Nginx+keepalived实现高可用集群 #yyds干货盘点#

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1.图解nginx七层与四层

大型企业架构一般是用户先访问到四层负载均衡，在由四层负载均衡转发至七层服务在均衡，七层负载均衡再转发至后端服务器，四层负载均衡只起到一个分流的作用，根据用户访问的端口，比如说80端口就会跳转至七层的对应的集群，两台四层负载均衡配置是一模一样的，形成高可用，七层的配置也是一模一样的，当有1500个请求需要响应时，四层负载均衡就会平均将1500个请求分给急群中的lb，每个lb响应500个请求，减轻单点的压力。

  • 负载均衡的选择

    • Nginx 四层和七层
    • LVS 四层，需要懂网络（NAT，iptables）
    • HAproxy 四层和七层
    • F5 四层和七层，硬件设备，不适合云平台
    • SLB 四层

  • session

    • 会话保持，可以采用ip_hash

    • 会话共享，最好写入 redis或者mysql

    • 写入浏览器，由开发人员实现

2.负载均衡手机端配置

upstream firefox 
    server 172.31.57.133:80;


upstream chrome 
    server 172.31.57.133:8080;


upstream iphone 
    server 172.31.57.134:8081;


upstream android 
    server172.31.57.134:8081；


upstream default 
    server 172.31.57.134:80；


server 
    if ($http_user_agent ~* "iphone")
        proxy_pass http://iphone;
    

    if ($http_user_agent ~* "chrome")
        proxy_pass http://chrome

进入高可用环节

3.高可用概念

3.1.什么是高可用

一般指2台机器启动着相同的业务系统，当有一台机器down机了，另外一台服务器能快速的接管，对于访问当用户是无感知的

3.2.高可用使用场景

业务系统需要保证7x24小时不down机，作为业务来说要随机都可以用，让你的业务系统更顽强。

4.Keepalive工作 原理

vrrp工作原理

1.将所有设备加入到一个虚拟组

2.具有相同的虚拟ip（会有对应的虚拟MAC地址）

3.主机会在发送数据的时候，在数据包的目标地址写上虚拟的IP及MAC

4.虚拟组收到数据后，会将目标地址转换成当前虚拟组的master设备的IP和MAC

vrrp角色：一主多备

实际工作角色：主

通过优先级来选举主备：优先级越高越优先

如果虚拟组中的服务器都认为自己是master这时就产生了裂脑

5.keepalived高可用安装部署

5.1.环境规划

服务器系统 角色 ip地址
centos7.5 keepalive-master ens33:192.168.81.210
centos7.5 keepalive-backup ens33:192.168.81.220

5.2.在两台机器上分别安装keepalive

1.配置yum仓库，下载镜像源
[root@localhost ~]# curl -o /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo 
[root@localhost ~]# curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

2.安装keepalive，将软件包下载至本地推送至其他服务器，方便机器安装
[root@localhost ~]# yum -y install keepalived --downloaddir=/root/soft
[root@localhost ~]# scp keepalived-1.3.5-16.el7.x86_64.rpm root@192.168.81.220:/root

3.第二台机器直接安装下载好的rpm包即可
[root@localhost ~]# yum localinstall /root/keepalived-1.3.5-16.el7.x86_64.rpm -y

5.3.配置keepalive-master

[root@localhost keepalived]# cp keepalived.conf keepalived.conf.bak
[root@localhost keepalived]# vim keepalived.conf
global_defs 
   router_id lb01           //路由名称，不能使用相同的路由名称


vrrp_instance VI_1         //定义一个虚拟组实例，实例名是VI_1，不建议修改
    state MASTER                //服务器的状态
    interface ens33             //提供服务的网卡名称即通信端口
    virtual_router_id 51            //实例的ID
    priority 150            //优先级，master要比backup的高，默认100，最高255
    advert_int 1            //心跳建哥，也就是健康检测周期，1表示1秒内与backup进行健康检查，检查失败立刻抢占
    authentication         
        auth_type PASS      //PASS认证类型，此参数备节点和主节点相同
        auth_pass 1111      //密码是1111，此参数备节点和主节点相同
           
    virtual_ipaddress          //定义一个漂移ip
       192.168.81.100

5.4.配置keepalive-backup

[root@localhost keepalived]# cp keepalived.conf keepalived.conf.bak
[root@localhost keepalived]# vim keepalived.conf
global_defs 
    router_id lb02


vrrp_instance VI_1 
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication 
        auth_type PASS
        auth_pass 1111
    
    virtual_ipaddress 
       192.168.81.100

5.5.启动主备服务器的keepalived

keepalived-master
[root@localhost keepalived]# systemctl start keepalived
[root@localhost keepalived]# systemctl enable keepalived

keepalived-backup
[root@localhost keepalived]# systemctl start keepalived
[root@localhost keepalived]# systemctl enable keepalived

6.检查虚拟IP是否漂移

虚拟IP漂移时会产生一个丢包现象，master或者slave将进行抢占


下面开始验证，具体思路：

​ 1.主节点查看是否存在虚拟ip

​ 2.主节点停掉keepalived进程

​ 3.观察丢包

​ 4.从节点验证是否存在虚拟ip

​ 5.主节点开启keepalived进程

​ 6.主节点查看是否抢占成功虚拟ip

在keepalive-master上操作

已经获得漂移ip
[root@jxl ~]# ip add show dev ens33
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:46:66:34 brd ff:ff:ff:ff:ff:ff
    inet 192.168.81.220/24 brd 192.168.81.255 scope global ens33
       valid_lft forever preferred_lft forever
    inet 192.168.81.100/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe46:6634/64 scope link 
       valid_lft forever preferred_lft forever

在keepalive-master上恢复master节点并验证是否存在漂移ip

[root@localhost ~]# systemctl start keepalived
[root@localhost ~]# ip add show dev ens33
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:55:83:b7 brd ff:ff:ff:ff:ff:ff
    inet 192.168.81.210/24 brd 192.168.81.255 scope global ens33
       valid_lft forever preferred_lft forever
    inet 192.168.81.100/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe55:83b7/64 scope link 
       valid_lft forever preferred_lft forever

在keepalive-backup上验证漂移ip是否已丢失

[root@jxl ~]# ip add show dev ens33
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:46:66:34 brd ff:ff:ff:ff:ff:ff
    inet 192.168.81.220/24 brd 192.168.81.255 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe46:6634/64 scope link 
       valid_lft forever preferred_lft forever

7.keepalived主备配置区别

master配置 backup配置 含义
router_id lb01 router_id lb02 路由名称
state MASTER state BACKUP 服务器状态
priority 150 priority 100 服务器优先级

8.keepalived高可用配置

8.1.环境规划

角色 部署内容 IP
keepalived-master keepalived主 192.168.81.210
keepalived-backup keepalived备 192.168.81.220
nginx-负载1 nginx负载均衡 192.168.81.210
nginx-负载2 nginx负载均衡 192.168.81.220
web01 nginx 192.168.81.230
web02 nginx 192.168.81.240

8.2.实现思路

1.先部署web节点，在web节点上部署LNMP平台，并部署网站源码包

2.部署nginx负载均衡，再第一台部署好后直接推送过去

3.部署keepalive主备

8.3.部署web节点

详细部署步骤请参考https://blog.csdn.net/weixin_44953658/article/details/105928687

8.4.部署nginx负载均衡

lb01配置
[root@localhost ~]# yum -y install nginx 
[root@localhost ~]# cd /etc/nginx/conf.d
[root@localhost ~]# vim lb_wecenter.conf
upstream lb_wecenter 
    server 192.168.81.230 weight=1 max_fails=3 fail_timeout=60;
    server 192.168.81.240 weight=1 max_fails=3 fail_timeout=60;


server 
    listen 80;
    server_name jxl.wecenter.com;
    client_max_body_size 200m;
    access_log /nginx_log/lb_jxl_wecenter_access.log main;

    location / 
        proxy_pass http://lb_wecenter;
        proxy_set_header HOST $http_host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_connect_timeout 30;
        proxy_send_timeout 60;
        proxy_read_timeout 60;
        proxy_buffering on;
        proxy_buffer_size 256k;
        proxy_buffers 4 256k;
    


lb02配置
[root@localhost ~]# yum -y install nginx
然后在lb01使用scp将配置文件推送到lb02上
[root@localhost ~]# scp -rp /etc/nginx/* root@192.168.81.220:/etc/nginx/

在两台机器上启动nginx
[root@localhost ~]# systemctl start nginx 
[root@localhost ~]# systemctl enable nginx

8.5.配置keepalived主备

8.5.1.在两台机器上分别安装keepalive

1.配置yum仓库，下载镜像源
[root@localhost ~]# curl -o /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo 
[root@localhost ~]# curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

2.安装keepalive，将软件包下载至本地推送至其他服务器，方便机器安装
[root@localhost ~]# yum -y install keepalived --downloaddir=/root/soft
[root@localhost ~]# scp keepalived-1.3.5-16.el7.x86_64.rpm root@192.168.81.220:/root

3.第二台机器直接安装下载好的rpm包即可
[root@localhost ~]# yum localinstall /root/keepalived-1.3.5-16.el7.x86_64.rpm -y

8.5.2.配置keepalive-master

[root@localhost keepalived]# cp keepalived.conf keepalived.conf.bak
[root@localhost keepalived]# vim keepalived.conf
global_defs 
   router_id lb01           //路由名称，不能使用相同的路由名称


vrrp_instance VI_1         //定义一个虚拟组实例，实例名是VI_1，不建议修改
    state MASTER                //服务器的状态
    interface ens33             //提供服务的网卡名称即通信端口
    virtual_router_id 51            //实例的ID
    priority 150            //优先级，master要比backup的高，默认100，最高255
    advert_int 1            //心跳建哥，也就是健康检测周期，1表示1秒内与backup进行健康检查，检查失败立刻抢占
    authentication         
        auth_type PASS      //PASS认证类型，此参数备节点和主节点相同
        auth_pass 1111      //密码是1111，此参数备节点和主节点相同
           
    virtual_ipaddress          //定义一个漂移ip
       192.168.81.100

8.5.3.配置keepalive-backup

[root@localhost keepalived]# cp keepalived.conf keepalived.conf.bak
[root@localhost keepalived]# vim keepalived.conf
global_defs 
    router_id lb02


vrrp_instance VI_1 
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication 
        auth_type PASS
        auth_pass 1111
    
    virtual_ipaddress 
       192.168.81.100

8.5.4.启动主备服务器的keepalived

keepalived-master
[root@localhost keepalived]# systemctl start keepalived
[root@localhost keepalived]# systemctl enable keepalived

keepalived-backup
[root@localhost keepalived]# systemctl start keepalived
[root@localhost keepalived]# systemctl enable keepalived

8.6.页面访问

8.7.抓包验证

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