar zxf keepalived-2.0.13.tar.gz
[root@lvs-bei ~]# cd keepalived-2.0.13/
[root@lvs-bei keepalived-2.0.13]# ./configure --prefix=/
[root@lvs-bei keepalived-2.0.13]# make && make install

加入系统管理服务，设置开机自启
[root@lvs-bei keepalived-2.0.13]# cp keepalived/etc/init.d/keepalived /etc/init.d/
[root@lvs-bei keepalived-2.0.13]# systemctl enable keepalived.service

编辑配置文件
[root@lvs-bei keepalived-2.0.13]# vi /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
      router_id LVS_02           　　　#本服务器的名称
}
vrrp_instance VI_1 {             　　　#定义VRRP热备实例
      state BACKUP               　　　#热备状态，MASTER表示主服务器，BACKUP表示从服务器
      interface ens33            　　　#承载VIP地址的物理接口
      virtual_router_id 51       　　　#虚拟路由器的ID号，每个热备组保持一致
      priority 105               　　　#优先级，数值越大优先级越高
      advert_int 1               　　　#通告间隔秒数（心跳频率）
      authentication {           　　　#热备认证信息，每个热备组保持一致
            auth_type PASS       　　　#认证类型
            auth_pass 6666       　　　#密码字符串
      }
      virtual_ipaddress {        　　　#指定飘逸地址（VIP），可以有多个
            192.168.100.100
      }
}
virtual_server 192.168.100.100 80 {　　＃虚拟服务器地址（VIP）、端口
            delay_loop 6              #健康检查的间隔时间（秒）
            lb_algo rr                #轮询（rr）调度算法
            lb_kind DR                #直接路由（DR）群集工作模式
            persistence_timeout 6     #连接保持时间（秒）
            protocol TCP              #应用服务器采用的是TCP协议
real_server 192.168.100.20 80 {       #第一个web服务器节点的地址、端口
            weight 1                  #节点的权重
            TCP_CHECK {               #健康检查方式
            connect_port 80           #检查的目标端口
            connect_timeout 3         #连接超时（秒）
            nb_get_retry 3            #重试次数
            delay_before_retry 3      #重试间隔
            }
}
real_server 192.168.100.30 80 {
            weight 1
            TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
            }
    }
}

开启服务
[root@lvs-bei keepalived-2.0.13]# systemctl start keepalived.service
[root@lvs-bei keepalived-2.0.13]# tail -f /var/log/messages
[root@lvs-bei keepalived-2.0.13]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.100.100:80 rr
  -> 192.168.100.20:80            Route   1      0          0
  -> 192.168.100.30:80            Route   1      0          0
[root@lvs-bei keepalived-2.0.13]# ip addr show dev ens33
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:dc:10:18 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.40/24 brd 192.168.100.255 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::c1f0:d588:3477:d684/64 scope link
       valid_lft forever preferred_lft forever

####由于设置了连接保持时间为60秒，一分钟后重新再访问该地址自动轮询交给另一台Web服务器

6、配置NFS服务器（192.168.100.50）

安装NFS服务
[root@nfs-server ~]# yum -y install rpcbind nfs-utils

创建测试目录并新建网页
[root@nfs-server ~]# mkdir -p /opt/web1
[root@nfs-server ~]# mkdir -p /opt/web2
[root@nfs-server ~]# echo '<h1>this is web 1!</h1>' > /opt/web1/index.html
[root@nfs-server ~]# echo '<h1>this is web 2!</h1>' > /opt/web2/index.html

设置访问权限
[root@nfs-server ~]# vi /etc/exports
/opt/web1  192.168.100.20(ro)
/opt/web2  192.168.100.30(ro)

开启服务并开机自启
[root@nfs-server ~]# systemctl start nfs
[root@nfs-server ~]# systemctl start rpcbind
[root@nfs-server ~]# systemctl enable nfs
[root@nfs-server ~]# systemctl enable rpcbind

查看访问权限
[root@nfs-server ~]# showmount -e
Export list for nfs-server:
/opt/web2 192.168.100.30
/opt/web1 192.168.100.20

7、配置Web1服务器（192.168.100.20）

安装httpd服务
[root@web1 ~]# yum -y install httpd

挂载NFS服务
[root@web1 ~]# mount 192.168.100.50:/opt/web1 /var/www/html

查看权限
[root@web1 ~]# showmount -e 192.168.100.50
Export list for 192.168.100.50:
/opt/web2 192.168.100.30
/opt/web1 192.168.100.20

开启httpd服务
[root@web1 ~]# systemctl start httpd

本机访问
[root@web1 ~]# curl http://localhost
<h1>this is web1!</h1>

配置DR模式
[root@web1 ~]# vi web1.sh
#!/bin/bash
# web1
ifconfig lo:0 192.168.100.100 broadcast 192.168.100.100 netmask 255.255.255.255 up
route add -host 192.168.100.100 dev lo:0
echo "1" > /proc/sys/net/ipv4/conf/lo/arp_ignore
echo "1" > /proc/sys/net/ipv4/conf/all/arp_ignore
echo "2" > /proc/sys/net/ipv4/conf/lo/arp_announce
echo "2" > /proc/sys/net/ipv4/conf/all/arp_announce
sysctl -p &> /dev/null

执行脚本
[root@web1 ~]# sh web1.sh

查看端口信息
[root@web1 ~]# ifconfig
......
lo:0: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 192.168.100.100  netmask 255.255.255.255
        loop  txqueuelen 1  (Local Loopback)
......

8、配置web2服务器（192.168.100.30）

安装httpd服务
[root@web2 ~]# yum -y install httpd

挂载NFS服务
[root@web2 ~]# mount 192.168.100.50:/opt/web2 /var/www/html

查看权限
[root@web2 ~]# showmount -e 192.168.100.50
Export list for 192.168.100.50:
/opt/web2 192.168.100.30
/opt/web1 192.168.100.20

开启httpd服务
[root@web2 ~]# systemctl start httpd

本机访问
[root@web2 ~]# curl http://localhost
<h1>this is web2!</h1>

配置DR模式
[root@web2 ~]# vi web2.sh
#!/bin/bash
# web2
ifconfig lo:0 192.168.100.100 broadcast 192.168.100.100 netmask 255.255.255.255 up
route add -host 192.168.100.100 dev lo:0
echo "1" > /proc/sys/net/ipv4/conf/lo/arp_ignore
echo "1" > /proc/sys/net/ipv4/conf/all/arp_ignore
echo "2" > /proc/sys/net/ipv4/conf/lo/arp_announce
echo "2" > /proc/sys/net/ipv4/conf/all/arp_announce
sysctl -p &> /dev/null

执行脚本
[root@web2 ~]# sh web2.sh

查看端口信息
[root@web2 ~]# ifconfig
......
lo:0: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 192.168.100.100  netmask 255.255.255.255
        loop  txqueuelen 1  (Local Loopback)
......

9、测试web1和web2的IP访问

10、测试虚拟IP地址级查看状态

 

[root@lvs-zhu keepalived-2.0.13]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.100.100:80 rr
  -> 192.168.100.20:80            Route   1      1          1
  -> 192.168.100.30:80            Route   1      1          0

 11、模拟主调度器故障，验证结果

关闭主调度器keepalived
[root@lvs-zhu keepalived-2.0.13]# systemctl stop keepalived.service

查看从调度器状态
[root@lvs-bei keepalived-2.0.13]# tail -f /var/log/messages
[root@lvs-bei keepalived-2.0.13]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.100.100:80 rr
  -> 192.168.100.20:80            Route   1      0          0
  -> 192.168.100.30:80            Route   1      0          0
[root@lvs-bei keepalived-2.0.13]# ip addr show dev ens33
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:dc:10:18 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.40/24 brd 192.168.100.255 scope global ens33
       valid_lft forever preferred_lft forever
    inet 192.168.100.100/32 scope global ens33
       valid_lft forever preferred_lft forever                    #虚拟地址漂移到备调度器上
    inet6 fe80::c1f0:d588:3477:d684/64 scope link
       valid_lft forever preferred_lft forever

 查看备调度器连接状态

[root@lvs-bei keepalived-2.0.13]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.100.100:80 rr
  -> 192.168.100.20:80            Route   1      0          1
  -> 192.168.100.30:80            Route   1      2          0

12、开启主调度器并查看状态

[root@lvs-zhu keepalived-2.0.13]# systemctl start keepalived.service
[root@lvs-zhu keepalived-2.0.13]# tail -f /var/log/messages
[root@lvs-zhu keepalived-2.0.13]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.100.100:80 rr
  -> 192.168.100.20:80            Route   1      0          0
  -> 192.168.100.30:80            Route   1      0          0
[root@lvs-zhu keepalived-2.0.13]# ip addr show dev ens33
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:9a:cd:27 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.10/24 brd 192.168.100.255 scope global ens33
       valid_lft forever preferred_lft forever
    inet 192.168.100.100/32 scope global ens33
       valid_lft forever preferred_lft forever                         #虚拟地址又到主调度器上
    inet6 fe80::26b5:ebd3:a0d2:db12/64 scope link
       valid_lft forever preferred_lft forever

13、模拟web服务器故障，查看状态

①关闭web1的httpd服务

1 [root@web1 ~]# systemctl stop httpd

②测试网页，只能查看web2服务器的网页

 ③查看调度器节点状态

[root@lvs-zhu keepalived-2.0.13]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.100.100:80 rr
  -> 192.168.100.30:80            Route   1      1          2

④开启Web1服务又可以轮询了

[root@lvs-zhu keepalived-2.0.13]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.100.100:80 rr
  -> 192.168.100.20:80            Route   1      2          0
  -> 192.168.100.30:80            Route   1      3          1