理论篇-负载均衡技术

2017-09-30

所有的高可用解决方案都是成本/复杂度与运行时间之间的权衡。

负载均衡技术有如下几个用途:

系统高可用
系统可扩展
负载均衡能力

要实现故障转移需要两个工具: ipvsadm和keepalived。(heartbeat也可实现类似功能，但配置相对复杂)

lvs核心ipvs

IPVS(IP Virtual Server)是故障转移的基础。IPVS供能由ipvsadm程序提供。

安装软件

1 2	yum install ipvsadm yum install keepalived

配置

master配置

! Configuration File for keepalived
global_defs {
    notification_email {
        xxx@xxx.com
    }
    !smtp_server 127.0.0.1
    !smtp_connect_timeout 30
    router_id PROXY_LVS_GIT_TEST_M
}
vrrp_instance VI_1 {
    state MASTER
    interface eth2
    virtual_router_id 100
    priority 100
    advert_int 5
    !smtp_alert  ! send an alert when this instance changes state from MASTER to BACKUP
    unicast_src_ip master_interface_ip  # 单播方式
    unicast_peer {
        slave_interface_ip_1
        slave_interface_ip_2
    }
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        10.153.227.43/22
    }
}

slave配置

! Configuration File for keepalived
global_defs {
    notification_email {
        xxx@xxx.com
    }
    !smtp_server 127.0.0.1
    !smtp_connect_timeout 30
    router_id PROXY_LVS_GIT_TEST_S
}
vrrp_instance VI_1 {
    state BACKUP
    interface eth2
    virtual_router_id 100
    priority 50
    advert_int 5
    !smtp_alert  ! send an alert when this instance changes state from MASTER to BACKUP
    nopreempt             # 当master恢复时，自动回到BACKUP状态
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        10.153.227.43/22
    }
}

启动与停止

1 2	service keepalived start service keepalived stop