Keepalive之nginx調度架構

單主模式Keepalive之Nginx 調度

實驗目的：

實現Nginx調度的高可用，當一臺Nginx調度器故障時，啟用備用的Nginx調度，在架構中，啟用了kepalive節點狀態通知腳本機制，當keepalive的狀態由MASTER變為BACKUP或由BACKUP變為MASTER時，以郵件通知用戶，通過在通知腳本文件中定義BACKUP狀態的節點啟用nginx服務，是為了防止因Nginx服務故障導致節點權重降低從而變為BACKUP狀態，為了避免此種現象，故在轉換為BACKUP狀態時需啟動一次Nginx服務。

實驗環境

keepalive-A 172.16.253.108
keepalive-B 172.16.253.105
Nginx-A     172.16.253.108
Nginx-B     172.16.253.105
LVS-RS1     172.16.250.127
LVS-RS2     172.16.253.193
VIP         172.16.253.150
client      172.16.253.177

web服務集群

為了更好的觀察實驗結果，故在此將RS1和RS2的web頁面內容設置不一致，以致可以更清晰的區分RS1服務端和RS2服務端

LVS-RS1

[root@LVS-RS1 ~]# systemctl restart chronyd  \\多臺服務器時間同步
[root@LVS-RS1 ~]# iptables -F
[root@LVS-RS1 ~]# setenforce 0
[root@LVS-RS1 ~]# yum -y install nginx
[root@LVS-RS1 ~]# vim /usr/share/nginx/html/index.html 
<h1> Web RS1 </h1>
[root@LVS-RS1 ~]# systemctl start nginx

LVS-RS2

[root@LVS-RS2 ~]# systemctl restart chronyd  \\多臺服務器時間同步
[root@LVS-RS2 ~]# iptables -F
[root@LVS-RS2 ~]# setenforce 0
[root@LVS-RS2 ~]# yum -y install nginx
[root@LVS-RS2 ~]# vim /usr/share/nginx/html/index.html
<h1> Web RS2 </h1>
[root@LVS-RS2 ~]# systemctl start nginx

nginx調度集群

nginx-A

[root@nginx-A ~]# yum -y install nginx
[root@nginx-A ~]# vim /usr/share/nginx/html/index.html 
</h1> sorry from keepalive-A </h1>
[root@nginx-A ~]# vim /etc/nginx/nginx.conf
http {
    upstream websrvs {
        server 172.16.250.127:80;
        server 172.16.253.193:80;
    }
}
server {
    listen       80 default_server;
    location / {
        proxy_pass http://websrvs;
    }
}
[root@nginx-A ~]# systemctl start nginx

nginx-B

[root@nginx-B ~]# yum -y install nginx
[root@nginx-B ~]# vim /usr/share/nginx/html/index.html 
</h1> sorry from keepalive-B </h1>
[root@nginx-B ~]# vim /etc/nginx/nginx.conf
http {
    upstream websrvs {
        server 172.16.250.127:80;
        server 172.16.253.193:80;
    }
}
server {
    listen       80 default_server;
    location / {
        proxy_pass http://websrvs;
    }
}
[root@nginx-B ~]# systemctl start nginx

keepalive集群

keepalive-A

[root@keepalive-A ~]# yum -y install keepalived
[root@keepalive-A ~]# vim /etc/keepalived/notify.sh  \\定義狀態檢測通知腳本，當節點變為BACKUP時，啟動nginx服務
#!/bin/bash 
    #
    contact='root@localhost'  \\通知的聯系者，即本地郵件服務器的通知郵件接受者

    notify() {
       local mailsubject="$(hostname) to be $1, vip floating" \\指定郵件標題
       local mailbody="$(date +'%F %T'): vrrp transition, $(hostname) changed to be $1"  \\指定郵件正文
       echo "$mailbody" | mail -s "$mailsubject" $contact  \\發送通知信息郵件到郵件接收者
    }

    case $1 in
        master)
           notify master
           ;;
        backup)
            notify backup
            systemctl start nginx
            ;;      
        fault)
            notify fault    
            ;;
        *)
            echo "Usage: $(basename $0) {master|backup|fault}"
            exit 1
            ;;
        esac
[root@keepaliveA ~]# vim /etc/keepalived/keepalived.conf
global_defs {
    notification_email {
        jevon@danran.com
    }
    notification_email_from ka_admin@danran.com
    smtp_server 127.0.0.1
    smtp_connect_timeout 30
    router_id keepaliveA
    vrrp_mcast_group4 224.103.5.5
}
vrrp_script chk_mant_down { \\定義檢測腳本
    script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0" \\檢測/etc/keepalived/down文件是否存在，若文件存在，則weight權重-10，若文件不存在，則每隔一秒檢測
    interval 1 \\每隔一秒檢測
    weight -10
    fall 2 \\檢測兩次故障則表示節點故障
    rise 1 \\檢測一次正常則表示節點正常
}
vrrp_script chk_nginx { \\檢測nginx服務是否運行腳本
    script "killall -0 nginx" \\-0為探測信號，當nginx進程存在時，返回值$?=0,當nginx進程不存在時，返回值$?為非零，則權重減10
    interval 2
    weight -10
    fall 2
    rise 2
}

vrrp_instance VI_A {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 95
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass qr8hQHuL
    }
    virtual_ipaddress {
    172.16.253.150/32
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
    }
    track_script { \\腳本調用
        chk_mant_down
        chk_nginx \\調用chk_nginx腳本
    }
}
[root@keepalive-A ~]# systemctl start keepalived
[root@keepalive-A ~]# systemctl status keepalived

keepalive-B

[root@keepalive-B ~]# yum -y install keepalived
[root@keepalive-A ~]# vim /etc/keepalived/notify.sh  \\定義狀態檢測通知腳本
#!/bin/bash 
    #
    contact='root@localhost'  \\通知的聯系者，即本地郵件服務器的通知郵件接受者

    notify() {
       local mailsubject="$(hostname) to be $1, vip floating" \\指定郵件標題
       local mailbody="$(date +'%F %T'): vrrp transition, $(hostname) changed to be $1"  \\指定郵件正文
       echo "$mailbody" | mail -s "$mailsubject" $contact  \\發送通知信息郵件到郵件接收者
    }

    case $1 in
        master)
           notify master
           ;;
        backup)
            notify backup
            systemctl start nginx
            ;;      
        fault)
            notify fault    
            ;;
        *)
            echo "Usage: $(basename $0) {master|backup|fault}"
            exit 1
            ;;
        esac
[root@keepalive-B ~]# vim /etc/keepalived/keepalived.conf
global_defs {
    notification_email {
        jevon@danran.com
    }
    notification_email_from ka_admin@danran.com
    smtp_server 127.0.0.1
    smtp_connect_timeout 30
    router_id keepaliveA
    vrrp_mcast_group4 224.103.5.5
} 
vrrp_script chk_mant_down { \\定義檢測腳本
    script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0" \\檢測/etc/keepalived/down文件是否存在，若文件存在，則weight權重-10，若文件不存在，則每隔一秒檢測
    interval 1 \\每隔一秒檢測
    weight -10
    fall 2 \\檢測兩次故障則表示節點故障
    rise 1 \\檢測一次正常則表示節點正常
}
vrrp_script chk_nginx { \\檢測nginx服務是否運行腳本
    script "killall -0 nginx" \\-0為探測信號，當nginx進程存在時，返回值$?=0,當nginx進程不存在時，返回值$?為非零，則權重減10
    interval 2
    weight -10
    fall 2
    rise 2
}

vrrp_instance VI_A {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 95
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass qr8hQHuL
    }
    virtual_ipaddress {
    172.16.253.150/32
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
    }
    
    track_script { \\腳本調用
        chk_mant_down
        chk_nginx \\調用chk_nginx腳本
    }
}
[root@keepalive-B ~]# systemctl start keepalived
[root@keepalive-A ~]# systemctl start keepalived

測試

訪問測試調度

[root@client ~]# for i in {1..10};do curl http://172.16.253.150;done
<h1> Web RS1 </h1>
<h1> Web RS2 </h1>
<h1> Web RS1 </h1>
<h1> Web RS2 </h1>
<h1> Web RS1 </h1>

測試檢測監控Nginx服務資源的外部腳本

[root@keepalive-A ~]# ip a l
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:75:dc:3c brd ff:ff:ff:ff:ff:ff
    inet 172.16.253.150/32 scope global ens33
        valid_lft forever preferred_lft forever

手動停止Nginx服務，keepalive-A變成了BACKUP節點

[root@keepalive-A ~]# systemctl stop nginx
[root@keepalive-A ~]# ip a l
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:75:dc:3c brd ff:ff:ff:ff:ff:ff

幾秒種后，Nginx服務再次自動啟動，則Keepalive-A再次成為MASTER節點

[root@keepalive-A ~]# ip a l
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:75:dc:3c brd ff:ff:ff:ff:ff:ff
    inet 172.16.253.150/32 scope global ens33
        valid_lft forever preferred_lft forever

當Nginx的80端口占用時，Nginx服務停止之后不會再次啟動，則keepalive-A變為BACKUP

[root@keepalive-A ~]# yum -y install httpd 
[root@keepalive-A ~]# systemctl stop nginx && systemctl start httpd \\停止nginx的同時啟動httpd
[root@keepalive-A ~]# ip a l
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:75:dc:3c brd ff:ff:ff:ff:ff:ff
[root@keepalive-A ~]# systemctl status keepalived.service 
Sep 05 21:21:14 cxjing.com Keepalived_vrrp[24153]: VRRP_Script(chk_nginx) failed

在HTTP進程停止之后，80端口被釋放，則keepalive-A上的Nginx也不會再次重啟

雙主模式的Nginx調度（一般不會做會話綁定）

雙主模式的目的是為了解決訪問路徑的單點故障，當一個web虛擬路由故障時，可使用另外一個web路徑訪問，最終是實現集群的高可用性

實驗環境

keepalive-A 172.16.253.108
keepalive-B 172.16.253.105
Nginx-A     172.16.253.108
Nginx-B     172.16.253.105
LVS-RS1     172.16.250.127
LVS-RS2     172.16.253.193
VI-A        172.16.253.150
VI-B        172.16.253.140
client      172.16.253.177

環境拓撲圖

實現過程

keepalive-A

[root@keepalive-A ~]# vim /etc/keepalived/notify.sh 
#!/bin/bash
#
contact='root@localhost'

notify() {
    local mailsubject="$(hostname) to be $1, vip floating"
    local mailbody="$(date +'%F %T'): vrrp transition, $(hostname) changed to be $1"
    echo "$mailbody" | mail -s "$mailsubject" $contact
}

case $1 in
master)
    notify master
    ;;
backup)
    notify backup
    systemctl start nginx
    ;;
fault)
    notify fault
    ;;
*)
    echo "Usage: $(basename $0) {master|backup|fault}"
    exit 1
    ;;
esac
[root@keepalive-A ~]# systemctl stop keepalived  
[root@keepalive-A ~]# vim /etc/keepalived/keepalived.conf
global_defs {
notification_email {
    jevon@danran.com
}
notification_email_from ka_admin@danran.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id keepaliveA
vrrp_mcast_group4 224.103.5.5
}
vrrp_script chk_mant_down {
    script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
    interval 1
    weight -10
    fall 2
    rise 1
}
vrrp_script chk_nginx {
    script "killall -0 nginx"
    interval 2
    weight -10
    fall 2
    rise 2
}
vrrp_instance VI_A {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass qr8hQHuL
    }
    virtual_ipaddress {
        172.16.253.150/32
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
    }
    track_script {
        chk_mant_down
        chk_nginx
    }
}
vrrp_instance VI_B {
    state BACKUP
    interface ens33
    virtual_router_id 52
    priority 95
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass qr8hQH99
    }
    virtual_ipaddress {
        172.16.253.140/32
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
    }
    track_script {
        chk_mant_down
        chk_nginx
    }
}
[root@keepalive-A ~]# systemctl start keepalived

keepalive-B

[root@keepalive-A ~]# vim /etc/keepalived/notify.sh 
#!/bin/bash
#
contact='root@localhost'

notify() {
    local mailsubject="$(hostname) to be $1, vip floating"
    local mailbody="$(date +'%F %T'): vrrp transition, $(hostname) changed to be $1"
    echo "$mailbody" | mail -s "$mailsubject" $contact
}

case $1 in
master)
    notify master
    ;;
backup)
    notify backup
    systemctl start nginx
    ;;
fault)
    notify fault
    ;;
*)
    echo "Usage: $(basename $0) {master|backup|fault}"
    exit 1
    ;;
esac
[root@keepalive-B ~]# systemctl stop keepalived  
[root@keepalive-B ~]# vim /etc/keepalived/keepalived.conf
global_defs {
notification_email {
    jevon@danran.com
}
notification_email_from ka_admin@danran.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id keepaliveA
vrrp_mcast_group4 224.103.5.5
}
vrrp_script chk_mant_down {
    script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
    interval 1
    weight -10
    fall 2
    rise 1
}
vrrp_script chk_nginx {
    script "killall -0 nginx"
    interval 2
    weight -10
    fall 2
    rise 2
}
vrrp_instance VI_A {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 95
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass qr8hQHuL
    }
    virtual_ipaddress {
        172.16.253.150/32
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
    }
    track_script {
        chk_mant_down
        chk_nginx
    }
}
vrrp_instance VI_B {
    state MASTER
    interface ens33
    virtual_router_id 52
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass qr8hQH99
    }
    virtual_ipaddress {
        172.16.253.140/32
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
    }
    track_script {
        chk_mant_down
        chk_nginx
    }
}
[root@keepalive-B ~]# systemctl start keepalived

查看keepalive-A和keepalive-B IP地址，確認虛擬路由配置正確

[root@keepalive-A ~]# ip a l
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:75:dc:3c brd ff:ff:ff:ff:ff:ff
    inet 172.16.253.150/32 scope global ens33
   valid_lft forever preferred_lft forever
[root@keepalive-B ~]# ip a l
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:0e:47:87 brd ff:ff:ff:ff:ff:ff
    inet 172.16.253.140/32 scope global ens33
   valid_lft forever preferred_lft forever

測試Nginx調度

[root@client ~]# for i in {1..10};do curl http://172.16.253.150;done
<h1> Web RS1 </h1>
<h1> Web RS2 </h1>
<h1> Web RS1 </h1>
<h1> Web RS2 </h1>
<h1> Web RS1 </h1>
[root@client ~]# for i in {1..10};do curl http://172.16.253.140;done
<h1> Web RS1 </h1>
<h1> Web RS2 </h1>
<h1> Web RS1 </h1>
<h1> Web RS2 </h1>
<h1> Web RS1 </h1>
<h1> Web RS2 </h1>
<h1> Web RS1 </h1>
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