前提-配置java环境变量
准备centos服务器或者虚拟机，以及JAVA环境，这个是必须的前提啊，我相信你可以的。
tomcat
# 下载curl "http://mirror.bit.edu.cn/apache/tomcat/tomcat-8/v8.5.31/bin/apache-tomcat-8.5.31.tar.gz" -o apache-tomcat-8.5.31.tar.gz# 解压tar -xvf apache-tomcat-8.5.31.tar.gz # 启动./apache-tomcat-8.5.31/bin/startup.sh
nginx
下载及解压 相关的模块到/u01目录
curl "http://nginx.org/download/nginx-1.14.0.tar.gz" -o nginx-1.14.0.tar.gztar -xvf nginx-1.14.0.tar.gzcurl "http://www.zlib.net/zlib-1.2.11.tar.gz" -o zlib-1.2.11.tar.gztar -xvf zlib-1.2.11.tar.gzcurl "https://jaist.dl.sourceforge.net/project/pcre/pcre/8.41/pcre-8.41.tar.gz" -o pcre-8.41.tar.gztar -xvf pcre-8.41.tar.gzcurl "https://www.openssl.org/source/openssl-1.0.2o.tar.gz" -o openssl-1.0.2o.tar.gztar -xvf openssl-1.0.2o.tar.gz
编译安装nginx
cd nginx-1.14.0./configure --prefix=/usr/local/nginx --with-http_ssl_module --with-pcre=../pcre-8.41 --with-zlib=../zlib-1.2.11 --with-openssl=../openssl-1.0.2omake make install
如果有异常：./configure: error: C compiler cc is not found，则安装gcc等软件
yum -y install gcc gcc-c++ autoconf automake make
配置并启动，最精简的nginx负载均衡配置，仅15行配置，直接覆盖conf文件夹下面的nginx.conf
nginx.conf全部内容
接下来就是通过keepalived实现nginx的高可用了
学习感言
这是我在学习下面这些高并发分布式技术时的笔记，不知道怎么发附件，需要配置文件的话我后续补上，或者你可以私信我。
高并发分布式技术学习课程
keepalived
下载安装相关相关的组件
yum -y install openssl-devel yum -y install libnl libnl-develyum install -y libnfnetlink-devel
下载安装keepalived
# 下载curl "http://www.keepalived.org/software/keepalived-1.4.4.tar.gz" -o keepalived-1.4.4.tar.gztar -xvf keepalived-1.4.4.tar.gzcd keepalived-1.4.4 # 安装到/usr/local/keepalived目录./configure --prefix=/usr/local/keepalived --sysconf=/etc make && make install
配置文件存放地址
配置放在/etc/keepalived/，三份配置文件（一个nginx_monitor监控脚本，主备各一份keepalived配置）
nginx监控shell脚本 nginx_monitor.sh 文件
# 创建nginx monitor 脚本，并赋予可执行权限chmod +x /etc/keepalived/nginx_monitor.sh# 测试一下脚本能不能执行执行命令：/etc/keepalived/nginx_monitor.sh 没报错即表示为成功
nginx_monitor.sh
keepalived配置（/etc/keepalived/目录下）
# - master主机keepalived-nginx-master.conf# 放在备机- backup备机keepalived-nginx-backup.conf
keepalived-nginx-master.conf
keepalived-nginx-backup.conf
启动keepalived
# 启动master主机/usr/local/keepalived/sbin/keepalived -f /etc/keepalived/keepalived-nginx-master.conf# 启动backup备机/usr/local/keepalived/sbin/keepalived -f /etc/keepalived/keepalived-nginx-backup.conf
停止
ps -ef | grep keepalivedkill -9 关闭相关的进程
测试高可用
1. 关掉备机，功能完全不受影响。2. 关掉主机，虚拟IP漂移到备机，备机开始工作。3. 关掉主机nginx，主机监控到无nginx后，自动切换
