keepalived

keepalived高可用

目录

• 1. keepalived简介
  • 1.1 keepalived是什么？
  • 1.2 keepalived的重要功能
  • 1.3 keepalived高可用故障转移的原理
  • 1.4 keepalived原理
    • 1.4.1 keepalived高可用构架图
    • 1.4.2 keepalived工作原理描述
• 4. keepalived实现nginx负载均衡机高可用
  • 4.1 keepalived安装
  • 4.2 在主备机上分别安装nginx
  • 4.3 keepalived配置
    • 4.3.1 配置主keepalived
    • 4.3.2 配置备keepalived
    • 4.3.3 查看VIP在哪里
  • 4.4 修改内核参数，开启监听VIP功能
  • 4.5 让keepalived监控nginx负载均衡机
  • 4.6 配置keepalived加入监控脚本的配置
• 模拟故障

1. keepalived简介

1.1 keepalived是什么？

Keepalived 软件起初是专为LVS负载均衡软件设计的，用来管理并监控LVS集群系统中各个服务节点的状态，后来又加入了可以实现高可用的VRRP功能。因此，Keepalived除了能够管理LVS软件外，还可以作为其他服务（例如：Nginx、Haproxy、MySQL等）的高可用解决方案软件。

Keepalived软件主要是通过VRRP协议实现高可用功能的。VRRP是Virtual Router RedundancyProtocol(虚拟路由器冗余协议）的缩写，VRRP出现的目的就是为了解决静态路由单点故障问题的，它能够保证当个别节点宕机时，整个网络可以不间断地运行。所以，Keepalived 一方面具有配置管理LVS的功能，同时还具有对LVS下面节点进行健康检查的功能，另一方面也可实现系统网络服务的高可用功能。

Keepalived官网：http://www.keepalived.org/

1.2 keepalived的重要功能

keepalived 有三个重要的功能，分别是：

• 管理LVS负载均衡软件
• 实现LVS集群节点的健康检查
• 作为系统网络服务的高可用性（failover）

1.3 keepalived高可用故障转移的原理

Keepalived 高可用服务之间的故障切换转移，是通过 VRRP (Virtual Router Redundancy Protocol ,虚拟路由器冗余协议）来实现的。

在 Keepalived 服务正常工作时，主 Master 节点会不断地向备节点发送（多播的方式）心跳消息，用以告诉备 Backup 节点自己还活看，当主 Master 节点发生故障时，就无法发送心跳消息，备节点也就因此无法继续检测到来自主 Master 节点的心跳了，于是调用自身的接管程序，接管主 Master 节点的 IP 资源及服务。而当主 Master 节点恢复时，备 Backup 节点又会释放主节点故障时自身接管的IP资源及服务，恢复到原来的备用角色。
那么，什么是VRRP呢？
VRRP ,全 称 Virtual Router Redundancy Protocol ,中文名为虚拟路由冗余协议 ，VRRP的出现就是为了解决静态踣甶的单点故障问题，VRRP是通过一种竞选机制来将路由的任务交给某台VRRP路由器的。

1.4 keepalived原理

1.4.1 keepalived高可用构架图

1.4.2 keepalived工作原理描述

Keepalived高可用对之间是通过VRRP通信的，因此，我们从 VRRP开始了解起：

1. VRRP,全称 Virtual Router Redundancy Protocol,中文名为虚拟路由冗余协议，VRRP的出现是为了解决静态路由的单点故障。
2. VRRP是通过一种竟选协议机制来将路由任务交给某台 VRRP路由器的。
3. VRRP用 IP多播的方式（默认多播地址（224.0_0.18))实现高可用对之间通信。
4. 工作时主节点发包，备节点接包，当备节点接收不到主节点发的数据包的时候，就启动接管程序接管主节点的开源。备节点可以有多个，通过优先级竞选，但一般 Keepalived系统运维工作中都是一对。
5. VRRP使用了加密协议加密数据，但Keepalived官方目前还是推荐用明文的方式配置认证类型和密码。

介绍完 VRRP,接下来我再介绍一下Keepalived服务的工作原理：
Keepalived高可用是通过 VRRP 进行通信的， VRRP是通过竞选机制来确定主备的，主的优先级高于备，因此，工作时主会优先获得所有的资源，备节点处于等待状态，当主挂了的时候，备节点就会接管主节点的资源，然后顶替主节点对外提供服务。
在 Keepalived 服务之间，只有作为主的服务器会一直发送 VRRP 广播包,告诉备它还活着，此时备不会枪占主，当主不可用时，即备监听不到主发送的广播包时，就会启动相关服务接管资源，保证业务的连续性.接管速度最快可以小于1秒。

4. keepalived实现nginx负载均衡机高可用

环境说明

系统信息	主机名	IP
centos8	master	192.168.29.140
centos8	slave	192.168.29.141
本次高可用虚拟IP（VIP）地址暂定为192.168.29.250

4.1 keepalived安装

配置主keepalived

[root@master ~]# systemctl stop firewalld
[root@master ~]# systemctl disable firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.

[root@master ~]# getenforce 
Disabled
[root@master ~]# curl -o /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-vault-8.5.2111.repo
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  2495  100  2495    0     0  20966      0 --:--:-- --:--:-- --:--:-- 20966
[root@master ~]# yum install -y https://mirrors.aliyun.com/epel/epel-release-latest-8.noarch.rpm
Failed to set locale, defaulting to C.UTF-8
Repository extras is listed more than once in the configuration
CentOS-8.5.2111 - Base - mirrors.aliyun.com       1.6 MB/s | 4.6 MB     00:02    
CentOS-8.5.2111 - Extras - mirrors.aliyun.com     206 kB/s |  10 kB     00:00    
CentOS-8.5.2111 - AppStream - mirrors.aliyun.com  1.1 MB/s | 8.4 MB     00:07    
epel-release-latest-8.noarch.rpm                  301 kB/s |  24 kB     00:00    
Dependencies resolved.
==================================================================================
 Package              Architecture   Version           Repository            Size
==================================================================================
Installing:
 epel-release         noarch         8-17.el8          @commandline          24 k

Transaction Summary
==================================================================================
Install  1 Package

Total size: 24 k
Installed size: 34 k
Downloading Packages:
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                          1/1 
  Installing       : epel-release-8-17.el8.noarch                             1/1 
  Running scriptlet: epel-release-8-17.el8.noarch                             1/1 
Many EPEL packages require the CodeReady Builder (CRB) repository.
It is recommended that you run /usr/bin/crb enable to enable the CRB repository.

  Verifying        : epel-release-8-17.el8.noarch                             1/1 
Installed products updated.

Installed:
  epel-release-8-17.el8.noarch                                                    

Complete!
[root@master ~]# sed -i 's|^#baseurl=https://download.example/pub|baseurl=https://mirrors.aliyun.com|' /etc/yum.repos.d/epel*
[root@master ~]# sed -i 's|^metalink|#metalink|' /etc/yum.repos.d/epel*
[root@master ~]# yum -y install keepalived vim wget gcc gcc-c++

同同样的方法在备服务器上安装keepalived

[root@backup ~]# systemctl stop firewalld
[root@backup ~]# systemctl disable firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@backup ~]# getenforce 
Disabled
[root@backup ~]# curl -o /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-vault-8.5.2111.repo
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  2495  100  2495    0     0  20966      0 --:--:-- --:--:-- --:--:-- 20966
[root@backup ~]# yum install -y https://mirrors.aliyun.com/epel/epel-release-latest-8.noarch.rpm
Failed to set locale, defaulting to C.UTF-8
Repository extras is listed more than once in the configuration
CentOS-8.5.2111 - Base - mirrors.aliyun.com       1.6 MB/s | 4.6 MB     00:02    
CentOS-8.5.2111 - Extras - mirrors.aliyun.com     206 kB/s |  10 kB     00:00    
CentOS-8.5.2111 - AppStream - mirrors.aliyun.com  1.1 MB/s | 8.4 MB     00:07    
epel-release-latest-8.noarch.rpm                  301 kB/s |  24 kB     00:00    
Dependencies resolved.
==================================================================================
 Package              Architecture   Version           Repository            Size
==================================================================================
Installing:
 epel-release         noarch         8-17.el8          @commandline          24 k

Transaction Summary
==================================================================================
Install  1 Package

Total size: 24 k
Installed size: 34 k
Downloading Packages:
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing        :                                                          1/1 
  Installing       : epel-release-8-17.el8.noarch                             1/1 
  Running scriptlet: epel-release-8-17.el8.noarch                             1/1 
Many EPEL packages require the CodeReady Builder (CRB) repository.
It is recommended that you run /usr/bin/crb enable to enable the CRB repository.

  Verifying        : epel-release-8-17.el8.noarch                             1/1 
Installed products updated.

Installed:
  epel-release-8-17.el8.noarch                                                    

Complete!
[root@backup ~]# sed -i 's|^#baseurl=https://download.example/pub|baseurl=https://mirrors.aliyun.com|' /etc/yum.repos.d/epel*
[root@backup ~]# sed -i 's|^metalink|#metalink|' /etc/yum.repos.d/epel*
[root@backup ~]# yum -y install keepalived vim wget gcc gcc-c++

4.2 在主备机上分别安装nginx

在master上安装nginx

[root@master ~]#yum -y install nginx
[root@master ~]# systemctl restart nginx
[root@master ~]# systemctl enable nginx
Created symlink /etc/systemd/system/multi-user.target.wants/nginx.service → /usr/lib/systemd/system/nginx.service.
[root@master ~]# ss -antl
State    Recv-Q   Send-Q     Local Address:Port     Peer Address:Port   Process   
LISTEN   0        128              0.0.0.0:80            0.0.0.0:*                
LISTEN   0        128              0.0.0.0:22            0.0.0.0:*                
LISTEN   0        128                 [::]:80               [::]:*                
LISTEN   0        128                 [::]:22               [::]:*                
[root@master ~]# cd /usr/share/nginx/html/
[root@master html]# echo "master" > index.html

在slave上安装nginx

[root@backup ~]#yum -y install backup
[root@backup ~]# systemctl restart nginx
[root@backup ~]# systemctl enable nginx
Created symlink /etc/systemd/system/multi-user.target.wants/nginx.service → /usr/lib/systemd/system/nginx.service.
[root@backup ~]# ss -antl
State    Recv-Q   Send-Q     Local Address:Port     Peer Address:Port   Process   
LISTEN   0        128              0.0.0.0:80            0.0.0.0:*                
LISTEN   0        128              0.0.0.0:22            0.0.0.0:*                
LISTEN   0        128                 [::]:80               [::]:*                
LISTEN   0        128                 [::]:22               [::]:*                
[root@backup ~]# cd /usr/share/nginx/html/
[root@backup html]# echo "slave" > index.html

在浏览器上访问试试，确保master上的nginx服务能够正常访问

4.3 keepalived配置

4.3.1 配置主keepalived

[root@master ~]# cd /etc/keepalived/
[root@master keepalived]# vim keepalived.conf 
! Configuration File for keepalived

global_defs {
        router_id mr01
}

vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
   virtual_ipaddress {
        192.168.29.250
    }
}

virtual_server 192.168.29.250 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.29.140 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.29.141 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}
[root@master keepalived]# systemctl restart keepalived.service 
[root@master keepalived]# systemctl enable keepalived.service
Created symlink /etc/systemd/system/multi-user.target.wants/keepalived.service → /usr/lib/systemd/system/keepalived.service.

4.3.2 配置备keepalived

[root@backup ~]# cd /etc/keepalived/
[root@backup keepalived]# cp keepalived.conf keepalived.conf.bak
[root@backup keepalived]# vim keepalived.conf
! Configuration File for keepalived

global_defs {
        router_id mr02
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.29.250
    }
}

virtual_server 192.168.29.250 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.29.140 80 {
        weight 1
            TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.29.141 80 {
        weight 1
        TCP_CHECK { 
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}
[root@backup keepalived]# systemctl restart keepalived.service
[root@backup keepalived]# systemctl enable keepalived.service
Created symlink /etc/systemd/system/multi-user.target.wants/keepalived.service → /usr/lib/systemd/system/keepalived.service.

4.3.3 查看VIP在哪里

在master上查看

[root@master ~]# 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 fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:f0:df:ce brd ff:ff:ff:ff:ff:ff
    inet 192.168.29.140/24 brd 192.168.29.255 scope global dynamic noprefixroute ens33
       valid_lft 1402sec preferred_lft 1402sec
    inet 192.168.29.250/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::3cf0:13fe:3b43:3ccd/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

在backup上查看

[root@backup ~]# 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 fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:b9:bd:f9 brd ff:ff:ff:ff:ff:ff
    inet 192.168.29.141/24 brd 192.168.29.255 scope global dynamic noprefixroute ens33
       valid_lft 1444sec preferred_lft 1444sec
    inet6 fe80::9a33:ce06:9305:f665/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

4.4 修改内核参数，开启监听VIP功能

此步可做可不做，该功能可用于仅监听VIP的时候

4.5 让keepalived监控nginx负载均衡机

keepalived通过控制nginx负载均衡的状态
在master上编写脚本

[root@master ~]# mkdir /scripts
[root@master ~]# cd /scripts/
[root@master scripts]# vim check.sh
#!/bin/bash
nginx_status=`ps -ef | grep -v "grep" | grep "nginx" | wc -l`
if [ $nginx_status -lt 1 ];then
        systemctl stop keepalived
fi
[root@master scripts]# chmod +x check.sh 
[root@master scripts]# vim notify.sh
#!/bin/bash
VIP=$2
sendmail () { 
	subject="${VIP}'s server keepalived state is translate"
	content="`date +'%F %T'`: `hostname`'s state change to master"
	echo $content | mail -s "$subject" 3215547886@qq.com
}
case "$1" in 
  master)
	nginx_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bnginx\b'|wc -l)
	if [ $nginx_status -lt 1 ];then
		systemctl start nginx
	fi
	sendmail
   ;;
   backup)								        
	nginx_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bnginx\b'|wc -l)
	if [ $nginx_status -gt 0 ];then
		systemctl stop nginx
	fi
   ;;
   *) 
	echo "Usage:$0 master|backup VIP"
   ;;
esac
[root@master scripts]# chmod +x notify.sh

在backup上编写脚本

[root@backup ~]# mkdir /scripts
[root@backup ~]# cd /scripts/
[root@backup scripts]# scp root@192.168.29.140:/scripts/check.sh .
The authenticity of host '192.168.29.140 (192.168.29.140)' can't be established.
ECDSA key fingerprint is SHA256:tGhqSo3u9wWuDd+55Xaw4UgDdkolb4FOhqKtT398KTA.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '192.168.29.140' (ECDSA) to the list of known hosts.
root@192.168.29.140's password: 
check.sh                                        100%  144   111.3KB/s   00:00    
[root@backup scripts]# scp root@192.168.29.140:/scripts/notify.sh .
root@192.168.29.140's password: 
notify.sh                                       100%  605   555.5KB/s   00:00    
[root@backup scripts]# 

4.6 配置keepalived加入监控脚本的配置

配置主keepalived

[root@master scripts]# cat /etc/keepalived/keepalived.conf 

! Configuration File for keepalived

global_defs {
        router_id mr01
}
vrrp_script nginx_check { 
    script "/scripts/check.sh"
    interval 10
    weight -20
}

vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.29.250
    }
    track_script { 
        nginx_check
    }
    notify_master "/scripts/notify.sh master 192.168.29.250"
    notify_backup "/scripts/notify.sh backup 192.168.29.250"
}

virtual_server 192.168.29.250 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.29.140 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.29.141 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}
[root@master scripts]# systemctl restart keepalived.service

配置backup的keepalived

[root@backup scripts]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
        router_id mr02
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.29.250
    }
    notify_master "/scripts/notify.sh master 192.168.29.250"
    notify_backup "/scripts/notify.sh backup 192.168.29.250"
}

virtual_server 192.168.29.250 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.29.140 80 {
        weight 1
            TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.29.141 80 {
        weight 1
        TCP_CHECK { 
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

[root@backup scripts]# systemctl restart keepalived.service    

模拟故障

[root@master ~]# systemctl restart nginx
[root@master ~]# systemctl enable nginx
[root@master ~]# ss -antl
State    Recv-Q   Send-Q     Local Address:Port     Peer Address:Port   Process   
LISTEN   0        128              0.0.0.0:80            0.0.0.0:*                
LISTEN   0        128              0.0.0.0:22            0.0.0.0:*                
LISTEN   0        128                 [::]:80               [::]:*                
LISTEN   0        128                 [::]:22               [::]:*                
[root@master ~]# 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 fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:f0:df:ce brd ff:ff:ff:ff:ff:ff
    inet 192.168.29.140/24 brd 192.168.29.255 scope global dynamic noprefixroute ens33
       valid_lft 1672sec preferred_lft 1672sec
    inet 192.168.29.250/24 brd 192.168.29.255 scope global secondary noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::3cf0:13fe:3b43:3ccd/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

[root@backup ~]# 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 fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:b9:bd:f9 brd ff:ff:ff:ff:ff:ff
    inet 192.168.29.141/24 brd 192.168.29.255 scope global dynamic noprefixroute ens33
       valid_lft 1163sec preferred_lft 1163sec
    inet 192.168.29.250/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::9a33:ce06:9305:f665/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

[root@master ~]# systemctl restart nginx
[root@master ~]# systemctl enable nginx
[root@master ~]# ss -antl
State    Recv-Q   Send-Q     Local Address:Port     Peer Address:Port   Process   
LISTEN   0        128              0.0.0.0:80            0.0.0.0:*                
LISTEN   0        128              0.0.0.0:22            0.0.0.0:*                
LISTEN   0        128                 [::]:80               [::]:*                
LISTEN   0        128                 [::]:22               [::]:*                
[root@master ~]# 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 fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:f0:df:ce brd ff:ff:ff:ff:ff:ff
    inet 192.168.29.140/24 brd 192.168.29.255 scope global dynamic noprefixroute ens33
       valid_lft 1672sec preferred_lft 1672sec
    inet 192.168.29.250/24 brd 192.168.29.255 scope global secondary noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::3cf0:13fe:3b43:3ccd/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever