keepalived高可用实例

1、keepalived单实例

1)实验环境为VMware虚拟机,两台centos7.2,主机1IP地址为10.1.252.55,主机2IP地址为10.1.252.34,虚拟路由IP为10.1.252.246,
2)确保iptables和selinux不影响实验

(1)确保两台主机的时间同步

[root@localhost ~]# vim /etc/chrony.conf
    server 10.1.0.1 iburst  (这个是我们局域网内的NTP服务器,读者可自行安装NTP服务器;若虚拟机可以上网(NAT模式),可以用公共的NTP服务器同步时间)
[root@localhost ~]# chronyc sources
506 Cannot talk to daemon  (chrony服务没有启动)
[root@localhost ~]# systemctl start chronyd
[root@localhost ~]# chronyc sources
210 Number of sources = 1
MS Name/IP address         Stratum Poll Reach LastRx Last sample
===============================================================================
^? 10.1.0.1                      0   7     0   10y     +0ns[   +0ns] +/-    0ns
[root@localhost ~]# ntpdate 10.1.0.1 (手动强行同步时间)

(2)基于ssh服务通信(非必要步骤,可跳过此步)

[root@localhost ~]# ssh-keygen -t rsa -P ''
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa):         
Your identification has been saved in /root/.ssh/id_rsa.
Your public key has been saved in /root/.ssh/id_rsa.pub.
The key fingerprint is:
bc:8f:ee:48:47:30:fc:9c:ac:49:d6:eb:48:16:80:ef root@localhost.localdomain
The key's randomart image is:
+--[ RSA 2048]----+
|                 |
|   . .           |
|  . . +          |
|   . . O .       |
|    . + S        |
|   . o = o       |
|    E * +        |
|     + = o       |
|      oo= .      |
+-----------------+

[root@node1 ~]# ssh-copy-id -i .ssh/id_rsa.pub root@10.1.252.34  (复制到主机2)
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
root@10.1.252.34's password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh 'root@10.1.252.34'"
and check to make sure that only the key(s) you wanted were added.

[root@node1 ~]# ssh 10.1.252.34 'pwd' (在主机1上可以不用密码执行主机2上的命令)
/root

[root@node1 ~]# date;ssh 10.1.252.34 'date'
Mon Oct 31 19:58:47 CST 2016
Mon Oct 31 19:58:47 CST 2016

(3)主机1上安装并配置keepalived

1)注意网卡要支持多播功能

[root@localhost keepalived]# ip a
...
eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
....

MULTICAST:表示支持多播功能

2)安装keepalived

[root@node1 ~]# yum -y install keepalived

3)配置keepalived.conf

[root@node1 ~]# cd /etc/keepalived/
[root@node1 keepalived]# cp keepalived.conf{,.bak} (备份原文件)

[root@node1 keepalived]# vim keepalived.conf  (配置内容如下)

    ! Configuration File for keepalived

    global_defs {
       notification_email {  (接收信息的邮箱地址,真实环境中填写公开的邮箱,如@163.com)
         root@localhost
       }
       notification_email_from keepalived@localhost  (邮件发送者)
       smtp_server 127.0.0.1   (提供邮件服务的服务器)
       smtp_connect_timeout 30  (邮件连接超时时长)
       router_id node1  (路由节点ID标识)
       vrrp_mcast_group4 224.0.100.51  (组播地址)
    }

    vrrp_instance VI_51 {  (VI_51表示实例的ID,是唯一的)
        state MASTER    (指定那个为master,那个为backup,如果设置了nopreempt这个值不起作用,主备考priority决定)
        interface eno16777736   (指定当前实例绑定的网卡)
        virtual_router_id 210   (当前虚拟路由的唯一标识,范围是0-255)
        priority 100    (指定优先级,范围1-254)
        advert_int 1    (通告的时间间隔)
        authentication {    (验证方式)
            auth_type PASS
            auth_pass e8c59269
        }
        virtual_ipaddress {     (虚拟路由IP地址)
            10.1.252.246/16 dev eno16777736
        }
    }

(4)主机2上安装并配置keepalived

1)安装keepalived

[root@node1 ~]# yum -y install keepalived

2)在主机1中拷贝配置好的keepalived.conf文件到主机2

[root@node1 ~]# /etc/keepalived
[root@node1 keepalived]# scp keepalived.conf 10.1.252.34:/etc/keepalived/
keepalived.conf

3)修改拷贝过来的keepalived.conf文件

只需修改下两项,其他的不变
state MASTER 改为 state BACKUP
priority 100 改为 priority 98

(5)测试 ###

1)主机1中启动 keepalived服务,可看到如下情况

[root@node1 keepalived]# systemctl start keepalived.service
[root@node1 keepalived]# ip a l
    ......

    eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
        link/ether 00:0c:29:0e:27:cd brd ff:ff:ff:ff:ff:ff
        inet 10.1.252.55/16 brd 10.1.255.255 scope global dynamic eno16777736
           valid_lft 54812sec preferred_lft 54812sec
        inet 10.1.252.246/16 scope global secondary eno16777736
           valid_lft forever preferred_lft forever
        inet6 fe80::20c:29ff:fe0e:27cd/64 scope link 
           valid_lft forever preferred_lft forever

    ......

2)主机2中启动 keepalived服务,可看到如下情况

[root@localhost ~]# systemctl start keepalived
[root@localhost ~]# ip a l 
    ......

    eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
        link/ether 00:0c:29:e8:7c:bc brd ff:ff:ff:ff:ff:ff
        inet 10.1.252.34/16 brd 10.1.255.255 scope global dynamic eno16777736
           valid_lft 53649sec preferred_lft 53649sec
        inet6 fe80::20c:29ff:fee8:7cbc/64 scope link 
           valid_lft forever preferred_lft forever

    ......

3)主机1关闭keepalived服务,则主机2看到网卡情况如下,表示keepalived配置成功了

[root@node1 keepalived]# ip a l  (10.1.252.246切换到主机2中)
    ...... 

    eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
        link/ether 00:0c:29:0e:27:cd brd ff:ff:ff:ff:ff:ff
        inet 10.1.252.55/16 brd 10.1.255.255 scope global dynamic eno16777736
           valid_lft 54812sec preferred_lft 54812sec
        inet 10.1.252.246/16 scope global secondary eno16777736
           valid_lft forever preferred_lft forever
        inet6 fe80::20c:29ff:fe0e:27cd/64 scope link 
           valid_lft forever preferred_lft forever

2、keepalived双主模式实例

基于实例1,只需修改两个主机的主配文件,即在实例1主配文件后面再添加一个vrrp_instance

1)主机1上的操作

[root@localhost keepalived]# vim keepalived.conf
    ! Configuration File for keepalived

    global_defs {
       notification_email {
         root@localhost
       }
       notification_email_from keepalived@localhost
       smtp_server 127.0.0.1
       smtp_connect_timeout 30
       router_id node1
       vrrp_mcast_group4 224.0.100.51
    }

    vrrp_instance VI_51 {
        state MASTER
        interface eno16777736
        virtual_router_id 210
        priority 100
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass e8c59269
        }
        virtual_ipaddress {
            10.1.252.246/16 dev eno16777736
        }
    }

    vrrp_instance VI_52 {
        state BACKUP
        interface eno16777736
        virtual_router_id 212
        priority 98
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass e8c58268
        }
        virtual_ipaddress {
            10.1.252.248/16 dev eno16777736
        }
    }

2)主机2的配置

[root@localhost keepalived]# vim keepalived.conf
    ! Configuration File for keepalived

    global_defs {
       notification_email {
         root@localhost
       }
       notification_email_from keepalived@localhost
       smtp_server 127.0.0.1
       smtp_connect_timeout 30
       router_id node1
       vrrp_mcast_group4 224.0.100.51
    }

    vrrp_instance VI_51 {
        state BACKUP
        interface eno16777736
        virtual_router_id 210
        priority 98
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass e8c59269
        }
        virtual_ipaddress {
            10.1.252.246/16 dev eno16777736
        }
    }

    vrrp_instance VI_52 {
        state MASTER
        interface eno16777736
        virtual_router_id 212
        priority 100
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass e8c58268
        }
        virtual_ipaddress {
            10.1.252.248/16 dev eno16777736
        }
    }

3)测试

主机1启动keepalived服务,查看日志和IP地址变化

[root@localhost keepalived]# systemctl start keepalived.service
[root@localhost keepalived]# tail -20 /var/log/messages
    Oct 31 23:15:04 localhost Keepalived_healthcheckers[3986]: Netlink reflector reports IP fe80::20c:29ff:fe0e:27cd added
    Oct 31 23:15:04 localhost Keepalived_healthcheckers[3986]: Registering Kernel netlink reflector
    Oct 31 23:15:04 localhost Keepalived_healthcheckers[3986]: Registering Kernel netlink command channel
    Oct 31 23:15:04 localhost Keepalived_healthcheckers[3986]: Opening file '/etc/keepalived/keepalived.conf'.
    Oct 31 23:15:04 localhost Keepalived_healthcheckers[3986]: Configuration is using : 7931 Bytes
    Oct 31 23:15:04 localhost Keepalived_healthcheckers[3986]: Using LinkWatch kernel netlink reflector...
    Oct 31 23:15:05 localhost Keepalived_vrrp[3987]: VRRP_Instance(VI_51) Transition to MASTER STATE
    Oct 31 23:15:05 localhost Keepalived_vrrp[3987]: VRRP_Instance(VI_52) Transition to MASTER STATE
    Oct 31 23:15:06 localhost Keepalived_vrrp[3987]: VRRP_Instance(VI_51) Entering MASTER STATE
    Oct 31 23:15:06 localhost Keepalived_vrrp[3987]: VRRP_Instance(VI_51) setting protocol VIPs.
    Oct 31 23:15:06 localhost Keepalived_vrrp[3987]: VRRP_Instance(VI_51) Sending gratuitous ARPs on eno16777736 for 10.1.252.246
    Oct 31 23:15:06 localhost Keepalived_healthcheckers[3986]: Netlink reflector reports IP 10.1.252.246 added
    Oct 31 23:15:06 localhost avahi-daemon[819]: Registering new address record for 10.1.252.246 on eno16777736.IPv4.
    Oct 31 23:15:06 localhost Keepalived_vrrp[3987]: VRRP_Instance(VI_52) Entering MASTER STATE
    Oct 31 23:15:06 localhost Keepalived_vrrp[3987]: VRRP_Instance(VI_52) setting protocol VIPs.
    Oct 31 23:15:06 localhost Keepalived_vrrp[3987]: VRRP_Instance(VI_52) Sending gratuitous ARPs on eno16777736 for 10.1.252.248
    Oct 31 23:15:06 localhost Keepalived_healthcheckers[3986]: Netlink reflector reports IP 10.1.252.248 added
    Oct 31 23:15:06 localhost avahi-daemon[819]: Registering new address record for 10.1.252.248 on eno16777736.IPv4.
    Oct 31 23:15:11 localhost Keepalived_vrrp[3987]: VRRP_Instance(VI_51) Sending gratuitous ARPs on eno16777736 for 10.1.252.246
    Oct 31 23:15:11 localhost Keepalived_vrrp[3987]: VRRP_Instance(VI_52) Sending gratuitous ARPs on eno16777736 for 10.1.252.248

[root@localhost keepalived]# ip a l

......

eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:0e:27:cd brd ff:ff:ff:ff:ff:ff
    inet 10.1.252.55/16 brd 10.1.255.255 scope global eno16777736
       valid_lft forever preferred_lft forever
    inet 10.1.252.246/16 scope global secondary eno16777736
       valid_lft forever preferred_lft forever
    inet 10.1.252.248/16 scope global secondary eno16777736
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe0e:27cd/64 scope link 
       valid_lft forever preferred_lft forever

.......

启动主机2的keepalived服务,查看日志和ip地址变化

[root@localhost keepalived]# systemctl start keepalived.service 
[root@localhost keepalived]# tail -20 /var/log/messages
    Oct 31 23:22:36 localhost Keepalived_healthcheckers[11286]: Using LinkWatch kernel netlink reflector...
    Oct 31 23:22:36 localhost Keepalived_vrrp[11287]: Netlink reflector reports IP 10.1.252.34 added
    Oct 31 23:22:36 localhost Keepalived_vrrp[11287]: Netlink reflector reports IP 192.168.122.1 added
    Oct 31 23:22:36 localhost Keepalived_vrrp[11287]: Netlink reflector reports IP fe80::20c:29ff:fee8:7cbc added
    Oct 31 23:22:36 localhost Keepalived_vrrp[11287]: Registering Kernel netlink reflector
    Oct 31 23:22:36 localhost Keepalived_vrrp[11287]: Registering Kernel netlink command channel
    Oct 31 23:22:36 localhost Keepalived_vrrp[11287]: Registering gratuitous ARP shared channel
    Oct 31 23:22:36 localhost Keepalived_vrrp[11287]: Opening file '/etc/keepalived/keepalived.conf'.
    Oct 31 23:22:36 localhost Keepalived_vrrp[11287]: Configuration is using : 67091 Bytes
    Oct 31 23:22:36 localhost Keepalived_vrrp[11287]: Using LinkWatch kernel netlink reflector...
    Oct 31 23:22:36 localhost Keepalived_vrrp[11287]: VRRP_Instance(VI_51) Entering BACKUP STATE
    Oct 31 23:22:36 localhost Keepalived_vrrp[11287]: VRRP sockpool: [ifindex(2), proto(112), unicast(0), fd(10,11)]
    Oct 31 23:22:36 localhost systemd: Started LVS and VRRP High Availability Monitor.
    Oct 31 23:22:37 localhost Keepalived_vrrp[11287]: VRRP_Instance(VI_52) Transition to MASTER STATE
    Oct 31 23:22:37 localhost Keepalived_vrrp[11287]: VRRP_Instance(VI_52) Received lower prio advert, forcing new election
    Oct 31 23:22:38 localhost Keepalived_vrrp[11287]: VRRP_Instance(VI_52) Entering MASTER STATE
    Oct 31 23:22:38 localhost Keepalived_vrrp[11287]: VRRP_Instance(VI_52) setting protocol VIPs.
    Oct 31 23:22:38 localhost Keepalived_vrrp[11287]: VRRP_Instance(VI_52) Sending gratuitous ARPs on eno16777736 for 10.1.252.248
    Oct 31 23:22:38 localhost avahi-daemon[798]: Registering new address record for 10.1.252.248 on eno16777736.IPv4.
    Oct 31 23:22:38 localhost Keepalived_healthcheckers[11286]: Netlink reflector reports IP 10.1.252.248 added
[root@localhost keepalived]# ip a l
    ......

    eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:e8:7c:bc brd ff:ff:ff:ff:ff:ff
    inet 10.1.252.34/16 brd 10.1.255.255 scope global eno16777736
       valid_lft forever preferred_lft forever
    inet 10.1.252.248/16 scope global secondary eno16777736
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fee8:7cbc/64 scope link 
       valid_lft forever preferred_lft forever

    ......

再次查看主机1的IP地址(可以在两台主机间多次启动和关闭服务,多次测试)。

[root@localhost keepalived]# ip a
    ......

    eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:0e:27:cd brd ff:ff:ff:ff:ff:ff
    inet 10.1.252.55/16 brd 10.1.255.255 scope global eno16777736
       valid_lft forever preferred_lft forever
    inet 10.1.252.246/16 scope global secondary eno16777736
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe0e:27cd/64 scope link 
       valid_lft forever preferred_lft forever

    ......

3、创建通知脚本示例

以下操作主机1和主机2都一样操作

1)在主机1的/etc/keepalived/目录中新建一个脚本notify.sh,内容如下

[root@localhost keepalived]# vim notify.sh

#!/bin/bash
#
contact='root@localhost'
notify() {
        mailsubject="$(hostname) to be $1, vip floating"
        mailbody="$(date +'%F %T'): vrrp transition, $(hostname) changed to be $1"
        echo "$mailbody" | mail -s "$mailsubject" $contact
}

case $1 in
master)
        notify master
        ;;
backup)
        notify backup
        ;;
fault)
        notify fault
        ;;
*)
        echo "Usage: $(basename $0) {master|backup|fault}"
        exit 1
        ;;
esac

[root@localhost keepalived]# chmod +x notify.sh  (给脚本执行权限)

2)在keepalived.conf文件中设置脚本调用

[root@localhost keepalived]# vim keepalived.conf
    ...... (省略部分重复内容,以免篇幅过长)

    vrrp_instance VI_51 {
            ......
        }
        virtual_ipaddress {
            10.1.252.246/16 dev eno16777736
        }

        notify_master "/etc/keepalived/notify.sh master"
        notify_backup "/etc/keepalived/notify.sh backup"
        notify_fault "/etc/keepalived/notify.sh fault"  
    }

......

自此,通知脚本及配置完成,之后keepalived服务的启动和关闭都会有邮件通知管理员了。

补充:以lvs-dr模式用keepalived做一个高可用的nginx服务

keepalived高可用实例

实验环境VMware虚拟机,K1和K2是cento 7,W1和W2是centos 6.8,自行按照拓扑图,给每台主机配置好IP地址,并且要保证K1和K2的时间同步

1、director内主机的配置

(1)K1主机(master)的设置

1)keepalived.conf文件的配置如下

[root@node1 ~]# yum -y install keepalived (安装keepalived)
[root@localhost keepalived]# vim keepalived.conf

! Configuration File for keepalived

global_defs {
   notification_email {
     root@localhost
   }
   notification_email_from keepalived@localhost
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id node1
   vrrp_mcast_group4 224.0.100.51
}

vrrp_script chk_nginx {
   script "killall -0 nginx && exit 0 || exit 1"
   interval 1
   weight -5
}

vrrp_instance VI_51 {
    state MASTER
    interface eno16777736
    virtual_router_id 210
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass e8c59269
    }
    virtual_ipaddress {
        10.1.252.246/16 dev eno16777736
    }
    track_script {
        chk_nginx
    }
}

2)按照nginx并配置反代功能

安装:

[root@localhost ~]# rpm -ih nginx-1.10.0-1.el7.ngx.x86_64.rpm (nginx的RPM包可自行下载)
warning: nginx-1.10.0-1.el7.ngx.x86_64.rpm: Header V4 RSA/SHA1 Signature, key ID 7bd9bf62: NOKEY
################################# [100%]
Updating / installing...
################################# [100%]
----------------------------------------------------------------------

Thanks for using nginx!

Please find the official documentation for nginx here:
* http://nginx.org/en/docs/

Commercial subscriptions for nginx are available on:
* http://nginx.com/products/

----------------------------------------------------------------------

配置:

[root@localhost ~]# cd /etc/nginx/
[root@localhost nginx]# vim nginx.conf
http {
    ......  (在http段添加以下内容)

    upstream websrvs {
        server 10.1.252.146;
        server 10.1.252.148;
    }   

    ......
}

[root@localhost nginx]# vim conf.d/default.conf 
......

location / {
    root   /usr/share/nginx/html;
    proxy_pass http://websrvs;   (在第一个location中添加此行内容)
    index  index.html index.htm;
}

......

启动:

[root@localhost ~]# systemctl start nginx

3)安装ipvsadm

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

(2)K2主机(backup)的配置

1)keepalived.conf文件的配置如下

[root@node1 ~]# yum -y install keepalived (安装keepalived)
[root@localhost keepalived]# vim keepalived.conf

! Configuration File for keepalived

global_defs {
   notification_email {
     root@localhost
   }
   notification_email_from keepalived@localhost
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id node1
   vrrp_mcast_group4 224.0.100.51
}

vrrp_script chk_nginx {
   script "killall -0 nginx && exit 0 || exit 1"
   interval 1
   weight -5
}

vrrp_instance VI_51 {
    state BACKUP
    interface eno16777736
    virtual_router_id 210
    priority 98
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass e8c59269
    }
    virtual_ipaddress {
        10.1.252.246/16 dev eno16777736
    }
    track_script {
        chk_nginx
    }
}

后面的2、3步的配置同K1一样

2、web服务器的配置

(1)W1的配置

1)安装httpd服务

[root@localhost ~]# yum -y install httpd

2)新建一个网页

[root@localhost ~]# vim /var/www/html/index.html
web server 1

3)启动httpd服务

[root@localhost ~]# service httpd start
[root@localhost ~]# curl 10.1.252.146
web server 1    (测试正常)

4)修改内核参数,禁止广播响应

[root@localhost ~]# echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore 
[root@localhost ~]# echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce
[root@localhost ~]# echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore
[root@localhost ~]# echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce

(2)W2的配置

1)安装httpd服务

[root@localhost ~]# yum -y install httpd

2)新建一个网页

[root@localhost ~]# vim /var/www/html/index.html
web server 2

3)启动httpd服务

[root@localhost ~]# service httpd start
[root@localhost ~]# curl 10.1.252.148
web server 2    (测试正常)

4)修改内核参数,禁止广播响应

[root@localhost ~]# echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore 
[root@localhost ~]# echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce
[root@localhost ~]# echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore
[root@localhost ~]# echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce

3、测试

1)先启动W2主机的keepalived服务,查看IP地址,并访问

[root@localhost ~]# systemctl start keepalived.service
[root@localhost ~]# ip a l
......

 eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:e8:7c:bc brd ff:ff:ff:ff:ff:ff
    inet 10.1.252.34/16 brd 10.1.255.255 scope global eno16777736
       valid_lft forever preferred_lft forever
    inet 10.1.252.246/16 scope global secondary eno16777736
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fee8:7cbc/64 scope link 
       valid_lft forever preferred_lft forever

......

[root@localhost ~]# for i in {0..9};do curl http://10.1.252.246 ;done (正常访问)
web server 2
web server 1
web server 2
web server 1
web server 2
web server 1
web server 2
web server 1
web server 2
web server 1

2)关闭W2主机的keepalived服务,并启动W1主机的keepalived服务,查看IP地址并访问

[root@localhost keepalived]# ip a
......

eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:0e:27:cd brd ff:ff:ff:ff:ff:ff
inet 10.1.252.55/16 brd 10.1.255.255 scope global eno16777736
   valid_lft forever preferred_lft forever
inet 10.1.252.246/16 scope global secondary eno16777736
   valid_lft forever preferred_lft forever
inet6 fe80::20c:29ff:fe0e:27cd/64 scope link 
   valid_lft forever preferred_lft forever

......

[root@localhost ~]# for i in {0..9};do curl http://10.1.252.246 ;done (依然正常访问)
web server 2
web server 1
web server 2
web server 1
web server 2
web server 1
web server 2
web server 1
web server 2
web server 1

原创文章,作者:pao,如若转载,请注明出处:http://www.178linux.com/56834

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