Keepalive高可用 漂移

博文參考

http://lanlian.blog.51cto.com/6790106/1303195/
http://blog.csdn.net/tantexian/article/details/50056229
http://www.yulongjun.com/linux/20170904-01-keepalived-introduction/

Keepalived簡介

• core模塊：爲keepalived的核心組件，負責主進程的啓動、維護以及全局配置文件的加載和解析；

• check：負責健康檢查，包括常見的各類檢查方式；

• VRRP模塊：是來實現VRRP協議的。

keepalived

基於VRRP協議來實現的LVS服務高可用方案，能夠利用其來避免單點故障。一個LVS服務會有2臺服務器運行Keepalived，一臺爲主服務器（MASTER），一臺爲備份服務器（BACKUP），可是對外表現爲一個虛擬IP，主服務器會發送特定的消息給備份服務器，當備份服務器收不到這個消息的時候，即主服務器宕機的時候， 備份服務器就會接管虛擬IP，繼續提供服務，從而保證了高可用性。Keepalived是VRRP的完美實現。

啓動後三個進程

父進程：內存管理，子進程管理等等
子進程：VRRP子進程
子進程：healthchecker子進程

VRRP協議簡介

VRRP全稱Virtual Router Redundancy Protocol，即虛擬路由冗餘協議。
    虛擬路由冗餘協議，能夠認爲是實現路由器高可用的協議，即將N臺提供相同功能的路由器組成一個路由器組，這個組裏面有一個master和多個backup，master上面有一個對外提供服務的vip（該路由器所在局域網內其餘機器的默認路由爲該vip），master會發組播，當backup收不到vrrp包時就認爲master宕掉了，這時就須要根據VRRP的優先級來選舉一個backup當master。這樣的話就能夠保證路由器的高可用了。於安全性考慮，VRRP包使用了加密協議進行加密。

keepalived配置介紹

keepalived只有一個配置文件keepalived.conf，裏面主要包括如下幾個配置區域:

• global_defs主要是配置故障發生時的通知對象以及機器標識

• static_ipaddress和static_routes區域配置的是是本節點的IP和路由信息

• vrrp_script用來作健康檢查的，當時檢查失敗時會將vrrp_instancepriority減小相應的值

• vrrp_instance用來定義對外提供服務的VIP區域及其相關屬性

• vrrp_rsync_group用來定義vrrp_intance組，使得這個組內成員動做一致

全局配置

全局配置又包括兩個子配置：
全局定義(global definition)
靜態路由配置(static ipaddress/routes)

VRRPD配置

VRRPD配置包括三個類：
VRRP同步組(synchroization group)
VRRP實例(VRRP Instance)
VRRP腳本

keepalived單活雙活配置

單活配置

• Ka1配置

/etc/keepalived/keepalived.conf

global_defs {
   notification_email {
     root@localhost
   }
   notification_email_from ka1@localhost
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id ka1
   vrrp_mcast_group4 224.111.111.111
}
vrrp_instance VG_1 {
    state MASTER
    interface eth2
    virtual_router_id 191
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 0702f7ab
    }
    virtual_ipaddress {
        192.168.111.100
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"          
}

• Ka2配置

/etc/keepalived/keepalived.conf

global_defs {
   notification_email {
     root@localhost
   }
   notification_email_from ka1@localhost
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id ka1
   vrrp_mcast_group4 224.111.111.111
}
vrrp_instance VG_1 {
    state BACKUP
    interface eth2
    virtual_router_id 191
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 0702f7ab
    }
    virtual_ipaddress {
        192.168.111.100
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"          
}

雙活配置

• Ka1配置

/etc/keepalived/keepalived.conf

global_defs {
   notification_email {
     root@localhost
   }
   notification_email_from ka1@localhost
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id ka1
   vrrp_mcast_group4 224.111.111.111
}
vrrp_instance VG_1 {
    state MASTER
    interface eth2
    virtual_router_id 191
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 0702f7ab
    }
    virtual_ipaddress {
        192.168.111.100
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"          
}
vrrp_instance VG_2 {
    state BACKUP
    interface eth2
    virtual_router_id 192
    priority 95
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 85c9a27b
    }
    virtual_ipaddress {
        192.168.111.200
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"          
}

• Ka2配置

/etc/keepalived/keepalived.conf

global_defs {
   notification_email {
     root@localhost
   }
   notification_email_from ka1@localhost
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id ka1
   vrrp_mcast_group4 224.111.111.111
}
vrrp_instance VG_1 {
    state BACKUP
    interface eth2
    virtual_router_id 191
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 0702f7ab
    }
    virtual_ipaddress {
        192.168.111.100
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"  
}
vrrp_instance VG_2 {
    state MASTER
    interface eth2
    virtual_router_id 192
    priority 95
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 85c9a27b
    }
    virtual_ipaddress {
        192.168.111.200
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
}

內外雙網絡(非同步)單活模式漂移配置

一個內網網絡，一個外網網絡，內網網絡和外網網絡不用同步漂移，好比Keepalived+LVS-DR、Keepalived+Nginx、Keepalived+HAProxy，都是不用同步漂移的。（Keepalived+LVS-NAT是須要同步漂移的。）

• Ka1配置

/etc/keepalived/keepalived.conf

global_defs {
   notification_email {
     root@localhost
   }
   notification_email_from ka1@localhost
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id ka1
   vrrp_mcast_group4 224.111.111.111
}
vrrp_sync_group VG_1 {
    group {
        External_1
        Internal_1
    }
}
vrrp_instance External_1 {
    state MASTER
    interface eth1
    virtual_router_id 171
    priority 100
    advert_int 1    
    authentication {
        auth_type PASS
        auth_pass 1402b1b5
    }
    virtual_ipaddress {
        172.16.111.100
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
}
vrrp_instance Internal_1 {
    state MASTER
    interface eth2
    virtual_router_id 191
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 0702f7ab
    }
    virtual_ipaddress {
        192.168.111.100
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
}

• Ka2配置

/etc/keepalived/keepalived.conf

global_defs {
   notification_email {
     root@localhost
   }
   notification_email_from ka1@localhost
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id ka1
   vrrp_mcast_group4 224.111.111.111
}
vrrp_instance External_1 {
    state BACKUP
    interface eth1
    virtual_router_id 171
    priority 100
    advert_int 1    
    authentication {
        auth_type PASS
        auth_pass 1402b1b5
    }
    virtual_ipaddress {
        172.16.111.100
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
}
vrrp_instance Internal_1 {
    state BACKUP
    interface eth2
    virtual_router_id 191
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 0702f7ab
    }
    virtual_ipaddress {
        192.168.111.100
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
}

內外雙網絡(同步)雙活模式漂移配置

一個內網網絡，一個外網網絡，並且內網網絡和外網網絡要實現同步漂移，好比Keepalived+LVS-NAT模式，那麼就用到vrrp_sync_group來設置同步漂移組，若是要作雙活，那麼就分別兩端加兩個vip，互爲主備。

• Ka1配置

/etc/keepalived/keepalived.conf

global_defs {
   notification_email {
     root@localhost
   }
   notification_email_from ka1@localhost
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id ka1
   vrrp_mcast_group4 224.111.111.111
}
vrrp_sync_group VG_1 {
    group {
        External_1
        Internal_1
    }
}
vrrp_sync_group VG_2 {
    group {
        External_2
        Internal_2
    }
}
vrrp_instance External_1 {
    state MASTER
    interface eth1
    virtual_router_id 171
    priority 100
    advert_int 1    
    authentication {
        auth_type PASS
        auth_pass 1402b1b5
    }
    virtual_ipaddress {
        172.16.111.100
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
}
vrrp_instance External_2 {
    state BACKUP
    interface eth1
    virtual_router_id 172
    priority 95
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 9d3d15d5
    }
    virtual_ipaddress {
        172.16.111.200
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
}
vrrp_instance Internal_1 {
    state MASTER
    interface eth2
    virtual_router_id 191
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 0702f7ab
    }
    virtual_ipaddress {
        192.168.111.100
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
}
vrrp_instance Internal_2 {
    state BACKUP
    interface eth2
    virtual_router_id 192
    priority 95
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 85c9a27b
    }
    virtual_ipaddress {
        192.168.111.200
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
}

• Ka2配置

/etc/keepalived/keepalived.conf

global_defs {
   notification_email {
     root@localhost
   }
   notification_email_from ka1@localhost
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id ka1
   vrrp_mcast_group4 224.111.111.111
}
vrrp_sync_group VG_1 {
    group {
        External_1
        Internal_1
    }
}
vrrp_sync_group VG_2 {
    group {
        External_2
        Internal_2
    }
}
vrrp_instance External_1 {
    state BACKUP
    interface eth1
    virtual_router_id 171
    priority 100
    advert_int 1    
    authentication {
        auth_type PASS
        auth_pass 1402b1b5
    }
    virtual_ipaddress {
        172.16.111.100
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
}
vrrp_instance External_2 {
    state MASTER
    interface eth1
    virtual_router_id 172
    priority 95
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 9d3d15d5
    }
    virtual_ipaddress {
        172.16.111.200
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
}
vrrp_instance Internal_1 {
    state BACKUP
    interface eth2
    virtual_router_id 191
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 0702f7ab
    }
    virtual_ipaddress {
        192.168.111.100
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
}
vrrp_instance Internal_2 {
    state MASTER
    interface eth2
    virtual_router_id 192
    priority 95
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 85c9a27b
    }
    virtual_ipaddress {
        192.168.111.200
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
}