keepalived+nginx高可用

一，准备：

准备两节点：

master:192.168.122.21

backup:192.168.122.22

准备两个vip

vip1:192.168.122.16

vip2:192.168.122.17

关闭所有节点防火墙

关闭所有节点selinux

二，安装：

所有节点yum安装keepalived,nginx

keepalived,nginx设置开机自启

为了方便辨识，修改两节点nginx默认首页

三，配置

1，主备争抢模式配置

主节点配置：

! Configuration File for keepalived

global_defs {
   router_id master
   vrrp_skip_check_adv_addr
   !vrrp_strict
   vrrp_garp_interval 1
   vrrp_gna_interval 1
}


vrrp_instance VI_1 {
    state MASTER
    interface ens3
    virtual_router_id 51
    priority 100
    advert_int 1
    !nopreempt
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.122.16
    }
    unicast_src_ip 192.168.122.21
    unicast_peer {
        192.168.122.22
    }
}

virtual_server 192.168.122.16 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.122.21 80 {
        weight 1
    }

    real_server 192.168.122.22 80 {
        weight 1
    }
}

备节点配置：

! Configuration File for keepalived

global_defs {
   router_id backup
   vrrp_skip_check_adv_addr
   !vrrp_strict
   vrrp_garp_interval 1
   vrrp_gna_interval 1
}


vrrp_instance VI_1 {
    state BACKUP
    interface ens3
    virtual_router_id 51
    priority 90
    advert_int 1
    !nopreempt
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.122.16
    }
    unicast_src_ip 192.168.122.22
    unicast_peer {
        192.168.122.21
    }
}

virtual_server 192.168.122.16 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.122.21 80 {
        weight 1
    }

    real_server 192.168.122.22 80 {
        weight 1
    }
}

2，主备非争抢模式：

两节点state都设置为BACKUP

两节点都取消注释nopreempt

3，双主模式

主节点配置：

! Configuration File for keepalived

global_defs {
   router_id master
   vrrp_skip_check_adv_addr
   !vrrp_strict
}


vrrp_instance VI_1 {
    state MASTER
    interface ens3
    virtual_router_id 51
    priority 100
    advert_int 1
    !nopreempt
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.122.16
    }
    unicast_src_ip 192.168.122.21
    unicast_peer {
        192.168.122.22
    }
}

vrrp_instance VI_2 {
    state BACKUP
    interface ens3
    virtual_router_id 50
    priority 90
    advert_int 1
    !nopreempt
    authentication {
        auth_type PASS
        auth_pass 2222
    }
    virtual_ipaddress {
        192.168.122.17
    }
    unicast_src_ip 192.168.122.21
    unicast_peer {
        192.168.122.22
    }
}

virtual_server 192.168.122.16 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.122.21 80 {
        weight 1
    }

    real_server 192.168.122.22 80 {
        weight 1
    }
}

virtual_server 192.168.122.17 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.122.21 80 {
        weight 1
    }

    real_server 192.168.122.22 80 {
        weight 1
    }
}

备节点配置：

! Configuration File for keepalived

global_defs {
   router_id backup
   vrrp_skip_check_adv_addr
   !vrrp_strict
   vrrp_garp_interval 1
   vrrp_gna_interval 1
}


vrrp_instance VI_1 {
    state BACKUP
    interface ens3
    virtual_router_id 51
    priority 90
    advert_int 1
    !nopreempt
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.122.16
    }
    unicast_src_ip 192.168.122.22
    unicast_peer {
        192.168.122.21
    }
}

vrrp_instance VI_2 {
    state MASTER
    interface ens3
    virtual_router_id 50
    priority 100
    advert_int 1
    !nopreempt
    authentication {
        auth_type PASS
        auth_pass 2222
    }
    virtual_ipaddress {
        192.168.122.17
    }
    unicast_src_ip 192.168.122.22
    unicast_peer {
        192.168.122.21
    }
}

virtual_server 192.168.122.16 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.122.21 80 {
        weight 1
    }

    real_server 192.168.122.22 80 {
        weight 1
    }
}

virtual_server 192.168.122.17 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.122.21 80 {
        weight 1
    }

    real_server 192.168.122.22 80 {
        weight 1
    }
}

四，说明

1，主备非争抢模式：初始状态一致，都是backup，优先级高者为主节点，主节点挂掉，备节点接替作为主节点，主节点重新上线后作为备节点

2，主备争抢模式：初始状态不一致，主节点为master，备节点为backup，并且主节点优先级高于备节点，主节点挂掉，备节点接替作为主节点，主节点重新上线后会夺回主节点权限，成为主节点，备节点重新成为备节点

3，双主模式：有两个vip，都可以访问，两节点互为主备，一个节点挂掉，两个vip依然都可以访问