Keepalived_keepalived arp-优快云博客

本文链接：https://blog.youkuaiyun.com/hwjos/article/details/110483848

keepalived简介

keepalived介绍
Keepalived是基于vrrp协议的一款高可用软件。它的作用是检测服务器的状态，如果有一台web服务器

宕机，或工作出现故障，Keepalived将检测到，并将有故障的服务器从系统中剔除，同时使用其他服务器

代替该服务器的工作，当服务器工作正常后Keepalived自动将服务器加入到服务器群中，这些工作全部自

动完成，不需要人工干涉，需要人工做的只是修复故障的服务器。

keepalive结构图：
在这里插入图片描述
Keepalvied的工作原理
Keepalived工作在TCP/IP 参考模型的三层、四层、五层，也就是分别为：网络层，

传输层和应用层，根据TCP、IP参数模型隔层所能实现的功能，Keepalived运行机制如下：
在网络层：我们知道运行这4个重要的协议，互联网络IP协议，互联网络可控制报文协议ICMP、地址转换协议ARP、反向地址转换协议RARP，在网络层Keepalived在网络层采用最常见的工作方式是通过ICMP协议向服务器集群中的每一个节点发送一个ICMP数据包(有点类似与Ping的功能)，如果某个节点没有返回响应数据包，那么认为该节点发生了故障，Keepalived将报告这个节点失效，并从服务器集群中剔除故障节点。
在传输层：提供了两个主要的协议：传输控制协议TCP和用户数据协议UDP，传输控制协议TCP可以提供可靠的数据输出服务、IP地址和端口，代表TCP的一个连接端，要获得TCP服务，需要在发送机的一个端口和接收机的一个端口上建立连接，而Keepalived在传输层里利用了TCP协议的端口连接和扫描技术来判断集群节点的端口是否正常，比如对于常见的WEB服务器80端口。或者SSH服务22端口，Keepalived一旦在传输层探测到这些端口号没有数据响应和数据返回，就认为这些端口发生异常，然后强制将这些端口所对应的节点从服务器集群中剔除掉。

在应用层：可以运行FTP，TELNET，SMTP，DNS等各种不同类型的高层协议，Keepalived的运行方式也更加全面化和复杂化，用户可以通过自定义Keepalived工作方式，例如：可以通过编写程序或者脚本来运行Keepalived，而Keepalived将根据用户的设定参数检测各种程序或者服务是否允许正常，如果Keepalived的检测结果和用户设定的不一致时，Keepalived将把对应的服务器从服务器集群中剔除

配置Keepalived

配置环境

已关闭防火墙、selinux；

环境说明

角色	IP地址	系统版本
Client	192.168.236.130	Redhat 8
MASTER	192.168.236.131	Redhat 8
SLAVE	192.168.86.138	Redhat 8
rs1	192.168.236.135	Redhat 8
rs2	192.168.236.132	Redhat 8

配置步骤

在master和backup两主机上分别配置网络源、安装epel-release，并安装Keepalived和MySQL

//配置yum源和ep源
curl -o /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-8.repo
sed -i -e '/mirrors.cloud.aliyuncs.com/d' -e '/mirrors.aliyuncs.com/d' /etc/yum.repos.d/CentOS-Base.repo

yum install -y https://mirrors.aliyun.com/epel/epel-release-latest-8.noarch.rpm
sed -i 's|^#baseurl=https://download.fedoraproject.org/pub|baseurl=https://mirrors.aliyun.com|' /etc/yum.repos.d/epel*
sed -i 's|^metalink|#metalink|' /etc/yum.repos.d/epel*

在RS端安装httpd服务

[root@rs1 ~]# yum -y install httpd
[root@rs1 ~]# systemctl enable --now httpd
[root@rs1 ~]# echo "web1" > /var/www/html/index.html

[root@RS2 ~]# yum -y install httpd
[root@RS2 ~]# systemctl enable --now httpd
[root@RS2 ~]# echo "web2" > /var/www/html/index.html

配置负载均衡

//配置MASTER的IP地址，并重启网卡
[root@MASTER ~]# vi /etc/sysconfig/network-scripts/ifcfg-ens160 
TYPE=Ethernet
BOOTPROTO=static
ONBOOT=yes
NAME=ens160
DEVICE=ens160
IPADDR=192.168.236.131
PREFIX=24
GATEWAY=192.168.236.2
DNS1=114.114.114.114
[root@MASTER ~]# ifdown ens160;ifup ens160


[root@RS1 ~]# vi /etc/sysctl.conf
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2
[root@RS1 ~]#  sysctl -p
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2

//在RS端配置内核参数和IP地址
[root@RS1 ~]# vi /etc/sysconfig/network-scripts/ifcfg-ens160 

TYPE=Ethernet
BOOTPROTO=static
ONBOOT=yes
NAME=ens160
DEVICE=ens160
IPADDR0=192.168.236.135
PREFIX0=24
GATEWAY0=192.168.236.2
IPADDR1=192.168.236.250
PREFIX1=24
DNS1=114.114.114.114
[root@RS1 ~]# ifdown ens160;ifup ens160


[root@SR2 ~]# vi /etc/sysctl.conf
[root@RS2 ~]# sysctl -p
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2

[root@SR2 ~]# vi /etc/sysconfig/network-scripts/ifcfg-ens160
TYPE="Ethernet"
BOOTPROTO="static"
IPADDR0=192.168.236.136
PREFIX0=24
GATEWAY0=192.168.236.2
IPADDR1=192.168.236.250
PREFIX1=24
NAME="ens160"
DEVICE="ens160"
ONBOOT="yes"
DNS1=114.114.114.114
[root@RS2 ~]# ifdown ens160; ifup ens160

//在MASTER端添加负载均衡规则
[root@MASTER ~]# ipvsadm -A -t 192.168.236.250 -s rr
[root@MASTER ~]# ipvsadm -a -t 192.168.236.250:80 -r 192.168.236.135:80 -g
[root@MASTER ~]# ipvsadm -a -t 192.168.236.250:80 -r 192.168.236.136:80 -g

[root@MASTER ~]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.236.250:80 rr
  -> 192.168.236.135:80           Route   1      0          0         
  -> 192.168.236.136:80           Route   1      0          0

////关闭防火墙和SELINUX
[root@localhost ~]# systemctl disable firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@localhost ~]# vim /etc/selinux/config 
reboot 

//配置SLAVE的IP地址并重启网卡
[root@SLAVE ~]# vim /etc/sysconfig/network-scripts/ifcfg-ens160

BOOTPROTO=static
ONBOOT=yes
NAME=ens160
DEVICE=ens160
IPADDR=192.168.236.132
PREFIX=24
GATEWAY=192.168.236.2
DNS1=114.114.114.114

[root@SLAVE ~]# ifdown ens160;ifup ens160



//在SLAVE端添加负载均衡规则
[root@SLAVE ~]# ipvsadm -A -t 192.168.236.250:80 -s rr
[root@SLAVE ~]# ipvsadm -a -t 192.168.236.250:80 -r 192.168.236.135:80 -g
[root@SLAVE ~]# ipvsadm -a -t 192.168.236.250:80 -r 192.168.236.136:80 -g
[root@SLAVE ~]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.236.250:80 rr
  -> 192.168.236.135:80           Route   1      0          0         
  -> 192.168.236.136:80           Route   1      0          0


//关闭防火墙和SELINUX
[root@localhost ~]# systemctl disable firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@localhost ~]# vim /etc/selinux/config 
[root@localhost ~]# reboot

配置Keepalived

//配置主Keepavlied 并安装Keepalived
[root@MASTER ~]# yum -y install keepalived

[root@MASTER ~]#  cp /etc/keepalived/keepalived.conf{,-bak}
[root@MASTER ~]# vi /etc/keepalived/keepalived.conf
[root@MASTER keepalived]# vi keepalived.conf

! Configuration File for keepalived

global_defs {
   router_id lb01
}

vrrp_instance VI_1 {
    state MASTER
    interface ens160
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass wangqing
    }
    virtual_ipaddress {
        192.168.236.250
    }
}

virtual_server 192.168.236.250 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.236.135 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.236.136 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}
[root@MASTER keepalived]# systemctl enable --now keepalived

在SLAVE端上安装Keepalived

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

[root@localhost ~]# systemctl disable firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@localhost ~]# vim /etc/selinux/config 
[root@localhost ~]# reboot

//配置备Keepavlied
[root@SLAVE ~]# cp /etc/keepalived/keepalived.conf{,-bak}
[root@SLAVE keepalived]# vi keepalived.conf

! Configuration File for keepalived

global_defs {
   router_id lb02
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens160
    virtual_router_id 51
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass redhat
    }
    virtual_ipaddress {
        192.168.236.250
    }
}

virtual_server 192.168.236.250 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.236.135 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.236.136 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

//查看VIP在哪里
[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: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:54:83:50 brd ff:ff:ff:ff:ff:ff
    inet 192.168.236.131/24 brd 192.168.236.255 scope global noprefixroute ens160
       valid_lft forever preferred_lft forever
    inet 192.168.236.250/32 scope global ens160
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe54:8350/64 scope link 
       valid_lft forever preferred_lft forever

[root@SLAVE ~]# 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: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:e2:ff:58 brd ff:ff:ff:ff:ff:ff
    inet 192.168.236.132/24 brd 192.168.236.255 scope global noprefixroute ens160
       valid_lft forever preferred_lft forever
    inet 192.168.236.250/32 scope global ens160
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fee2:ff58/64 scope link 
       valid_lft forever preferred_lft forever

//验证

//关闭MASTER端上的Keepavlied，模拟MASTER宕机
[root@MASTER ~]# systemctl stop keepalived
[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: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:54:83:50 brd ff:ff:ff:ff:ff:ff
    inet 192.168.236.131/24 brd 192.168.236.255 scope global noprefixroute ens160
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe54:8350/64 scope link 
       valid_lft forever preferred_lft forever

//在SLAVE端上查看是否有VIP
[root@SLAVE ~]# 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: ens160: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:e2:ff:58 brd ff:ff:ff:ff:ff:ff
    inet 192.168.236.132/24 brd 192.168.236.255 scope global noprefixroute ens160
       valid_lft forever preferred_lft forever
    inet 192.168.236.250/32 scope global ens160
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fee2:ff58/64 scope link 
       valid_lft forever preferred_lft forever

//验证
[root@localhost ~]# curl http://192.168.236.250
web2