双主Keepalive与lvs实现自动监控主机状态并实时切换

双主Keepalive与lvs实现自动监控主机状态并实时切换

环境:

  • 202.106.0.17:as Client
  • 202.106.0.27: as router
  • 192.168.205.37: as lvs1
  • 192.168.205.47: as lvs2
  • 192.168.205.57: as websrv1
  • 192.168.205.67: as websrv2
  • 192.168.205.77: as websrv3
  • 192.168.205.87: as websrv4
    注:所有操作系统默认停用firewalld,iptable为空,关闭selinux

版本:

  • OS: centos 7 1810 with mini install
  • keepalived
  • httpd

目地:

使用keepalived 监控四台web服务器,两台为一组,各使用一个虚拟IP地址,lvs1为vip1的主vip2的从,lvs2为vip2的主,vip1的从,互相主备, 并使用lvs做为负载均衡,并能自动的发现服务down机并自动移除故障主机,从而实现无故障调度。

配置router

  1. 开启路由转发功能
    [root@router data]#ech 1 > /proc/sys/net/ipv4/ip_forward
  2. 增加一个10.1.1.1在router的eth1上, 由于我要到lvs1和lvs2服务器时必须有路由,由于是两个主机的虚拟Ip是很有可能飘移,所以当其中一台down时无法确定在哪台主机上,为了安全不加路由,直接用IP直连。
    [root@router data]#ip a a 10.1.1.1/24 dev eth0:1

    先配置四台real server

  3. 在app1的两台服务器192.168.205.57/67上运行如下脚本

    [root@websrv1 data]#cat lvs_dr_rs.sh 
    #!/bin/bash
    vip=10.1.1.100
    gateway=192.168.205.27
    mask='24'
    dev=lo:1
    rpm -q httpd &> /dev/null || yum -y install httpd &>/dev/null
    service httpd start &> /dev/null && echo "The httpd Server is Ready!"
    echo "this is `hostname`" > /var/www/html/index.html
    
    case $1 in
    start)
        echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore
        echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore
        echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce
        echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce
        ip a a $vip/$mask dev $dev #broadcast $vip up
        ip route add default via $gateway dev eth0
        #route add -host $vip dev $dev
        echo "The RS Server is Ready!"
        ;;
    stop)
        systemctl restart network
        echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore
        echo 0 > /proc/sys/net/ipv4/conf/lo/arp_ignore
        echo 0 > /proc/sys/net/ipv4/conf/all/arp_announce
        echo 0 > /proc/sys/net/ipv4/conf/lo/arp_announce
        echo "The RS Server is Canceled!"
        ;;
    *) 
        echo "Usage: $(basename $0) start|stop"
        exit 1
        ;;
    esac
  4. 在app2的两台服务器192.168.205.77/87上运行如下脚本

    [root@websrv3 data]#cat lvs_dr_rs.sh 
    #!/bin/bash
    vip=10.1.1.200
    gateway=192.168.205.27
    mask='24'
    dev=lo:1
    rpm -q httpd &> /dev/null || yum -y install httpd &>/dev/null
    service httpd start &> /dev/null && echo "The httpd Server is Ready!"
    echo "this is `hostname`" > /var/www/html/index.html
    
    case $1 in
    start)
        echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore
        echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore
        echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce
        echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce
        ip address add $vip/$mask dev $dev #broadcast $vip up
        ip route add default via $gateway dev eth0
        #route add -host $vip dev $dev
        echo "The RS Server is Ready!"
        ;;
    stop)
        systemctl restart network
        echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore
        echo 0 > /proc/sys/net/ipv4/conf/lo/arp_ignore
        echo 0 > /proc/sys/net/ipv4/conf/all/arp_announce
        echo 0 > /proc/sys/net/ipv4/conf/lo/arp_announce
        echo "The RS Server is Canceled!"
        ;;
    *) 
        echo "Usage: $(basename $0) start|stop"
        exit 1
        ;;
    esac

    在两台lvs上做同样的动(除特别说明)

  5. 安装httpd服务,将sorry server放在本地的两台主机中
    yum install httpd
    echo server is under maitenance > /var/www/html/index.html
  6. 一定要加默认路由到router,如果加正确可以工作,但sorry server不会正常
    ip route add default via 192.168.205.27 dev eth0
  7. 为了访问方便最好是将两个lvs服务器之间做ssh key验证,用下面的方法就不用在47上再做一次了,真接实现互认证
    ssh-keygen
    scp -r /root/.ssh 192.168.205.47:/root
  8. 最好将host文件加入两台主机名称解析
    vi /etc/hosts
    192.168.205.37 websrv1
    192.168.205.47 websrv2
    scp /etc/hosts 192.168.205.47:/etc
  9. 安装keepalive, 为了能看清如何加的lvs策略,我们把iplvadm也装上
    yum install keepalived ipvsadm
  10. 在lvs1上修改配置文件
    [root@lsv1 ~]#vi /etc/keepalived/keepalived.conf 
    ! Configuration File for keepalived
    global_defs {
       notification_email {
         root@localhost
       }
       notification_email_from keepalive@localhost
       smtp_server 127.0.0.1
       smtp_connect_timeout 30
       router_id LVS1
       vrrp_mcast_group4 224.0.0.100                                                                          
    }
    vrrp_instance VI_1 {
        state MASTER
        interface eth0
        virtual_router_id 37
        priority 100
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass centos
        }
        virtual_ipaddress {
            10.1.1.100/24 dev eth0 label eth0:0
        }
    }
    vrrp_instance VI_2 {
        state BACKUP
        interface eth0
        virtual_router_id 47
        priority 80
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass centos
        }
        virtual_ipaddress {
            10.1.1.200/24 dev eth0 label eth0:1
        }
    }
    virtual_server 10.1.1.100 80 {
        delay_loop 6
        lb_algo rr 
        lb_kind DR
        protocol TCP
        sorry_server 127.0.0.1 80
        real_server 192.168.205.57 80 {
            weight 1
            HTTP_GET {
                url { 
                  path /
                  status_code 200
                }
                connect_timeout 1
                nb_get_retry 3
                delay_before_retry 1
            }
        }
        real_server 192.168.205.67 80 {
            weight 1
            HTTP_GET {
                url { 
                  path /
                  status_code 200
                }
                connect_timeout 1
                nb_get_retry 3
                delay_before_retry 1
            }
        }                            
    }
    virtual_server 10.1.1.200 80 {
        delay_loop 6
        lb_algo rr 
        lb_kind DR
        protocol TCP
        sorry_server 127.0.0.1 80
        real_server 192.168.205.77 80 {
            weight 1
            HTTP_GET {
                url { 
                  path /
                  status_code 200
                }
                connect_timeout 1
                nb_get_retry 3
                delay_before_retry 1
            }
        }
        real_server 192.168.205.87 80 {
            weight 1
            HTTP_GET {
                url { 
                  path /
                  status_code 200
                }
                connect_timeout 1
                nb_get_retry 3
                delay_before_retry 1
            }
        }
    }            
    11. 为了方便将lsv1的keepalive.conf复制到lvs2上,并进行修改
    [root@lvs2 ~]#vi /etc/keepalived/keepalived.conf 
    ! Configuration File for keepalived
    global_defs {
       notification_email {
         root@localhost
       }
       notification_email_from keepalive@localhost
       smtp_server 127.0.0.1
       smtp_connect_timeout 30
       router_id LVS2
             vrrp_mcast_group4 224.0.0.100
    }
    vrrp_instance VI_1 {
        state BACKUP
        interface eth0
        virtual_router_id 37
        priority 80
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass centos
        }
        virtual_ipaddress {
            10.1.1.100/24 dev eth0 label eth0:0
        }
    }
    vrrp_instance VI_2 {
        state MASTER
        interface eth0
        virtual_router_id 47
        priority 100
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass centos
        }
        virtual_ipaddress {
            10.1.1.200/24 dev eth0 label eth0:1
        }
    }
    virtual_server 10.1.1.100 80 {
        delay_loop 6
        lb_algo rr 
        lb_kind DR
        protocol TCP
        sorry_server 127.0.0.1 80
        real_server 192.168.205.57 80 {
            weight 1
            HTTP_GET {
                url { 
                  path /
                  status_code 200
                }
                connect_timeout 1
                nb_get_retry 3
                delay_before_retry 1
            }
        }
        real_server 192.168.205.67 80 {
            weight 1
            HTTP_GET {
                url { 
                  path /
                  status_code 200
                }
                connect_timeout 1
                nb_get_retry 3
                delay_before_retry 1
            }
        }
    }
    virtual_server 10.1.1.200 80 {
        delay_loop 6
        lb_algo rr 
        lb_kind DR
        protocol TCP
        sorry_server 127.0.0.1 80
        real_server 192.168.205.77 80 {
            weight 1
            HTTP_GET {
                url { 
                  path /
                  status_code 200
                }
                connect_timeout 1
                nb_get_retry 3
                delay_before_retry 1
            }
        }
        real_server 192.168.205.87 80 {
            weight 1
            HTTP_GET {
                url { 
                  path /
                  status_code 200
                }
                connect_timeout 1
                nb_get_retry 3
                delay_before_retry 1
            }
        }
    }
  11. 起动keepalived服务
     systemctl start keepalived
  12. 在lvs1看到状态为RR调度
    [root@lsv1 ~]#ipvsadm -Ln
    IP Virtual Server version 1.2.1 (size=4096)
    Prot LocalAddress:Port Scheduler Flags
      -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
    TCP  10.1.1.100:80 rr
      -> 192.168.205.57:80            Route   1      0          0         
      -> 192.168.205.67:80            Route   1      0          0         
    TCP  10.1.1.200:80 rr
      -> 192.168.205.77:80            Route   1      0          0         
      -> 192.168.205.87:80            Route   1      0          0 
  13. 在lvs1中看到只一10.1.1.100IP, 在Lvs2中会看到只有10.1.1.200IP
    [root@lsv1 ~]#ip a
    2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
        link/ether 00:0c:29:56:e1:ea brd ff:ff:ff:ff:ff:ff
        inet 192.168.205.37/24 brd 192.168.205.255 scope global noprefixroute eth0
           valid_lft forever preferred_lft forever
        inet 10.1.1.100/24 scope global eth0:0
           valid_lft forever preferred_lft forever
        inet6 fe80::20c:29ff:fe56:e1ea/64 scope link noprefixroute 
           valid_lft forever preferred_lft forever
    [root@lvs2 ~]#ip a
    2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
        link/ether 00:0c:29:37:f9:93 brd ff:ff:ff:ff:ff:ff
        inet 192.168.205.47/24 brd 192.168.205.255 scope global noprefixroute eth0
           valid_lft forever preferred_lft forever
        inet 10.1.1.200/24 scope global eth0:1
           valid_lft forever preferred_lft forever
        inet6 fe80::20c:29ff:fe37:f993/64 scope link noprefixroute 
           valid_lft forever preferred_lft forever

    测试

  14. 在client上运行一个循环进行测试
    [root@client ~]#while : ;do curl 10.1.1.100; sleep 0.5; done
    this is websrv1
    this is websrv2
    this is websrv1
    this is websrv2
    this is websrv1
    this is websrv2
    [root@client ~]#while : ;do curl 10.1.1.200; sleep 0.5; done 
    this is websrv4
    this is websrv3
    this is websrv4
    this is websrv3
    this is websrv4
  15. 停掉web1,再测试,发现只会调度到web2
    [root@websrv1 data]#systemctl stop httpd
    [root@client ~]#while : ;do curl 10.1.1.100; sleep 0.5; done
    this is websrv2
    this is websrv2
    this is websrv2
    this is websrv2
    this is websrv2
  16. 停掉web2,再测试,发现sorry server带替工作,并在lvs1上可以看到127.0.0.1加载
    [root@websrv2 ~]#systemctl stop httpd
    [root@client ~]#while : ;do curl 10.1.1.100; sleep 0.5; done
    server is under maitenance
    server is under maitenance
    server is under maitenance
    server is under maitenance
    [root@lsv1 ~]#ipvsadm -Ln
    IP Virtual Server version 1.2.1 (size=4096)
    Prot LocalAddress:Port Scheduler Flags
      -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
    TCP  10.1.1.100:80 rr
      -> 127.0.0.1:80                 Route   1      0          4         
    TCP  10.1.1.200:80 rr
      -> 192.168.205.77:80            Route   1      0          0         
      -> 192.168.205.87:80            Route   1      0          0       
  17. 恢复两个websrv1 和websrv2,并停掉lvs2, 发现没有影响,但可以看到两个vip全部回到lvs1上
    [root@websrv1 ~]#systemctl start httpd
    [root@websrv2 ~]#systemctl start httpd
    [root@lvs2 ~]#systemctl stop keepalived
    [root@client ~]#while : ;do curl 10.1.1.100; sleep 0.5; done
    this is websrv2
    this is websrv1
    this is websrv2
    this is websrv1
    [root@client ~]#while : ;do curl 10.1.1.200; sleep 0.5; done
    this is websrv3
    this is websrv4
    this is websrv3
    this is websrv4
    [root@lsv1 ~]#ip a
    2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
        link/ether 00:0c:29:56:e1:ea brd ff:ff:ff:ff:ff:ff
        inet 192.168.205.37/24 brd 192.168.205.255 scope global noprefixroute eth0
           valid_lft forever preferred_lft forever
        inet 10.1.1.100/24 scope global eth0:0
           valid_lft forever preferred_lft forever
        inet 10.1.1.200/24 scope global secondary eth0:1
           valid_lft forever preferred_lft forever
        inet6 fe80::20c:29ff:fe56:e1ea/64 scope link noprefixroute 
           valid_lft forever preferred_lft forever
  18. 将lvs2恢复状态,因为有抢占功能又回到原来的主和备份上
    [root@client ~]#while : ;do curl 10.1.1.100; sleep 0.5; done
    this is websrv2
    this is websrv1
    this is websrv2
    [root@client ~]#while : ;do curl 10.1.1.200; sleep 0.5; done
    this is websrv4
    this is websrv3
    this is websrv4
    [root@lsv1 ~]#ip a
    2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
        link/ether 00:0c:29:56:e1:ea brd ff:ff:ff:ff:ff:ff
        inet 192.168.205.37/24 brd 192.168.205.255 scope global noprefixroute eth0
           valid_lft forever preferred_lft forever
        inet 10.1.1.100/24 scope global eth0:0
           valid_lft forever preferred_lft forever
        inet6 fe80::20c:29ff:fe56:e1ea/64 scope link noprefixroute 
           valid_lft forever preferred_lft forever
    [root@lvs2 ~]#ip a
    2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
        link/ether 00:0c:29:37:f9:93 brd ff:ff:ff:ff:ff:ff
        inet 192.168.205.47/24 brd 192.168.205.255 scope global noprefixroute eth0
           valid_lft forever preferred_lft forever
        inet 10.1.1.200/24 scope global eth0:1
           valid_lft forever preferred_lft forever
        inet6 fe80::20c:29ff:fe37:f993/64 scope link noprefixroute 
           valid_lft forever preferred_lft forever
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