Keepalived+Nginx(主备模式) 高可用集群搭建演示

为什么要使用keepalived

Nginx作为反向代理服务器实现服务器分配资源负载均衡，但是如果有一天Nginx服务器宕机了，那用户的请求如何发送到服务器来呢?于是，keepalived作为检查服务器状态的软件来了！

主备模式搭建

整体架构图

172.16.10.185 模拟web服务器1
172.16.10.189 模拟web服务器2
172.16.10.186 keepalived + nginx 负载均衡服务器1
172.16.10.184 keepalived + nginx 负载均衡服务器2
172.16.10.190 模拟客户端测试

添加epel源：

curl -o /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo

四台机器关闭防火墙安装nginx:

systemctl stop firewalld         //关闭防火墙
sed -i 's/^SELINUX=.*/SELINUX=disabled/' /etc/sysconfig/selinux        //关闭selinux，重启生效
setenforce 0        　　　　　　　　//关闭selinux，临时生效
ntpdate 0.centos.pool.ntp.org    //时间同步
yum install nginx -y        　　　//安装nginx

两台模拟web修改

# vim /etc/nginx/nginx.conf        //编辑配置文件
user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;
include /usr/share/nginx/modules/*.conf;
events {
    worker_connections 1024;
}
http {
    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';
    access_log  /var/log/nginx/access.log  main;
    sendfile            on;
    tcp_nopush          on;
    tcp_nodelay         on;
    keepalive_timeout   65;
    types_hash_max_size 2048;
    include             /etc/nginx/mime.types;
    default_type        application/octet-stream;
    include /etc/nginx/conf.d/*.conf;
    server {
        listen       80;
        server_name  www.zhubing.com;
        location / {
            root         /usr/share/nginx/html;
        }
    access_log    /var/log/nginx/access.log main;
    }
}

两台LB服务器

# vim /etc/nginx/nginx.conf
user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;
include /usr/share/nginx/modules/*.conf;
events {
    worker_connections 1024;
}
http {
    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';
    access_log  /var/log/nginx/access.log  main;
    sendfile            on;
    tcp_nopush          on;
    tcp_nodelay         on;
    keepalive_timeout   65;
    types_hash_max_size 2048;
    include             /etc/nginx/mime.types;
    default_type        application/octet-stream;
    include /etc/nginx/conf.d/*.conf;
    upstream backend {
    server 172.16.10.185:80 weight=1 max_fails=3 fail_timeout=20s;
    server 172.16.10.189:80 weight=1 max_fails=3 fail_timeout=20s;
    }
    server {
        listen       80;
        server_name  www.mtian.org;
        location / {
        proxy_pass http://backend;
        proxy_set_header Host $host:$proxy_port;
        proxy_set_header X-Forwarded-For $remote_addr;
        }
    }
}

检测nginx配置文件语法是否正确

nginx -t

测试机器 配置域名解析
vim /etc/hosts

测试，看到均衡负载，证明nginx搭建成功

搭建keepalived,两台LB服务器

yum install -y keepalived

主：vim /etc/keepalived/keepalived.conf
注意 interface 属性 需要设置成自己的网卡名

从：vim /etc/keepalived/keepalived.conf

启动 keepalived
systemctl start keepalived
查看状态
systemctl status keepalived

我的查看状态发现dead状态

查看日志重启,需要开两个终端

tail -f /var/log/message 
systemctl restart keepalived 

发现interface 配置错了，
小插曲：如果发现启动不了，不要慌，tail -f /var/log/message 查看日志

启动之后 查看ip（主）

[root@k8s-slave2 nginx] ip a

我们在测试机上访问 vip

从机

因为从设置的是backup模式，所以不会出现vip，只有当主keepalived 挂掉，就会漂移到从机

systemctl stop keepalived.service

在从服务器中出现vip

访问vip依旧是通的

至此Keepalived+Nginx高可用主备模式搭建成功！