Keepalived+Nginx實現高可用負載均衡集羣

時間  2019-11-11
標籤 keepalived+nginx keepalived nginx 實現 可用 負載 均衡 集羣 欄目 Nginx 简体版
原文   原文鏈接

一 環境介紹

1.操做系統
CentOS Linux release 7.2.1511 (Core)html

2.服務
keepalived+nginx雙主高可用負載均衡集羣及LAMP應用
keepalived-1.2.13-7.el7.x86_64
nginx-1.10.2-1.el7.x86_64
httpd-2.4.6-45.el7.centos.x86_64node


二 原理及拓撲圖

1.vrrp協議
在現實的網絡環境中，兩臺須要通訊的主機大多數狀況下並無直接的物理鏈接。對於這樣的狀況，它們之間路由怎樣選擇？主機如何選定到達目的主機的下一跳路由，這個問題一般的解決方法有二種：
 在主機上使用動態路由協議(RIP、OSPF等)
 在主機上配置靜態路由
很明顯，在主機上配置動態路由是很是不切實際的，由於管理、維護成本以及是否支持等諸多問題。配置靜態路由就變得十分流行，但路由器(或者說默認網關default gateway)卻常常成爲單點故障。VRRP的目的就是爲了解決靜態路由單點故障問題，VRRP經過一競選(election)協議來動態的將路由任務交給LAN中虛擬路由器中的某臺VRRP路由器。nginx

2.nginx反代
nginx是以反向代理的方式進行負載均衡的。反向代理（Reverse Proxy）方式是指以代理服務器來接受Internet上的鏈接請求，而後將請求轉發給內部網絡上的服務器，並將從服務器上獲得的結果返回給Internet上請求鏈接的客戶端，此時代理服務器對外就表現爲一個服務器。(爲了理解反向代理，這裏插播一條什麼是正向代理：正向代理指的是，一個位於客戶端和原始服務器之間的服務器，爲了從原始服務器取得內容，客戶端向代理髮送一個請求並指定目標(原始服務器)，而後代理向原始服務器轉交請求並將得到的內容返回給客戶端。)
3.拓撲圖web


三 配置

1.後端RS配置vim

[root@inode4 ~]# yum install httpd -y
[root@inode5 ~]# yum install httpd -y

 

 

2.Nginx反代配置
MASTER:後端

upstream websrvs {
 server 172.18.67.11:80;
 server 172.18.67.12:80;
 server 127.0.0.1:80 backup;
}
server {
    listen       80 ;
    location / {
    proxy_pass http://websrvs;
    }

 

BACKUP:centos

upstream websrvs {
 server 172.18.67.11:80;
 server 172.18.67.12:80;
 server 127.0.0.1:80 backup;
}
server {
    listen       80 ;
    location / {
    proxy_pass http://websrvs;
    }

 

3.keepalived高可用配置
MASTER:bash

! 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 node1
    vrrp_mcast_group4 224.0.67.67
}
vrrp_script chk_down {
    script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
    interval 1
    weight -5
}
vrrp_script chk_nginx {
    script "killall -0 nginx && exit 0 || exit 1"
    interval 1
    weight -5
    fall 2
    rise 1
}
vrrp_instance myr {
    state MASTER
    interface eno16777736
    virtual_router_id 167
    priority 100
    advert_int 1
    authentication {
 auth_type PASS
 auth_pass 571f97b2
    }
    virtual_ipaddress {
 172.18.67.33/16 dev eno16777736
    }
    track_script {
 chk_down
 chk_nginx
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
}

 

BACKUP:服務器

! 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 node1
    vrrp_mcast_group4 224.0.67.67
}
vrrp_script chk_down {
    script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
    interval 1
    weight -5
}
vrrp_script chk_nginx {
    script "killall -0 nginx && exit 0 || exit 1"
    interval 1
    weight -5
    fall 2
    rise 1
}
vrrp_instance myr {
    state BACKUP
    interface eno16777736
    virtual_router_id 167
    priority 95
    advert_int 1
    authentication {
 auth_type PASS
 auth_pass 571f97b2
    }
    virtual_ipaddress {
 172.18.67.33/16 dev eno16777736
    }
    track_script {
 chk_down
 chk_nginx
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
}

 

4.通知腳本示例網絡

[root@inode2 nginx]# vim notify.sh
#!/bin/bash
#
contact='root@localhost'
notify() {
 mailsubject="$(hostname) to be $1, vip floating"
 mailbody="$(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
 ;;
fault)
 notify fault
 ;;
*)
 echo "Usage: $(basename $0) {master|backup|fault}"
 exit 1
 ;;
esac


節點二一樣配置


四 啓動服務並測試

1.啓動後端web服務器

[root@inode4 ~]# systemctl start httpd
[root@inode5 ~]# systemctl start httpd


爲了測試顯示效果明顯一點，自定義一個訪問頁面

[root@inode4 ~]# echo "RS1:172.18.67.11" > /var/www/html/index.html
[root@inode5 ~]# echo "RS2:172.18.67.12" > /var/www/html/index.html

 

2.測試
MASTER:

[root@inode2 ~]# systemctl start  keepalived
[root@inode2 ~]# systemctl status -l  keepalived
● keepalived.service - LVS and VRRP High Availability Monitor
   Loaded: loaded (/usr/lib/systemd/system/keepalived.service; disabled; vendor preset: disabled)
   Active: active (running) since Mon 2017-05-15 15:45:20 CST; 3s ago
  Process: 20971 ExecStart=/usr/sbin/keepalived $KEEPALIVED_OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 20972 (keepalived)
   CGroup: /system.slice/keepalived.service
           ├─20972 /usr/sbin/keepalived -D
           ├─20973 /usr/sbin/keepalived -D
           └─20974 /usr/sbin/keepalived -D
May 15 15:45:20 inode2 Keepalived_healthcheckers[20973]: Opening file '/etc/keepalived/keepalived.conf'.
May 15 15:45:20 inode2 Keepalived_healthcheckers[20973]: Configuration is using : 7521 Bytes
May 15 15:45:20 inode2 Keepalived_healthcheckers[20973]: Using LinkWatch kernel netlink reflector...
May 15 15:45:20 inode2 Keepalived_vrrp[20974]: VRRP_Script(chk_nginx) succeeded
May 15 15:45:21 inode2 Keepalived_vrrp[20974]: VRRP_Instance(myr) Transition to MASTER STATE
May 15 15:45:22 inode2 Keepalived_vrrp[20974]: VRRP_Instance(myr) Entering MASTER STATE
May 15 15:45:22 inode2 Keepalived_vrrp[20974]: VRRP_Instance(myr) setting protocol VIPs.
May 15 15:45:22 inode2 Keepalived_vrrp[20974]: VRRP_Instance(myr) Sending gratuitous ARPs on eno16777736 for 172.18.67.33
May 15 15:45:22 inode2 Keepalived_vrrp[20974]: Opening script file /etc/keepalived/notify.sh
May 15 15:45:22 inode2 Keepalived_healthcheckers[20973]: Netlink reflector reports IP 172.18.67.33 added
[root@inode2 ~]# ip a l
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    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
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:8b:08:6f brd ff:ff:ff:ff:ff:ff
    inet 172.18.67.13/16 brd 172.18.255.255 scope global eno16777736
       valid_lft forever preferred_lft forever
    inet 172.18.67.33/16 scope global secondary eno16777736
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe8b:86f/64 scope link tentative dadfailed 
       valid_lft forever preferred_lft forever


主節點啓動，Entering MASTER STATE，此時咱們在客戶端進行測試訪問

[root@inode1 ~]# for i in {1..4};do curl http://172.18.67.33;done
RS1:172.18.67.11
RS2:172.18.67.12
RS1:172.18.67.11
RS2:172.18.67.12

 

訪問正常，接下來咱們啓動備用節點的服務器

BACKUP:

[root@inode3 keepalived]# systemctl start keepalived
[root@inode3 keepalived]# systemctl status -l keepalived
● keepalived.service - LVS and VRRP High Availability Monitor
   Loaded: loaded (/usr/lib/systemd/system/keepalived.service; disabled; vendor preset: disabled)
   Active: active (running) since Mon 2017-05-15 15:46:51 CST; 3s ago
  Process: 24329 ExecStart=/usr/sbin/keepalived $KEEPALIVED_OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 24330 (keepalived)
   CGroup: /system.slice/keepalived.service
           ├─24330 /usr/sbin/keepalived -D
           ├─24331 /usr/sbin/keepalived -D
           └─24332 /usr/sbin/keepalived -D
May 15 15:46:51 inode3 Keepalived_vrrp[24332]: Registering Kernel netlink command channel
May 15 15:46:51 inode3 Keepalived_vrrp[24332]: Registering gratuitous ARP shared channel
May 15 15:46:51 inode3 Keepalived_vrrp[24332]: Opening file '/etc/keepalived/keepalived.conf'.
May 15 15:46:51 inode3 Keepalived_vrrp[24332]: Configuration is using : 66427 Bytes
May 15 15:46:51 inode3 Keepalived_vrrp[24332]: Using LinkWatch kernel netlink reflector...
May 15 15:46:51 inode3 Keepalived_vrrp[24332]: VRRP_Instance(myr) Entering BACKUP STATE
May 15 15:46:51 inode3 Keepalived_vrrp[24332]: Opening script file /etc/keepalived/notify.sh
May 15 15:46:51 inode3 Keepalived_vrrp[24332]: VRRP sockpool: [ifindex(2), proto(112), unicast(0), fd(10,11)]
May 15 15:46:51 inode3 Keepalived_vrrp[24332]: VRRP_Script(chk_down) succeeded
May 15 15:46:51 inode3 Keepalived_vrrp[24332]: VRRP_Script(chk_nginx) succeeded
[root@inode3 keepalived]# ip a l
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    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
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:78:24:c3 brd ff:ff:ff:ff:ff:ff
    inet 172.18.67.14/16 brd 172.18.255.255 scope global eno16777736
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe78:24c3/64 scope link tentative dadfailed 
       valid_lft forever preferred_lft forever

 

此時，咱們能夠看到備用節點服務器啓動後進入了BACKUP狀態，Entering BACKUP STATE。接下來咱們測試主節點宕機的情形下，咱們的服務是否還可用

[root@inode2 ~]# systemctl stop keepalived


主節點宕機後咱們查看備用節點的狀態

[root@inode3 keepalived]# systemctl status -l keepalived
● keepalived.service - LVS and VRRP High Availability Monitor
   Loaded: loaded (/usr/lib/systemd/system/keepalived.service; disabled; vendor preset: disabled)
   Active: active (running) since Mon 2017-05-15 15:46:51 CST; 2min 19s ago
  Process: 24329 ExecStart=/usr/sbin/keepalived $KEEPALIVED_OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 24330 (keepalived)
   CGroup: /system.slice/keepalived.service
           ├─24330 /usr/sbin/keepalived -D
           ├─24331 /usr/sbin/keepalived -D
           └─24332 /usr/sbin/keepalived -D
May 15 15:46:51 inode3 Keepalived_vrrp[24332]: VRRP sockpool: [ifindex(2), proto(112), unicast(0), fd(10,11)]
May 15 15:46:51 inode3 Keepalived_vrrp[24332]: VRRP_Script(chk_down) succeeded
May 15 15:46:51 inode3 Keepalived_vrrp[24332]: VRRP_Script(chk_nginx) succeeded
May 15 15:48:35 inode3 Keepalived_vrrp[24332]: VRRP_Instance(myr) Transition to MASTER STATE
May 15 15:48:36 inode3 Keepalived_vrrp[24332]: VRRP_Instance(myr) Entering MASTER STATE
May 15 15:48:36 inode3 Keepalived_vrrp[24332]: VRRP_Instance(myr) setting protocol VIPs.
May 15 15:48:36 inode3 Keepalived_vrrp[24332]: VRRP_Instance(myr) Sending gratuitous ARPs on eno16777736 for 172.18.67.33
May 15 15:48:36 inode3 Keepalived_vrrp[24332]: Opening script file /etc/keepalived/notify.sh
May 15 15:48:36 inode3 Keepalived_healthcheckers[24331]: Netlink reflector reports IP 172.18.67.33 added
May 15 15:48:41 inode3 Keepalived_vrrp[24332]: VRRP_Instance(myr) Sending gratuitous ARPs on eno16777736 for 172.18.67.33
[root@inode3 keepalived]# ip a l
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 
    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
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:78:24:c3 brd ff:ff:ff:ff:ff:ff
    inet 172.18.67.14/16 brd 172.18.255.255 scope global eno16777736
       valid_lft forever preferred_lft forever
    inet 172.18.67.33/16 scope global secondary eno16777736
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe78:24c3/64 scope link tentative dadfailed 
       valid_lft forever preferred_lft forever

 

咱們發現備用節點由備用狀態進入了主狀態，而且IP地址也成功綁定至備用節點下。再次進行測試訪問

[root@inode1 ~]# for i in {1..4};do curl http://172.18.67.33;done
RS1:172.18.67.11
RS2:172.18.67.12
RS1:172.18.67.11
RS2:172.18.67.12

測試一臺web服務器宕機

[root@inode4 ~]# systemctl stop httpd
[root@inode1 ~]# for i in {1..4};do curl http://172.18.67.33;done
RS2:172.18.67.12
RS2:172.18.67.12
RS2:172.18.67.12
RS2:172.18.67.12

在實際生產環境中後端兩臺web服務器的內容應該同樣的，在這裏咱們可認爲客戶端已成功訪問到服務器，所以咱們可認爲這樣的架構體現了高可用負載均衡。

相關文章
相關標籤/搜索
每日一句
    每一个你不满意的现在，都有一个你没有努力的曾经。
本站公眾號
   歡迎關注本站公眾號,獲取更多信息
聯繫我們 最近搜索 最新文章 沪ICP备13005482号-10 MyBatis教程 SQL 教程 MySQL教程 Java 教程 Thymeleaf 教程 Hibernate教程 Spring教程 Redis教程