lvs+keepalived+httpd高可用集羣

時間 2021-01-19

標籤 html web 算法 vim 後端 centos bash 服務器負載均衡 curl 欄目負載均衡简体版

原文原文鏈接

實驗環境

（1）本次基於VMware Workstation搭建一個四臺Linux（CentOS 7.4）系統所構成的一個服務器集羣，其中兩臺負載均衡服務器（一臺爲主機，另外一臺爲備機），另外兩臺做爲真實的Web服務器（向外部提供http服務，這裏僅僅使用了CentOS默認自帶的http服務，沒有安裝其餘的相似Tomcat、Jexus服務）。html

　　（2）本次實驗基於DR負載均衡模式，設置了一個VIP（Virtual IP）爲172.18.38.99，用戶只須要訪問這個IP地址便可得到網頁服務。其中，負載均衡主機爲172.18.38.100，備機爲172.18.38.101。Web服務器A爲172.18.38.200，Web服務器B爲172.18.38.201。web

實驗準備

(1)，綁定靜態IP地址

[root@centos7-100 ~]# nmcli connection modify ens37 ipv4.addresses 172.18.38.100/16 ipv4.method manual connection.autoconnect yes 
    [root@centos7-101 ~]# nmcli connection modify ens37 ipv4.addresses 172.18.38.101/16 ipv4.method manual connection.autoconnect yes 
    [root@centos7-200 ~]# nmcli connection modify ens37 ipv4.addresses 172.18.38.200/16 ipv4.method manual connection.autoconnect yes 
    [root@centos7-201 ~]# nmcli connection modify ens37 ipv4.addresses 172.18.38.201/16 ipv4.method manual connection.autoconnect yes

(2)，同步時間

利用chronyd服務同步時間算法

1，在四臺主機上都執行下面的命令，注意時間服務器必須是一臺vim

1，修改配置文件
     vim /etc/chrony.conf
        # Please consider joining the pool (http://www.pool.ntp.org/join.html).
        server 172.18.0.1  iburst #指定一臺服務器
    2，利用下面這條命令概略同步一下
      ntpdate 172.18.0.1 
     1 Apr 13:23:31 ntpdate[8517]: adjust time server 172.18.0.1 offset -0.350642 sec
    3，重啓chrony服務
     systemctl restart chronyd.service

(3)，關閉防火牆

systemctl disable firewalld
    systemctl stop firewalld

(3)，LVS+keepalived主從配置

1，在兩臺lvs服務器下載keepalived後端

yum  -y install keepalived

1，keepvlived_master+lvs配置文件centos

vim /etc/keepalived/keepalived.conf 

    ! Configuration File for keepalived

    global_defs {
       notification_email {
         root@localhost   #出問題了發郵件給誰
       }
       notification_email_from keepalived@localhost
       smtp_server 127.0.0.1 #本機郵件服務器
       smtp_connect_timeout 30 #超時時間
       router_id proxy1  #服務器id
       vrrp_mcast_group4 224.1.1.1 #多播地址全部的keepalived會在這個地址通信，決定誰工做
    }

    vrrp_instance VI_1 {
        state MASTER  #主服務器
        interface ens37 #網卡接口
        virtual_router_id 66 #服務器id
        priority 100  #優先級，
        advert_int 1 #心跳檢測 1秒一次
        authentication { #驗證
            auth_type PASS  #驗證類型，基於密碼
            auth_pass 123456 #密碼
        }
        virtual_ipaddress {
            172.18.38.99/16 #共享IP
        }

    }
    virtual_server 172.18.38.99 80 {
        delay_loop 6  
        lb_algo rr  #調度算法
        lb_kind DR  #調度模型
        #persistence_timeout 50 
        protocol TCP 
        sorry_server 127.0.0.1 80 
        real_server 172.18.38.200 80 {  #後端server_IP 及端口
            weight 1  #權重
            HTTP_GET {  #健康檢測方式
                url {
                  path /
                  status_code 200  
                }
                connect_timeout 3 #超時時間
                nb_get_retry 3 #重試次數
                delay_before_retry 3 #多長時間重試
            }
        }
        real_server 172.18.38.201 80 {
            weight 1
            HTTP_GET {
                url {
                  path /
                  status_code 200
                }
                connect_timeout 3
                nb_get_retry 3
                delay_before_retry 3
            }
        }
    }

2，keepalived_slave+lvs配置bash

vim /etc/keepalived/keepalived.conf

    ! Configuration File for keepalived

    global_defs {
       notification_email {
         root@localhost
       }
       notification_email_from keepalived@localhost
       smtp_server 127.0.0.1
       smtp_connect_timeout 30
       router_id proxy1
       vrrp_mcast_group4 224.1.1.1
    }

    vrrp_instance VI_2 {
        state SLAVE  "slave關鍵配置"
        interface ens37
        virtual_router_id 88
        priority 80
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass 123456
        }
        virtual_ipaddress {
            172.18.38.99/16
        }

    }
    virtual_server 172.18.38.99 80 {
        delay_loop 6
        lb_algo rr
        lb_kind DR
        #persistence_timeout 50
        protocol TCP
        sorry_server 127.0.0.1 80
        real_server 172.18.38.200 80 {
            weight 1
            HTTP_GET {
                url {
                  path /
                  status_code 200
                }
                connect_timeout 3
                nb_get_retry 3
                delay_before_retry 3
            }
        }
        real_server 172.18.38.201 80 {
            weight 1
            HTTP_GET {
                url {
                  path /
                  status_code 200
                }
                connect_timeout 3
                nb_get_retry 3
                delay_before_retry 3
            }
        }
    }

3，在兩臺lvs服務器下載ipvsadm包服務器

yum install ipvsadm

4，在兩臺lvs主機上都啓動keepalived服務負載均衡

systemctl start keepalived
    systemctl enable keepalived

5，注意這時候會在ens37網卡上加上一個新的IPcurl

[root@centos7-lvs_master ~]# ip a 
        ens37: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:50:56:39:48:cc brd ff:ff:ff:ff:ff:ff
    inet 172.18.38.101/16 brd 172.18.255.255 scope global ens37
       valid_lft forever preferred_lft forever
    inet 172.18.38.99/16 scope global secondary ens37
       valid_lft forever preferred_lft forever
    inet6 fe80::a7b9:b100:4f55:480e/64 scope link 
       valid_lft forever preferred_lft forever

[root@centos7-lvs_slave  ~]# ip a 
        ens37: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
            link/ether 00:50:56:39:48:cc brd ff:ff:ff:ff:ff:ff
            inet 172.18.38.101/16 brd 172.18.255.255 scope global ens37
                 valid_lft forever preferred_lft forever
            inet 172.18.38.99/16 scope global secondary ens37
                 valid_lft forever preferred_lft forever
            inet6 fe80::a7b9:b100:4f55:480e/64 scope link 
                 valid_lft forever preferred_lft forever

5，查看調度規則

[root@centos7-lvs_master ~]# ipvsadm -ln
    IP Virtual Server version 1.2.1 (size=4096)
    Prot LocalAddress:Port Scheduler Flags
      -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
    TCP  172.18.38.99:80 rr
      -> 172.18.38.200:80             Route   1      0          4         
      -> 172.18.38.201:80             Route   1      0          4    

    [root@centos7-lvs_slave  ~]# ipvsadm -ln
    IP Virtual Server version 1.2.1 (size=4096)
    Prot LocalAddress:Port Scheduler Flags
      -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
    TCP  172.18.38.99:80 rr
      -> 172.18.38.200:80             Route   1      0          0         
      -> 172.18.38.201:80             Route   1      0          0

(4)，配置2個後端web服務器

1，安裝httpd軟件

1，安裝httpd軟件
    yum install http
    2，啓動服務
        systemctl start httpd
        systemctl enable httpd
    2，生成web頁面，
        A主機
            echo web_server_A > /var/www/html/index.html
        b主機
            echo web_server_B > /var/www/html/index.html

2，在兩個web服務器執行下面的腳本，會在lo網卡上生成一個vip

vim lvs_br_rs.sh
    #!/bin/bash
    #Author:wangxiaochun
    #Date:2017-08-13
    vip=172.18.38.99   "只須要修改一下IP便可"
    mask='255.255.255.255'
    dev=lo:1

    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
        ifconfig $dev $vip netmask $mask #broadcast $vip up
        #route add -host $vip dev $dev
        echo "The RS Server is Ready!"
        ;;
    stop)
        ifconfig $dev down
        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

3，查看lo網卡

[root@centos7-web_server_A ~]# ip a 
    1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet 172.18.38.99/32 scope global lo:1
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever

    [root@centos7-web_server_B ~]# ip a 
    1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet 172.18.38.99/32 scope global lo:1
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever

客戶端測試

1，不宕任何服務

[root@centos6 ~]# for i in {1..10};do sleep 0.5;curl 172.18.38.99;done
    web_server_B
    web_server_A
    web_server_B
    web_server_A
    web_server_B
    web_server_A
    web_server_B
    web_server_A
    web_server_B
    web_server_A

2，宕掉一臺keepalived測試

[root@centos7 lvs_master ~]# systemctl stop keepalived.service

    [root@centos6 ~]# for i in {1..10};do sleep 0.5;curl 172.18.38.99;done
    web_server_B
    web_server_A
    web_server_B
    web_server_A
    web_server_B
    web_server_A
    web_server_B
    web_server_A
    web_server_B
    web_server_A

測試經過