基于Keepalived+Nginx实现高可用负载均衡

基础环境

• 操作系统：RHEL7.4(VM workstation 14pro)
• 数据库：mariadb10.1.28-systemd
• web服务器：Nginx1.10+php-fpm
• 文件服务器：NFS

DS服务器实现高可用

1、关闭selinux及防火墙

[root@localhost ~]#sed -i 's/SELINUX=enforcing/SELINUX=disabled' /etc/selinux/conf
[root@localhost ~]#systemctl stop firewalld
[root@localhost ~]#systemctl disable firewalld

2、配置Centos的yum源

配置如下：

[root@localhost ~]#cat /etc/yum.repo.d/Centos7.repo
[Centos7]
name=Centos7repo
baseurl=http://mirrors.aliyun.com/centos/7/os/x86_64/
gpgkey=http://mirror.aliyun.org/centos/7/os/x86_64/RPM-GPG-KEY-CentOS-7
gpgcheck=1
enable=1

3、安装并配置keepalived

[root@localhost ~]#yum install -y keepalived
[root@localhost ~]#cp /etc/keepalived/keepalived.conf{,.bak}
[root@localhost ~]#vim /etc/keealived/keepalived.conf
	! Configuration File for keepalived
	global_defs {
	#   notification_email {		告警通知的email
	#     [email protected]
	#     [email protected]
	#     [email protected]
	#   }
	#   notification_email_from [email protected]
	#   smtp_server 192.168.200.1
	#   smtp_connect_timeout 30
	   router_id LVS_DEVEL
	#   vrrp_skip_check_adv_addr
	#   vrrp_strict			默认开启情况下，当keepalived启动后，会在INPUT链上添加一条全DROP规则
	   vrrp_garp_interval 0
	   vrrp_gna_interval 0
	}
	vrrp_instance VI_1 {	实例名
	    state MASTER		主
	    interface ens33		实例指定网络接口
	    virtual_router_id 51		虚拟路由ID，主备相同
	    priority 100		主备优先级
	    advert_int 1
	    authentication {
	        auth_type PASS	认证方式
		auth_pass 1111		明文密码
	    }
	    virtual_ipaddress {
	        192.168.101.200	虚拟路由IP地址
	    }
	}

备机上需要对优先级，主备状态进行修改
	state BACKUP		备
	priority 80		主备优先级，值越大，级别越高
[root@localhost ~]#systemctl restart keepalived.service
可通过ping 192.168.101.200进行简单的测试

Mariadb、NFS服务器搭建

1、关闭selinux及防火墙

[root@localhost ~]#sed -i 's/SELINUX=enforcing/SELINUX=disabled' /etc/selinux/conf
[root@localhost ~]#systemctl stop firewalld
[root@localhost ~]#systemctl disable firewalld

2、创建用户、组

[root@localhost ~]#groupadd -g 700 mysql
[root@localhost ~]#useradd -u 700 -g mysql -s /sbin/nologin mysql
[root@localhost ~]#

3、安装mariadb数据库

因为systemd模式已经完全取代init，所以，在RHEL安装中最好使用systemd[Maridb安装包for systems with systemd](https://downloads.mariadb.org/mariadb/mariadb-10.1.28-linux-systemd-x86_64.tar.gz (for systems with systemd))
[root@localhost ~]#cd /tmp
[root@localhost tmp]#tar -zvxf mariadb-10.1.28-linux-systemd-x86_64.tar.gz
[root@localhost ~]#ln -s /tmp/mariadb-10.1.28 /usr/local/mysql		
[root@localhost ~]#cp /usr/local/mysql/support-files/mariadb.service /usr/lib/systemd/system/		复制mariadb.service文件至systemd加载目录
[root@localhost ~]#systemctl enable mariadb.service
[root@localhost ~]#cp /usr/local/mysql/my-large.cnf /etc/my.cnf		复制配置文件至/etc目录
[root@localhost ~]#sed -i '$aexport PATH=/usr/local/mysql/bin:$PATH' /etc/profile
[root@localhost ~]#source /etc/profile	添加环境变量
[root@localhost ~]#./usr/local/mysql/scripts/mysql_install_db --user=mysql
[root@localhost ~]#mysqladm -uroot passwod	指定root用户登录密码
[root@localhost ~]#systemctl start mariadb.service
[root@localhost ~]#mysql -uroot -p
Enter password:
	Welcome to the MariaDB monitor.  Commands end with ; or \g.
	Your MariaDB connection id is 6
	Server version: 10.1.28-MariaDB MariaDB Server
	Copyright (c) 2000, 2017, Oracle, MariaDB Corporation Ab and others.
	Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
	MariaDB [(none)]> 
	MariaDB [(none)]> grant all privileges on *.* to 'root'@'%' identified by '********';
	赋权root用户可以在任何主机通过******（密码） 访问所有数据库及表
	MariaDB [(none)]> flush privileges;

4、搭建NFS文件共享

[root@localhost ~]#yum install -y nfs-utils
[root@localhost ~]#mkdir /www
[root@localhost ~]#chown -R root:root /www
[root@localhost ~]#chmod -R 775 /www
[root@localhost ~]#vim /etc/exports
添加如下内容：
/www	192.168.101.0/24（rw，no_root_squash）
no_root_squash：root用户可以对该目录进行读写操作；
[root@localhost ~]#systemctl restart nfs.service
[root@localhost ~]#showmount -e
Export list for localhost.localdomain:
/www 192.168.101.0/24

RS（Nginx）服务器搭建

1、编译安装Nginx1.10

通过Nginx官方下载[Nginx1.10.tar.gz](http://nginx.org/download/nginx-1.10.3.tar.gz)
[root@localhost ~]#yum install -y gcc openssl-devel perl-devel pcre-devel perl-ExtUtils-Embed
[root@localhost ~]#tar -zvxf nginx-1.10.3.tar.gz
[root@localhost nginx-1.10.3]#./configure \
--prefix=/usr/local/nginx1.10 \
--modules-path=/usr/local/nginx/modules \
--conf-path=/etc/nginx/nginx.conf \
--error-log-path=/var/log/nginx.log \
--pid-path=/var/run/nginx.pid \
--user=nginx --group=nginx \		需要先创建用户、组
--with-http_ssl_module \
--with-http_gunzip_module \
--with-http_gzip_static_module \
--with-http_perl_module \
--with-ld-opt="-L,/usr/local/lib"		支持perl模块时必须安装，否则启动服务会报错
[root@localhost nginx-1.10.3]#make && make install
[root@localhost ~]#sed -i '$aexport PATH=/usr/local/nginx1.10/sbin:$PATH' /etc/profile
[root@localhost ~]#source /etc/profile		指定Nginx环境变量并生效
[root@localhost ~]#nginx -c /etc/nginx/nginx.conf
[root@localhost ~]#netstat -atnlp
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      14156/nginx: master

通过浏览器便可访问Nginx测试页面

2、安装配置php-fpm

[root@localhost ~]#yum install -y php-fpm php-mysql
[root@localhost ~]#systemctl start php-fpm.service
[root@localhost ~]#netstat -atnlp
tcp        0      0 127.0.0.1:9000          0.0.0.0:*               LISTEN      1462/php-fpm: maste
[root@localhost ~]#vim /etc/php-fpm.d/www.conf
; Start a new pool named 'www'.
[www]
listen = 127.0.0.1:9000
listen.allowed_clients = 127.0.0.1
user = apache
group = apache
……
默认情况下，php-fpm监听本地127.0.0.1：9000地址

3、配置Nginx支持php-fpm解析

[root@localhost ~]#vim /etc/nginx/nginx.conf
	……
	server {
	        listen       80;
	        server_name  localhost;
	        charset utf-8;	支持简体中文字符
	        root    html;	根目录/usr/local/nginx1.10/html
	        client_max_body_size 50M;
	        #access_log  logs/host.access.log  main;
	        location / {
	            index  index.php index.html index.htm;
	        }
		location ~ \.php$ {
	            fastcgi_pass   127.0.0.1:9000;
	            fastcgi_index  index.php;
	            fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name;	当root在server段定义后，此处可以修改为$document_root来定位文件位置
	            include        fastcgi_params;
	        	}
		}
	……

4、配置本地网络实现lvs_dr模式

创建如下脚本,修改内核参数执行：
[root@localhost ~]#vim dr.sh
	#!/bin/bash
	VIP=192.168.101.200
	case $1 in
	start)
		ifconfig lo:0 $VIP netmask 255.255.255.255 broadcast $VIP
		route add -host $VIP dev lo:0
		echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore
		echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce
		echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore
		echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce
		sysctl -p  >/dev/null 2>&1
		echo "The VIP configure successful!"
	;;
	stop)
		ifconfig lo:0 down
		route del -host $VIP dev lo:0	
		echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore
		echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore
		echo 0 > /proc/sys/net/ipv4/conf/lo/arp_ignore
		echo 0 > /proc/sys/net/ipv4/conf/lo/arp_ignore
		sysctl -p > /dev/null 2>&1
		echo "The VIP deleted!"
	;;
	*)
		echo "usage:please choose options {start|stop}"
	;;
	esac
[root@localhost ~]#chmod +x dr.sh
[root@localhost ~]#./dr.sh start
[root@localhost ~]#ifconfig
	lo:0: flags=73

5、本地添加NFS共享目录

[root@localhost ~]#yum install -y nfs-utils
[root@localhost ~]#mkdir /www
[root@localhost ~]#vim /etc/fstab	添加一条挂载信息
192.168.101.151:/www	/www	nfs	defaults	0 0
[root@localhost ~]#mount -t nfs 192.168.101.151:/www /www

以上相同操作再部署一台RS服务器，IP地址192.168.101.202

基于keepalived实现lvs_dr模式负载均衡

1、配置keepalived

在原有高可用基础上，增加虚拟服务器及realserver
[root@localhost ~]#vim /etc/keepalived/keepalived.conf
	virtual_server 192.168.101.200 80 {
	    delay_loop 6
	    lb_algo rr
	    lb_kind DR
	    persistence_timeout 50
	    protocol TCP
	    real_server 192.168.101.201 80 {
	        weight 1
	        TCP_CHECK {		监控服务状态方式，类似的还有SSL_GET\HTTP_GET等
	            connect_port 80	监控的端口
	            connect_timeout 3
	            nb_get_retry 3
	            delay_before_retry 3
	        }
	    }
	    real_server 192.168.101.202 80 {
	        weight 1
	        TCP_CHECK {
	            connect_port 80
	            connect_timeout 3
	            nb_get_retry 3
	        }
	    }
	}
以上代码需要在主备上均配置添加
[root@localhost ~]#systemctl restart keepalived
[root@localhost ~]#ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  192.168.101.200:80 rr persistent 50
  -> 192.168.101.201:80           Route   1      0          0         
  -> 192.168.101.202:80           Route   1      0          0 

部署wordpress个人网站

1、官网下载wordpress安装包，解压至NFS服务器/www目录下

[root@localhost ~]#cd /www
[root@localhost www]#tar -zvxf wordpress-4.9.1-zh_CN.tar.gz
[root@localhost www]#cd wordpress
[root@localhost wordpress]#cp wp-config-sample.php wp-config.php{,.bak}

2、配置数据库信息

[root@localhost wordpress]#vim wp-config.php
define('DB_NAME', 'wordpress');
define('DB_USER', 'root');
define('DB_PASSWORD', '********');
define('DB_HOST', '192.168.101.151');
define('DB_CHARSET', 'utf8');

define("FS_METHOD","direct");
define("FS_CHMOD_DIR", 0777);
define("FS_CHMOD_FILE", 0777);

3、配置Nginx访问目录

在两台RS服务器上修改nginx.conf
[root@localhost ~]#vim /etc/nginx/nginx.conf
	server {
	        listen       80;
	        server_name  localhost;
	        charset utf-8;	
	        root    /www/wordpress;	
	        client_max_body_size 50M;
		……
		}

4、开启wordpress之旅