摘要：前提配置環(huán)境變量準備服務器或者虛擬機，以及環(huán)境，這個是必須的前提啊，我相信你可以的。關掉主機，主機監(jiān)控到無后，自動切換

準備centos服務器或者虛擬機，以及JAVA環(huán)境，這個是必須的前提啊，我相信你可以的。

# 下載
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

# 解壓
tar -xvf apache-tomcat-8.5.31.tar.gz 

# 啟動
./apache-tomcat-8.5.31/bin/startup.sh

curl "http://nginx.org/download/nginx-1.14.0.tar.gz" -o nginx-1.14.0.tar.gz
tar -xvf nginx-1.14.0.tar.gz

curl "http://www.zlib.net/zlib-1.2.11.tar.gz" -o zlib-1.2.11.tar.gz
tar -xvf zlib-1.2.11.tar.gz

curl "https://jaist.dl.sourceforge.net/project/pcre/pcre/8.41/pcre-8.41.tar.gz" -o pcre-8.41.tar.gz
tar -xvf pcre-8.41.tar.gz

curl "https://www.openssl.org/source/openssl-1.0.2o.tar.gz" -o openssl-1.0.2o.tar.gz
tar -xvf openssl-1.0.2o.tar.gz

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-1.0.2o

make 

make install

如果有異常：./configure: error: C compiler cc is not found，則安裝gcc等軟件

yum -y install gcc gcc-c++ autoconf automake make

# 最精簡的nginx負載均衡配置，僅15行配置
events {
    # 并發(fā)連接數(shù)
    worker_connections  1024;
}
http {
    # Tomcat服務器集群
    upstream tomcat_servers {
        server 192.168.100.1:8081;
        server 192.168.100.1:8080;
    }
    server {
        # 監(jiān)聽80端口
        listen    80;
        
        # 將所有請求交給Tomcat集群去處理
        location / {
            proxy_pass http://tomcat_servers;
        }
    }
}

# 執(zhí)行命令 /usr/local/nginx/sbin/nginx 就可以啟動啦

接下來就是通過keepalived實現(xiàn)nginx的高可用了

這是我在學習下面這些高并發(fā)分布式技術(shù)時的筆記，不知道怎么發(fā)附件，需要配置文件的話我后續(xù)補上，或者你可以私信我。

yum -y install openssl-devel 
yum -y install libnl libnl-devel
yum install -y libnfnetlink-devel

# 下載
curl "http://www.keepalived.org/software/keepalived-1.4.4.tar.gz" -o keepalived-1.4.4.tar.gz
tar -xvf keepalived-1.4.4.tar.gz

cd keepalived-1.4.4  

# 安裝到/usr/local/keepalived目錄
./configure --prefix=/usr/local/keepalived --sysconf=/etc  
make && make install

配置放在/etc/keepalived/，三份配置文件（一個nginx_monitor監(jiān)控腳本，主備各一份keepalived配置）

# 創(chuàng)建nginx monitor 腳本，并賦予可執(zhí)行權(quán)限
chmod +x /etc/keepalived/nginx_monitor.sh
# 測試一下腳本能不能執(zhí)行
執(zhí)行命令：/etc/keepalived/nginx_monitor.sh 
沒報錯即表示為成功

#  - master主機
keepalived-nginx-master.conf
#  - backup備機
keepalived-nginx-backup.conf

# 啟動master主機
/usr/local/keepalived/sbin/keepalived -f /etc/keepalived/keepalived-nginx-master.conf
# 啟動backup備機
/usr/local/keepalived/sbin/keepalived -f /etc/keepalived/keepalived-nginx-backup.conf

ps -ef | grep keepalived
kill -9  關閉相關的進程

1. 關掉備機，功能完全不受影響。
2. 關掉主機，虛擬IP漂移到備機，備機開始工作。
3. 關掉主機nginx，主機監(jiān)控到無nginx后，自動切換