keepalived高可用

最新推荐文章于 2024-03-08 00:00:58 发布

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Keepalived通过VRRP协议提供高可用性，防止单点故障。它管理LVS负载均衡，进行健康检查，并在主节点故障时自动切换。VRRP是一种竞选机制，确保路由任务在多台路由器间无缝转移。配置中，Keepalived设置虚拟IP，监控LVS节点，并通过脚本进行故障转移。在模拟故障场景下，备用节点接管服务，确保服务不间断。

keepalived

keepalivlived是什么

什么是Keepalived呢，keepalived观其名可知，保持存活，在网络里面就是保持在线了，也就是所谓的高可用或热备，用来防止单点故障(单点故障是指一旦某一点出现故障就会导致整个系统架构的不可用)的发生，那说到keepalived时不得不说的一个协议就是VRRP协议，可以说这个协议就是keepalived实现的基础
keepalived的重要功能

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）

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。

keepalived高可用架构图
在这里插入图片描述

keepalived默认配置文件

keepalived的主配置文件是/etc/keepalived/keepalived.conf

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

global_defs {       //全局配置
   notification_email {     //定义报警收件人邮件地址
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc    //定义报警发件人邮箱
   smtp_server 192.168.200.1    //邮箱服务器地址
   smtp_connect_timeout 30      //定义邮箱超时时间
   router_id LVS_DEVEL          //定义路由标识信息，同局域网内唯一
   vrrp_skip_check_adv_addr
   vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_instance VI_1 {        //定义实例
    state MASTER            //指定keepalived节点的初始状态，可选值为MASTER|BACKUP
    interface eth0          //VRRP实例绑定的网卡接口，用户发送VRRP包
    virtual_router_id 51    //虚拟路由的ID，同一集群要一致
    priority 100            //定义优先级，按优先级来决定主备角色，优先级越大越优先
    nopreempt               //设置不抢占
    advert_int 1            //主备通讯时间间隔
    authentication {        //配置认证
        auth_type PASS      //认证方式，此处为密码
        auth_pass 1111      //同一集群中的keepalived配置里的此处必须一致，推荐使用8位随机数
    }
    virtual_ipaddress {     //配置要使用的VIP地址
        192.168.200.16
    }
}

virtual_server 192.168.200.16 1358 {    //配置虚拟服务器
    delay_loop 6        //健康检查的时间间隔
    lb_algo rr          //lvs调度算法
    lb_kind NAT         //lvs模式
    persistence_timeout 50      //持久化超时时间，单位是秒
    protocol TCP        //4层协议

    sorry_server 192.168.200.200 1358   //定义备用服务器，当所有RS都故障时用sorry_server来响应客户端

    real_server 192.168.200.2 1358 {    //定义真实处理请求的服务器
        weight 1    //给服务器指定权重，默认为1
        HTTP_GET {
            url {
              path /testurl/test.jsp    //指定要检查的URL路径
              digest 640205b7b0fc66c1ea91c463fac6334d   //摘要信息
            }
            url {
              path /testurl2/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334d
            }
            url {
              path /testurl3/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334d
            }
            connect_timeout 3       //连接超时时间
            nb_get_retry 3          //get尝试次数
            delay_before_retry 3    //在尝试之前延迟多长时间
        }
    }

    real_server 192.168.200.3 1358 {
        weight 1
        HTTP_GET {
            url {
              path /testurl/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334c
            }
            url {
              path /testurl2/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334c
            }
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

配置LVS

关闭防火墙和selinux

[root@R1 ~]# systemctl disable --now firewalld
[root@R1 ~]# setenforce 0
[root@R2 ~]# systemctl disable --now firewalld
[root@R2 ~]# setenforce 0
[root@master ~]# systemctl disable --now firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@master ~]# setenforce 0
[root@slave ~]# systemctl disable --now firewalld
Removed /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@slave ~]# setenforce 0

在调度器上配置VIP和DIP

配置钱先下载所需要的包或者本地源
[root@master ~]# dnf -y install ipvsadm
[root@master ~]# dnf -y install keepalived
[root@slave ~]# dnf -y install ipvsadm
[root@slave ~]# dnf -y install keepalived
[root@master ~]# cat /etc/sysconfig/network-scripts/ifcfg-ens33 
TYPE=Ethernet
BOOTPROTO=static
NAME=ens33
DEVICE=ens33
ONBOOT=yes
IPADDR0=192.168.31.150
PREFIX0=24
IPADDR1=192.168.31.128
PREFIX1=24
GATEWAY=192.168.31.2
DNS1=114.114.114.114
[root@slave ~]# cat /etc/sysconfig/network-scripts/ifcfg-ens33 
TYPE=Ethernet
BOOTPROTO=static
NAME=ens33
DEVICE=ens33
ONBOOT=yes
IPADDR0=192.168.31.150
PREFIX0=24
IPADDR1=192.168.31.138
PREFIX1=24
GATEWAY=192.168.31.2
DNS1=114.114.114.114

在RS上先关闭arp包的通告和响应然后配置RIP和VIP

[root@R1 ~]# dnf -y install net-tools
[root@R2 ~]# dnf -y install net-tools
[root@R1 ~]# sysctl -p
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2
[root@R1 ~]# ifconfig lo:0 192.168.31.150/32 broadcast 192.168.31.150 up
[root@R1 ~]# route add -host 192.168.31.150 dev lo:0
[root@R1 ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.31.2    0.0.0.0         UG    100    0        0 ens33
192.168.31.0    0.0.0.0         255.255.255.0   U     100    0        0 ens33
192.168.31.150  0.0.0.0         255.255.255.255 UH    0      0        0 lo
[root@R1 ~]# 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
    inet 192.168.31.150/0 brd 192.168.31.150 scope global lo:0
       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:ad:28:07 brd ff:ff:ff:ff:ff:ff
    inet 192.168.31.139/24 brd 192.168.31.255 scope global dynamic noprefixroute ens33
       valid_lft 1364sec preferred_lft 1364sec
    inet6 fe80::ad88:29b1:d3a:3039/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever


[root@R2 ~]# sysctl -p
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2
[root@R2 ~]# ifconfig lo:0 192.168.31.150/32 broadcast 192.168.31.150 up
[root@R2 ~]# route add -host 192.168.31.150 dev lo:0
[root@R2 ~]# route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.31.2    0.0.0.0         UG    100    0        0 ens33
192.168.31.0    0.0.0.0         255.255.255.0   U     100    0        0 ens33
192.168.31.150  0.0.0.0         255.255.255.255 UH    0      0        0 lo
[root@R2 ~]# 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
    inet 192.168.31.150/0 brd 192.168.31.150 scope global lo:0
       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:b1:56:f2 brd ff:ff:ff:ff:ff:ff
    inet 192.168.31.140/24 brd 192.168.31.255 scope global dynamic noprefixroute ens33
       valid_lft 1288sec preferred_lft 1288sec
    inet6 fe80::79a5:b0cf:94b2:6de3/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

在调度其上添加规则

[root@master ~]# ipvsadm -A -t 192.168.31.150:80 -s rr
[root@master ~]# ipvsadm -a -t 192.168.31.150:80 -r 192.168.31.139:80 -g
[root@master ~]# ipvsadm -a -t 192.168.31.150:80 -r 192.168.31.140:80 -g
[root@master ~]# ipvsadm -Sn > /etc/sysconfig/ipvsadm
[root@master ~]# ipvsadm -L
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  master:http rr
  -> 192.168.31.139:http          Route   1      0          0         
  -> 192.168.31.140:http          Route   1      0          0   

[root@slave ~]# ipvsadm -A -t 192.168.31.150:80 -s rr
[root@slave ~]# ipvsadm -a -t 192.168.31.150:80 -r 192.168.31.139:80 -g
[root@slave ~]# ipvsadm -a -t 192.168.31.150:80 -r 192.168.31.140:80 -g
[root@slave ~]# ipvsadm -Sn > /etc/sysconfig/ipvsadm
[root@slave ~]# ipvsadm -L
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  czh:http rr
  -> 192.168.31.139:http          Route   1      0          0         
  -> 192.168.31.140:http          Route   1      0          0

配置keepalived主配置文件

配置主keepalived

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

global_defs {
    router_id lb01
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 71
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 121212
    }
    virtual_ipaddress {
        192.168.31.150
    }
}

virtual_server 192.168.31.150 80 {
    delay_loop 6
    lb_algo rr
    lb_kind NAT
    persistence_timeout 50
    protocol TCP

    real_server 192.168.31.139 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
    
     real_server 192.168.31.140 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
[root@master ~]# systemctl start keepalived
[root@master ~]# systemctl enable keepalived

配置keepalived

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

global_defs {
    router_id lb02
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 71
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 121212
    }
    virtual_ipaddress {
        192.168.31.150
    }
}

virtual_server 192.168.31.150 80 {
    delay_loop 6
    lb_algo rr
    lb_kind NAT
    persistence_timeout 50
    protocol TCP

    real_server 192.168.31.139 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
    
     real_server 192.168.31.140 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
[root@slave ~]# vim /etc/keepalived/keepalived.conf
[root@slave ~]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
    router_id lb02
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 71
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 121212
    }
    virtual_ipaddress {
        192.168.31.150
    }
}

virtual_server 192.168.31.150 80 {
    delay_loop 6
    lb_algo rr
    lb_kind NAT
    persistence_timeout 50
    protocol TCP

    real_server 192.168.31.139 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
    
     real_server 192.168.31.140 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
[root@slave ~]#  systemctl start keepalived
[root@slave ~]# systemctl enable keepalived

查看vip

[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:29:28:4f:0e brd ff:ff:ff:ff:ff:ff
    inet 192.168.31.150/24 brd 192.168.31.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.31.128/24 brd 192.168.31.255 scope global secondary noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe28:4f0e/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: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:01:bd:5c brd ff:ff:ff:ff:ff:ff
    inet 192.168.31.150/24 brd 192.168.31.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.31.138/24 brd 192.168.31.255 scope global secondary noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe01:bd5c/64 scope link 
       valid_lft forever preferred_lft forever

让keepalived监控监控LVS的LB

[root@master ~]# mkdir /scripts
[root@master ~]# vim /scripts/notify.sh 
[root@master ~]# cat /scripts/notify.sh 
#!/bin/bash
case "$1" in
    master)
    ipvsadm -R < /etc/sysconfig/ipvsadm
    ;;
    backup)
         ipvsadm -C
    ;;
    *)
          echo "Usage:$0 master|backup"
    ;;
esac
[root@master ~]# chmod +x /scripts/notify.sh

在SLAVE上编写脚本

[root@slave ~]# mkdir /scripts
[root@slave ~]# vim /scripts/notify.sh 
[root@slave ~]# cat /scripts/notify.sh 
#!/bin/bash
case "$1" in
    master)
        ipvsadm -R < /etc/sysconfig/ipvsadm
    ;;
    backup)
        ipvsadm -C
    ;;
    *)
    echo "Usage:$0 master|backup"
;;
esac
[root@slave ~]# chmod +x /scripts/notify.sh

配置keepalived加入故障转移脚本

配置主keepalived

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

global_defs {
    router_id lb01
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 71
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 121212
    }
    virtual_ipaddress {
        192.168.31.150
    }
    notify_master "/scripts/notify.sh master"
    notify_backup "/scripts/notify.sh backup"
}

virtual_server 192.168.31.150 80 {
    delay_loop 6
    lb_algo rr
    lb_kind NAT
    persistence_timeout 50
    protocol TCP

    real_server 192.168.31.139 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
    
     real_server 192.168.31.140 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
[root@master ~]# systemctl restart keepalived
[root@master ~]# systemctl enable keepalived

配置备keepalived

[root@slave ~]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
    router_id lb02
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 71
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 121212
    }
    virtual_ipaddress {
        192.168.31.150
    }
    notify_master "/scripts/notify.sh master"
    notify_master "/scripts/notify.sh master"
}


virtual_server 192.168.31.150 80 {
    delay_loop 6
    lb_algo rr
    lb_kind NAT
    persistence_timeout 50
    protocol TCP

    real_server 192.168.31.139 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
    
     real_server 192.168.31.140 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
[root@slave ~]# systemctl restart keepalived
[root@slave ~]# systemctl enable keepalived

测试验证

在这里插入图片描述

模拟主宕机

[root@master ~]# poweroff
[root@slave ~]# ip a
[root@czh ~]# 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:29:01:bd:5c brd ff:ff:ff:ff:ff:ff
    inet 192.168.31.150/24 brd 192.168.31.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.31.138/24 brd 192.168.31.255 scope global secondary noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe01:bd5c/64 scope link 
       valid_lft forever preferred_lft forever

在这里插入图片描述