【Nginx】Nginx在Linux下的入门介绍

Nginx的安装

下载、解压

从Nginx下载安装包，我下的是nginx-1.8.0.tar.gz。解压后的目录为：

[root@blog third_package]# tar -zxf nginx-1.8.0.tar.gz 
[root@blog third_package]# ll nginx-1.8.0
total 652
drwxr-xr-x 6 1001 1001   4096 Jul 23 18:17 auto
-rw-r--r-- 1 1001 1001 249124 Apr 21  2015 CHANGES
-rw-r--r-- 1 1001 1001 379021 Apr 21  2015 CHANGES.ru
drwxr-xr-x 2 1001 1001   4096 Jul 23 18:17 conf
-rwxr-xr-x 1 1001 1001   2478 Apr 21  2015 configure
drwxr-xr-x 4 1001 1001   4096 Jul 23 18:17 contrib
drwxr-xr-x 2 1001 1001   4096 Jul 23 18:17 html
-rw-r--r-- 1 1001 1001   1397 Apr 21  2015 LICENSE
drwxr-xr-x 2 1001 1001   4096 Jul 23 18:17 man
-rw-r--r-- 1 1001 1001     49 Apr 21  2015 README
drwxr-xr-x 8 1001 1001   4096 Jul 23 18:17 src

依赖的软件

安装之前把依赖的软件装上，我这里用YUM：yum -y install gcc gcc-c++ pcre pcre-devel zlib zlib-devel openssl openssl-devel

安装

[root@blog nginx-1.8.0]# pwd
/installation_package/nginx-1.8.0
[root@blog nginx-1.8.0]# 
[root@blog nginx-1.8.0]# ./configure --prefix=/opt/nginx_1

执行./configure后在添加了一个目录objs，--prefix表示安装到此目录，如果不设置默认安装到/usr/local/nginx。

编译工作：

make
make install

启动

用/opt/nginx_1/sbin/nginx启动，默认使用的是安装目录的NGINX_HOME/conf/nginx.conf，也就是/opt/nginx_1/conf/nginx.conf。
当然，也可以使用/opt/nginx_1/sbin/nginx -c /opt/nginx_1/conf/nginx.conf指定配置文件。

Nginx的反向代理

我们常用Nginx做反向代理，在设置反向代理前，应先了解下正向代理和反向代理。

如何设置

将到达Nginx的请求转到后端具体的主机，可通过设置上游服务器和代理转发。比如：

http {
    ...
    upstream myweb {
        server 127.0.0.1:9999;
    }

    server {
        ...
        location /myweb {
            proxy_pass  http://myweb;
        }
    }

}

设置好之后，将上游服务器127.0.0.1:9999也部署好，就可以通过Nginx享受上游服务器的具体服务了。

但要注意请求的信息的转发，比如后端是一台TOMCAT，里面运行一个Servet打印各项参数：

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        StringBuffer sb = new StringBuffer();
        sb.append("request.getProtocol() : " + request.getProtocol()).append("\n");
        sb.append("request.getScheme() : " + request.getScheme()).append("\n");
        sb.append("request.getRemoteAddr() : " + request.getRemoteAddr()).append("\n");
        sb.append("request.getRemoteHost() : " + request.getRemoteHost()).append("\n");
        sb.append("request.getServerPort() : " + request.getServerPort()).append("\n");
        sb.append("request.getRemotePort() : " + request.getRemotePort()).append("\n");
        sb.append("request.getQueryString() : " + request.getQueryString()).append("\n");
        sb.append("request.getRemoteUser() : " + request.getRemoteUser()).append("\n");
        sb.append("request.getMethod() : " + request.getMethod()).append("\n");
        sb.append("request.getLocalAddr() : " + request.getLocalAddr()).append("\n");
        sb.append("request.getLocalName() : " + request.getLocalName()).append("\n");
        sb.append("request.getPathInfo() : " + request.getPathInfo()).append("\n");
        sb.append("request.getRequestURI() : " + request.getRequestURI()).append("\n");
        sb.append("request.getRequestURL() : " + request.getRequestURL()).append("\n");
        sb.append("request.getContextPath() : " + request.getContextPath()).append("\n");
        
        response.getWriter().append("Served at: ").append(request.getContextPath()).append("\n").append(sb);
    }

直接访问TOMCAT，http://nick-huang.com:9999/myweb/PrintEnvInfoServlet?keyword=hello-world，打印的信息是这样的：

Served at: /myweb
request.getProtocol() : HTTP/1.1
request.getScheme() : http
request.getRemoteAddr() : 客户端IP
request.getRemoteHost() : 客户端IP
request.getServerPort() : 9999
request.getRemotePort() : 64494
request.getQueryString() : keyword=hello-world
request.getRemoteUser() : null
request.getMethod() : GET
request.getLocalAddr() : 服务端IP
request.getLocalName() : 服务端IP
request.getPathInfo() : null
request.getRequestURI() : /myweb/PrintEnvInfoServlet
request.getRequestURL() : http://nick-huang.com:9999/myweb/PrintEnvInfoServlet
request.getContextPath() : /myweb

只作反向代理的设置，访问NGINX，https://nick-huang.com:777/myweb/PrintEnvInfoServlet?keyword=hello-world，后打印：

Served at: /myweb
request.getProtocol() : HTTP/1.0
request.getScheme() : http
request.getRemoteAddr() : 127.0.0.1
request.getRemoteHost() : 127.0.0.1
request.getServerPort() : 80
request.getRemotePort() : 54856
request.getQueryString() : keyword=hello-world
request.getRemoteUser() : null
request.getMethod() : GET
request.getLocalAddr() : 127.0.0.1
request.getLocalName() : localhost
request.getPathInfo() : null
request.getRequestURI() : /myweb/PrintEnvInfoServlet
request.getRequestURL() : http://myweb/myweb/PrintEnvInfoServlet
request.getContextPath() : /myweb

反向代理后的请求头信息传递

可以发现，反向代理后Protocol、RemoteAddr、ServerPort、RequestURL等参数均有所不同，那么我们需要设置代理时传递参数。
Nginx配置：

    upstream myweb {
        server 127.0.0.1:9999;
        keepalive 32;
    }
    ...
        location /myweb {
            proxy_set_header Host $host:$server_port;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header REMOTE-HOST $remote_addr;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto $scheme;
            proxy_http_version 1.1;
            proxy_set_header Connection "";
            proxy_pass  http://myweb;
        }

相关说明，请点击链接：proxy_http_version、keepalive。

Tomcat的/conf/server.xml的Host节点下添加：

<Valve className="org.apache.catalina.valves.RemoteIpValve" remoteIpHeader="X-Forwarded-For" protocolHeader="X-Forwarded-Proto" protocolHeaderHttpsValue="https" httpsServerPort="777" />

相关说明，请点击链接：org.apache.catalina.valves Class RemoteIpValve

访问https://nick-huang.com:777/myweb/PrintEnvInfoServlet?keyword=hello-world，日志是这样的：

Served at: /myweb
request.getProtocol() : HTTP/1.1
request.getScheme() : https
request.getRemoteAddr() : 客户端IP
request.getRemoteHost() : 客户端IP
request.getServerPort() : 777
request.getRemotePort() : 55022
request.getQueryString() : keyword=hello-world
request.getRemoteUser() : null
request.getMethod() : GET
request.getLocalAddr() : 127.0.0.1
request.getLocalName() : localhost
request.getPathInfo() : null
request.getRequestURI() : /myweb/PrintEnvInfoServlet
request.getRequestURL() : https://nick-huang.com:777/myweb/PrintEnvInfoServlet
request.getContextPath() : /myweb