[系统运维]高可用集群架构 Keepalived 双机主备和双主热备

一、资源准备：

二、Keepalived概念

1、解决单点故障

2 、组件免费

3、 可用实现高可用HA机制

4、 基于VRRP 协议

三、离线安装 Keepalived（三、四提供在线可选）

3.1 安装 keepalived(LB01,LB02 执行)

 （1）下载地址： https://www.keepalived.org/software/keepalived-2.0.18.tar.gz

 （2） 解压

tar -zxvf keepalived-2.0.18.tar.gz

（3）解压后进入到解压出来的目录，看到会有 configure ，那么就可用做配置了（配置安装和nginx一模一样）

（4）使用 configure 命令配置安装目录与核心配置文件所在位置

./configure --prefix=/usr/local/keepalived --sysconf=/etc

• prefix：keepalived安装的位置
• sysconf：keepalived核心配置文件所在位置，固定位置，改成其他位置keepalived启动不了，/var/log/messages中会报错
• a） 配置过程中可能会出现警告信息，如下所示
• *** WARNING - this build will not support IPVS with IPv6. Please install libnl/libnl-3 dev libraries to support IPv6 with IPVS.

yum -y install libnl libnl-devel  

• configure: error: no acceptable C compiler found in $PATH

sudo yum install gcc-c++ -y

• ./configure报错：OpenSSL is not properly installed on your system

 yum -y install openssl-devel

• 如果是没yum，则需要使用rpm来安装：

• rpm包可以在这个网站找，根据自己的系统选择： https://pkgs.org/download/openssl-devel

• b) 重新configure 一下，此时OK

./configure --prefix=/usr/local/keepalived --sysconf=/etc

(5) 安装keepalived

make && make install

(6) 进入到 /etc/keepalived,该目录下为keepalived核心配置文件

[root@lb-01 ~]# cd /etc/keepalived/

[root@lb-01 keepalived]# ll
-rw-r--r-- 1 root root 610 Mar  7 11:33 keepalived.conf

3.2 配置 Keepalived - 主

1、通过命令 vim /ect/keepalived/keepalived.conf 打开配置文件

global_defs {
   # 路由id：当前安装keepalived的节点主机标识符，保证全局唯一
   router_id NODEA
}

vrrp_instance VI_1 {
    state MASTER # 表示状态是MASTER主机还是备用机BACKUP
    interface ens33  # 该实例绑定的网卡
    virtual_router_id 51  #主、备必须一样 
    priority 100  # 权重，master权重一般高于backup，如果有多个，那就是选举，谁的权重高，谁就当选
    advert_int 2  # 主备之间同步检查时间间隔，单位秒
    authentication {
        auth_type PASS # 认证权限密码，防止非法节点进入
        auth_pass 1111
    }
    
    virtual_ipaddress {
        192.168.1.161  # 虚拟出来的ip，可以有多个（vip）
    }
}

附：查看网卡名称

ip addr

2、建立软链接

sudo ln -s /usr/local/keepalived/sbin/keepalived /sbin/
sudo ln -s /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/
sudo ln -s /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
sudo keepalived -D -f /usr/local/keepalived/etc/keepalived/keepalived.conf

3、启动

sudo keepalived -D -f /usr/local/keepalived/etc/keepalived/keepalived.conf

4、关闭

sudo killall keepalived

3.3 配置 Keepalived - 备

• 通过命令 vim /ect/keepalived/keepalived.conf 打开配置文件

global_defs {
   router_id NODEB
}

vrrp_instance VI_1 {
    # 备用机设置为BACKUP
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 80     # 权重低于MASTER
    advert_int 2
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.1.161  # 注意：主备两台的vip都是一样的，绑定到同一个vip
    }
}

3.4 主备对比图，左LB01为主，右LB02为备

四、在线安装 Keepalived （三、四可选）
安装Keepalived

yum -y install keepalived

配置Keepalived服务

vim /etc/keepalived/keepalived.con

启动停止

systemctl stop keepalived
systemctl start keepalived
systemctl enable keepalived

四、安装 NGINX

• 所有节点，进行如下安装：

//关闭并禁用防火墙
systemctl stop firewalld
systemctl disable firewalld

//关闭selinux
sed -i 's/^SELINUX=.*/SELINUX=disabled/' /etc/sysconfig/selinux
setenforce 0

//安装nginx
yum -y install nginx

//若提示，无安装包，则需要安装epel扩展源：
yum -y install epel-release

4.1 修改LB01 节点网站根目录默认文件

echo "<h1>LB01 121.40.33.77</h1>" > /usr/share/nginx/html/index.html

4.2 修改LB02 节点网站根目录默认文件

echo "<h1>LB02 120.26.223.87</h1>" > /usr/share/nginx/html/index.html

4.3 修改web01节点网站根目录默认文件

echo "<h1>web01 121.196.247.56</h1>" > /usr/share/nginx/html/index.html

4.4 修改web02节点网站根目录默认文件

echo "<h1>web02 120.55.242.145</h1>" > /usr/share/nginx/html/index.html

4.5 启动 nginx 服务(web01/web02)

systemctl start nginx
systemctl enable nginx

4.6 配置 LB01/LB02 服务器 nginx.conf

• 配置nginx反向代理服务，指向 web01、web02
  编辑nginx主配置文件：vi /etc/nginx/nginx.conf

    upstream server_pools {
       server 121.196.247.56:80;
       server 120.55.242.145:80;
    }
    server {
        listen       80;
        listen       [::]:80;
        server_name  www.test.com;
     #  root         /usr/share/nginx/html;

        # Load configuration files for the default server block.
        include /etc/nginx/default.d/*.conf;
        location / {
            proxy_pass http://server_pools;
        } 

4.7 配置 LB01/LB02 域名解析
Keepalived的虚拟VIP，与 nginx.conf 文件中 www.test.com 绑定

echo "192.168.1.161 www.test.com" >> /etc/hosts

4.8 启动 nginx（LB01/LB02）

systemctl start nginx
systemctl enable nginx

4.9 测试

• 打开 C:\Windows\System32\drivers\etc\hosts

• 末尾添加：192.168.1.161 www.test.com

• 注意：这里的IP指的是 keepalived 生成的虚拟VIP，即客户端通过VIP访问 web 业务浏览器，www.test.com域名指向LB01、LB02中server_name，并 upstream 到 web01、web02 业务浏览器
  

六、配置 Keepalived双主热备

规则：以一个虚拟ip分组归为同一路由

• 主节点 vim /ect/keepalived/keepalived.conf

global_defs {
   router_id keep_171
}

vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.1.161
    }
}

vrrp_instance VI_2 {
    state BACKUP
    interface ens33
    virtual_router_id 52
    priority 80
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.1.162
    }
}

• 备用节点 vim /ect/keepalived/keepalived.conf

global_defs {
   router_id keep_172
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 80
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.1.161
    }
}

vrrp_instance VI_2 {
    state MASTER
    interface ens33
    virtual_router_id 52
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.1.162
    }
}