Nginx tcp proxy module试用

前文Nginx TCP Proxy模块的编译安装描述了如何编译tcp proxy module。现在来实验一下如何用。

首先要创建一个日志目录，因为t该模块的日志默认不在/var/log/nginx目录下

mkdir -p /etc/nginx/logs/

在nginx.conf文件中添加下面一节：

tcp {    upstream tcpend {         server localhost:7778;     check interval=3000 rise=2 fall=5 timeout=1000;    }    server {       listen 7777;          proxy_pass tcpend;    }}

注意，协议是tcp，不能将配置放在http下面。

然后启动本地的某个tcp程序，监听端口7778。用测试程序发起一个7777的连接请求，测试通过。而且不影响http的代理。

但是这个也有副作用，当服务端关闭连接的时候，客户端不可能立刻发觉连接已经被关闭，需要等到：

当Nginx在执行check规则时认为服务端链接关闭，Nginx会关闭与客户端的连接。

此时客户端才能察觉到连接关闭。好在不影响正常连接，所以不是大问题。

对于Nginx内部的工作原理，由于还没有研究过其实现代码，目前只能推测到此。

下面是check命令的解释：

check    syntax: *check interval=milliseconds [fall=count] [rise=count]    [timeout=milliseconds] [type=tcp|ssl_hello|smtp|mysql|pop3|imap]*    default: *none, if parameters omitted, default parameters are    interval=30000 fall=5 rise=2 timeout=1000*    context: *upstream*    description: Add the health check for the upstream servers. At present,    the check method is a simple tcp connect.    The parameters' meanings are:    *   *interval*: the check request's interval time.    *   *fall*(fall_count): After fall_count check failures, the server is        marked down.    *   *rise*(rise_count): After rise_count check success, the server is        marked up.    *   *timeout*: the check request's timeout.    *   *type*: the check protocol type:        1.  *tcp* is a simple tcp socket connect and peek one byte.        2.  *ssl_hello* sends a client ssl hello packet and receives the            server ssl hello packet.        3.  *http* sends a http request packet, receives and parses the http            response to diagnose if the upstream server is alive.        4.  *smtp* sends a smtp request packet, receives and parses the smtp            response to diagnose if the upstream server is alive. The            response begins with '2' should be an OK response.        5.  *mysql* connects to the mysql server, receives the greeting            response to diagnose if the upstream server is alive.        6.  *pop3* receives and parses the pop3 response to diagnose if the            upstream server is alive. The response begins with '+' should be            an OK response.        7.  *imap* connects to the imap server, receives the greeting            response to diagnose if the upstream server is alive.