LVS+KeepAlived+Nginx高可用软负载方案

范一刀

发布于 2021-08-10 11:36:06

2.4K0

发布于 2021-08-10 11:36:06

LVS是Linux Virtual Server的简称，也就是Linux虚拟服务器。通过LVS达到的负载均衡技术和Linux操作系统实现一个高性能高可用的Linux服务器群集，它具有良好的可靠性，可拓展性和可操作性。从而以低廉的成本实现负载均衡。 Keepalived的作用是检测服务器的状态，如果有一台web服务器宕机，或工作出现故障，Keepalived将检测到，并将有故障的服务器从系统中剔除，同时使用其他服务器代替该服务器的工作，当服务器工作正常后Keepalived自动将服务器加入到服务器群中，这些工作全部自动完成，不需要人工干涉，需要人工做的只是修复故障的服务器。

1. 环境说明

    192.168.100.113: keepalived-master
    192.168.100.114: keepalived-backup
    192.168.100.202: VIP
    192.168.100.117: nginx-1
    192.168.100.118: nginx-2

2. 拓扑图

keepalived实现虚拟IP（VIP），client访问VIP，连接到keepalived-master,keepliaved-master服务器通过LVS轮询机制将请求负载到nginx-1和nginx-2。

3. 部署nginx

安装ngixn安装ngixn

在192.168.100.117和192.168.100.118部署nginx

yum install gcc gcc-c++ pcre-devel openssl-devel -y
cd /opt
wget http://nginx.org/download/nginx-1.18.0.tar.gz 
tar -zxvf nginx-1.18.0.tar.gz
cd nginx-1.18.0 && \
./configure --prefix=/opt/nginx --with-http_stub_status_module --with-http_ssl_module  --with-http_realip_module --with-stream
make && make install

修改nginx默认首页内容修改nginx默认首页内容

vim /opt/nginx/html/index.html

192.168.100.117服务器： 将 Welcome to nginx! 改为 Welcome to nginx!--117 192.168.100.118服务器： 将 Welcome to nginx! 改为 Welcome to nginx!--118

启动两台nginx服务

/opt/nginx/sbin/nginx

访问nginx首页 http://192.168.100.117 http://192.168.100.118 浏览器可返回 Welcome to nginx!–117 Welcome to nginx!–118 的页面则nginx配置完成

4. lo网卡配置脚本

此环境配置LVS DR 模式，需要在后端nginx服务器lo网卡配置LVS的VIP vim /etc/init.d/realserver

#虚拟的vip 改为自己环境的vip
SNS_VIP=192.168.100.202
/etc/rc.d/init.d/functions
case "$1" in
start)
       ifconfig lo:0 $SNS_VIP netmask 255.255.255.255 broadcast $SNS_VIP
       /sbin/route add -host $SNS_VIP dev lo:0
       echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignore
       echo "2" >/proc/sys/net/ipv4/conf/lo/arp_announce
       echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore
       echo "2" >/proc/sys/net/ipv4/conf/all/arp_announce
       sysctl -p >/dev/null 2>&1
       echo "RealServer Start OK"
       ;;
stop)
       ifconfig lo:0 down
       route del $SNS_VIP >/dev/null 2>&1
       echo "0" >/proc/sys/net/ipv4/conf/lo/arp_ignore
       echo "0" >/proc/sys/net/ipv4/conf/lo/arp_announce
       echo "0" >/proc/sys/net/ipv4/conf/all/arp_ignore
       echo "0" >/proc/sys/net/ipv4/conf/all/arp_announce
       echo "RealServer Stoped"
       ;;
*)
       echo "Usage: $0 {start|stop}"
       exit 1
esac
exit 0

chmod 755 /etc/init.d/realserver
chmod 755 /etc/rc.d/init.d/functions
service realserver start

4. 部署keepalived

在192.168.100.113和192.168.100.114部署keepalived

安装依赖

yum install -y gcc openssl-devel  libnl libnl-devel  libnfnetlink-devel  wget

下载并安装keepalived

su - root 
cd ~
wget https://www.keepalived.org/software/keepalived-2.0.10.tar.gz
tar -zxvf keepalived-2.0.10.tar.gz
mv keepalived-2.0.10 /usr/local/keepalived
cd /usr/local/keepalived
./configure
make && make install
mkdir /etc/keepalived
cp /usr/local/keepalived/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
cp /usr/local/keepalived/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
cp /usr/local/sbin/keepalived /usr/sbin/

加入开机启动

cp /usr/local/keepalived/keepalived/etc/init.d/keepalived /etc/rc.d/init.d/

{hide}

配置keepalived

vim /etc/keepalived/keepalived.conf

192.168.100.113配置：

! Configuration File for keepalived

global_defs {
   router_id NG # 设置lvs的id，在一个网络内应该是唯一的
}

vrrp_instance VI_1 {
    state MASTER #指定Keepalived的角色，MASTER为主，BACKUP为备 一定大写
    interface eth0 #服务器网卡名
    virtual_router_id 51  #虚拟路由编号，主备要一致
    priority 100 #定义优先级，数字越大，优先级越高，主必须大于备
    advert_int 1 #检查间隔，默认为1s
    authentication { #这里配置的密码最多为8位，主备要一致，否则无法正常通讯
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.100.202 #定义虚拟IP(VIP)为192.168.100.202，可多设，每行一个
    }
}

virtual_server 192.168.100.202 80 {
    delay_loop 6 # 设置健康检查时间，单位是秒
    lb_algo rr #rr代表正常轮询模式，正式环境建议使用wlc加权最小连接数轮询
    lb_kind DR #DR模式：返回请求时，不走LVS，直接返回到客户端。
    nat_mask 255.255.255.0
    persistence_timeout 0
    protocol TCP

    real_server 192.168.100.117 80 { #后端服务器地址
        weight 1  # 配置节点权值，数字越大权重越高
        TCP_CHECK {
        connect_timeout 10
        nb_get_retry 3
        delay_before_retry 3
        connect_port 80
        }
    }
    real_server 192.168.100.118 80 {
        weight 1
        TCP_CHECK {
        connect_timeout 10
        nb_get_retry 3
        delay_before_retry 3
        connect_port 80
        }
    }
}

192.168.100.114配置：

! Configuration File for keepalived

global_defs {
   router_id NG
}

vrrp_instance VI_1 {
    state BACKUP  #此处改为BACKUP,一定要大写**
    interface eth0
    virtual_router_id 51
    priority 90  #此处改为90，要比master小**
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.100.202
    }
}

virtual_server 192.168.100.202 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    nat_mask 255.255.255.0
    persistence_timeout 50
    protocol TCP

    real_server 192.168.100.117 80 {
        weight 1
        TCP_CHECK {
        connect_timeout 10
        nb_get_retry 3
        delay_before_retry 3
        connect_port 80
        }
    }
    real_server 192.168.100.118 80 {
        weight 1
        TCP_CHECK {
        connect_timeout 10
        nb_get_retry 3
        delay_before_retry 3
        connect_port 80
        }
    }
}

keepalived

/etc/init.d/keepalived start
/etc/init.d/keepalived restart
/etc/init.d/keepalived stop

5. 测试LVS负载

VIP 将会自动配置到在192.168.100.113上，如果192.168.100.113宕机，VIP会漂移到192.168.100.114。浏览器访问VIP： http://192.168.100.202 会交替返回 Welcome to nginx!–117 Welcome to nginx!–118 两个页面，则LVS负载均衡配置成功。