nginx quick start

A brief introduction to nginx:

(Learning video sharing: Introduction to Programming)

Nginx (engine x) is a Lightweight web server, reverse proxy server and email (IMAP/POP3) proxy server. It was developed in C by Igor Sysoev from Russia while working for Rambler Media.

Igor Sysoev open sourced the Nginx code and gave it the freest 2-clause BSD-like license. Because Nginx uses an event-driven architecture that can handle millions of TCP connections concurrently, its highly modular design and free license have led to the endless emergence of third-party modules that extend Nginx functions, and excellent design brings excellent stability. , so it is widely used as a web server on large-traffic websites.

The so-called reverse proxy (Reverse Proxy) method refers to using a proxy server to accept connection requests on the Internet, then forwarding the request to the server on the internal network, and returning the results obtained from the server to the Internet When a client requests a connection, the proxy server appears as a reverse proxy server to the outside world.

Since there is a reverse proxy, there is also a forward proxy. A forward proxy is a server between the client and the original server. In order to obtain content from the original server, the client sends a request to the proxy and specifies the target. The proxy then forwards the request to the original server and returns the obtained content to the client. .

It can be said that the forward proxy represents the client, and the reverse proxy represents the server.

Using Nginx has the following advantages:

Dependent library

Now servers generally use Linux Operating system, before compiling and installing Nginx, you need to install its dependent libraries.

The following lists several libraries necessary to complete the most basic functions of the Web server.

GCC

GCC (GNU Compiler Collection) can be used to compile C language programs.

Nginx usually does not directly provide binary executable programs, so we need to compile its source code.

And we may use C to write the Nginx HTTP module, then we need to use the G compiler.

Use yum to install the G compiler:

yum install -y gcc-c++

PCRE

PCRE library PCRE (Perl Compatible Regular Expressions, Perl compatible regular expressions) is a function library developed by Philip Hazel , currently used by many software, this library supports regular expressions. It evolved from RegEx. In fact, Perl regular expressions also originated from RegEx written by Henry Spencer.

If we use regular expressions in the configuration file nginx.conf, then the PCRE library must be compiled into Nginx when compiling Nginx, because Nginx's HTTP module relies on it to parse regular expressions.

Of course, if you confirm that you will not use regular expressions, you do not need to install it.

The yum installation method is as follows:

yum install -y pcre pcre-devel

pcre-devel is the development library required for secondary development using PCRE, including header files, etc., which is also required to compile Nginx.

zlib library

The zlib library is used to compress the contents of HTTP packets in gzip format. If we configure gzip on in nginx.conf, and specify that for certain types (content- type) HTTP response uses gzip for compression to reduce network transmission volume, then zlib must be compiled into Nginx during compilation.

The yum installation method is as follows

yum install -y zlib zlib-devel

Similarly, zlib is a library for direct use, and zlib-devel is a library required for secondary development.

OpenSSL Development Library

If our server not only needs to support HTTP, but also needs to transmit HTTP on the more secure SSL protocol, then we need to have OpenSSL.

In addition, if we want to use hash functions such as MD5 and SHA1, we also need to install it.

The yum installation method is as follows:

yum install -y openssl openssl-devel

Download the source code package

Enter the download interface of the Nginx official site and select the latest stable version.

Then use the wget command to download:

[root@host nginx]# wget http://nginx.org/download/nginx-1.16.0.tar.gz
--2019-05-23 03:28:52--  http://nginx.org/download/nginx-1.16.0.tar.gz
Resolving nginx.org... 62.210.92.35, 95.211.80.227, 2001:1af8:4060:a004:21::e3
Connecting to nginx.org|62.210.92.35|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 1032345 (1008K) [application/octet-stream]
Saving to: “nginx-1.16.0.tar.gz”

100%[==========================================================================================================================================>] 1,032,345    715K/s   in 1.4s    

2019-05-23 03:28:53 (715 KB/s) - “nginx-1.16.0.tar.gz” saved [1032345/1032345]

Unzip the file:

[root@host nginx]# tar xf nginx-1.16.0.tar.gz 
[root@host nginx]# ls
nginx-1.16.0  nginx-1.16.0.tar.gz
[root@host nginx]# cd nginx-1.16.0
[root@host nginx-1.16.0]# ls
auto  CHANGES  CHANGES.ru  conf  configure  contrib  html  LICENSE  man  README  src

Compile and install

Compile and install Nginx using the following three commands:

./configure make make install

If the library you depend on cannot be found, an error will be reported when executing the ./configure command. For example, the PCRE library cannot be found:

./configure: error: the HTTP rewrite module requires the PCRE library.
You can either disable the module by using --without-http_rewrite_module
option, or install the PCRE library into the system, or build the PCRE library
statically from the source with nginx by using --with-pcre= option.

The normal output should be as follows, and a Makefile is generated. ：

[root@host nginx-1.16.0]# ./configure
checking for OS
 + Linux 4.10.4-1.el6.elrepo.i686 i686
checking for C compiler ... found
 + using GNU C compiler
 + gcc version: 4.4.7 20120313 (Red Hat 4.4.7-23) (GCC) 
checking for gcc -pipe switch ... found
checking for -Wl,-E switch ... found
checking for gcc builtin atomic operations ... found
checking for C99 variadic macros ... found
checking for gcc variadic macros ... found
checking for gcc builtin 64 bit byteswap ... found
checking for unistd.h ... found
checking for inttypes.h ... found
checking for limits.h ... found
checking for sys/filio.h ... not found
checking for sys/param.h ... found
checking for sys/mount.h ... found
checking for sys/statvfs.h ... found
checking for crypt.h ... found
checking for Linux specific features
checking for epoll ... found
checking for EPOLLRDHUP ... found
checking for EPOLLEXCLUSIVE ... not found
checking for O_PATH ... not found
checking for sendfile() ... found
checking for sendfile64() ... found
checking for sys/prctl.h ... found
checking for prctl(PR_SET_DUMPABLE) ... found
checking for prctl(PR_SET_KEEPCAPS) ... found
checking for capabilities ... found
checking for crypt_r() ... found
checking for sys/vfs.h ... found
checking for nobody group ... found
checking for poll() ... found
checking for /dev/poll ... not found
checking for kqueue ... not found
checking for crypt() ... not found
checking for crypt() in libcrypt ... found
checking for F_READAHEAD ... not found
checking for posix_fadvise() ... found
checking for O_DIRECT ... found
checking for F_NOCACHE ... not found
checking for directio() ... not found
checking for statfs() ... found
checking for statvfs() ... found
checking for dlopen() ... not found
checking for dlopen() in libdl ... found
checking for sched_yield() ... found
checking for sched_setaffinity() ... found
checking for SO_SETFIB ... not found
checking for SO_REUSEPORT ... found
checking for SO_ACCEPTFILTER ... not found
checking for SO_BINDANY ... not found
checking for IP_TRANSPARENT ... found
checking for IP_BINDANY ... not found
checking for IP_BIND_ADDRESS_NO_PORT ... not found
checking for IP_RECVDSTADDR ... not found
checking for IP_SENDSRCADDR ... not found
checking for IP_PKTINFO ... found
checking for IPV6_RECVPKTINFO ... found
checking for TCP_DEFER_ACCEPT ... found
checking for TCP_KEEPIDLE ... found
checking for TCP_FASTOPEN ... not found
checking for TCP_INFO ... found
checking for accept4() ... found
checking for eventfd() ... found
checking for int size ... 4 bytes
checking for long size ... 4 bytes
checking for long long size ... 8 bytes
checking for void * size ... 4 bytes
checking for uint32_t ... found
checking for uint64_t ... found
checking for sig_atomic_t ... found
checking for sig_atomic_t size ... 4 bytes
checking for socklen_t ... found
checking for in_addr_t ... found
checking for in_port_t ... found
checking for rlim_t ... found
checking for uintptr_t ... uintptr_t found
checking for system byte ordering ... little endian
checking for size_t size ... 4 bytes
checking for off_t size ... 8 bytes
checking for time_t size ... 4 bytes
checking for AF_INET6 ... found
checking for setproctitle() ... not found
checking for pread() ... found
checking for pwrite() ... found
checking for pwritev() ... found
checking for sys_nerr ... found
checking for localtime_r() ... found
checking for clock_gettime(CLOCK_MONOTONIC) ... not found
checking for clock_gettime(CLOCK_MONOTONIC) in librt ... found
checking for posix_memalign() ... found
checking for memalign() ... found
checking for mmap(MAP_ANON|MAP_SHARED) ... found
checking for mmap("/dev/zero", MAP_SHARED) ... found
checking for System V shared memory ... found
checking for POSIX semaphores ... not found
checking for POSIX semaphores in libpthread ... found
checking for struct msghdr.msg_control ... found
checking for ioctl(FIONBIO) ... found
checking for struct tm.tm_gmtoff ... found
checking for struct dirent.d_namlen ... not found
checking for struct dirent.d_type ... found
checking for sysconf(_SC_NPROCESSORS_ONLN) ... found
checking for sysconf(_SC_LEVEL1_DCACHE_LINESIZE) ... found
checking for openat(), fstatat() ... found
checking for getaddrinfo() ... found
checking for PCRE library ... found
checking for PCRE JIT support ... not found
checking for zlib library ... found
creating objs/Makefile

Configuration summary
  + using system PCRE library
  + OpenSSL library is not used
  + using system zlib library

  nginx path prefix: "/usr/local/nginx"
  nginx binary file: "/usr/local/nginx/sbin/nginx"
  nginx modules path: "/usr/local/nginx/modules"
  nginx configuration prefix: "/usr/local/nginx/conf"
  nginx configuration file: "/usr/local/nginx/conf/nginx.conf"
  nginx pid file: "/usr/local/nginx/logs/nginx.pid"
  nginx error log file: "/usr/local/nginx/logs/error.log"
  nginx http access log file: "/usr/local/nginx/logs/access.log"
  nginx http client request body temporary files: "client_body_temp"
  nginx http proxy temporary files: "proxy_temp"
  nginx http fastcgi temporary files: "fastcgi_temp"
  nginx http uwsgi temporary files: "uwsgi_temp"
  nginx http scgi temporary files: "scgi_temp"

Check Nginx version

After successful installation, you can check the Nginx version through the -v parameter.

[root@host sbin]# /usr/local/nginx/sbin/nginx -v nginx version: nginx/1.16.0

Startup

Nginx supports direct startup and startup with parameters, which are demonstrated below.

Port occupancy

Nginx needs to use port 80. If port 80 is occupied, the following error will be reported at startup:

nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)

You can use the lsof tool to check the port occupancy. If you If it is not installed, you can use the following command to install it:

yum install -y lsof

Check the occupancy of port 80 on this machine and kill the occupied process:

[root@host sbin]# lsof -i :80
COMMAND  PID USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
java    1765 root   53u  IPv6  15062      0t0  TCP *:http (LISTEN)
[root@host sbin]# killall -9 java
[root@host sbin]# lsof -i :80
[root@host sbin]#

Start by default

使用whereis命令查看nginx的安装目录：

[root@host nginx-1.16.0]# whereis nginx
nginx: /usr/local/nginx

如果不加任何参数启动，会使用默认的nginx.conf配置文件启动Nginx:

/usr/local/nginx/sbin/nginx

启动成功以后，再请求服务器的时候可以看到包含下面内容的网页:

Welcome to nginx!
If you see this page, the nginx web server is successfully installed and working. Further configuration is required.

For online documentation and support please refer to nginx.org.
Commercial support is available at nginx.com.

Thank you for using nginx.

带参数启动

-c参数指定配置文件的启动方式：

./nginx -c mynginx.conf

-p参数指定Nginx的安装目录：

./nginx -p mydir/nginx

-g参数临时指定一些全局配置项

./nginx -g "pid varnginx/test.pid;"

上面这行命令意味着会把pid文件写到varnginx/test.pid中。

-g参数的约束条件是指定的配置项不能与默认路径下的nginx.conf中的配置项相冲突，否则无法启动。

就像上例那样，类似这样的配置项：pid logs/nginx.pid，是不能存在于默认的nginx.conf中的。

另一个约束条件是，以-g方式启动的Nginx服务执行其他命令行时，需要把-g参数也带上，否则可能出现配置项不匹配的情形。

在不启动Nginx的情况下，使用-t参数仅测试配置文件是否有错误。 例如：

./nginx -t

执行结果中显示配置是否正确。

[root@host sbin]# ./nginx -t
nginx: the configuration file /usr/local/nginx/conf/nginx.conf syntax is ok
nginx: configuration file /usr/local/nginx/conf/nginx.conf test is successful

测试配置选项时，使用-q参数可以不把error级别以下的信息输出到屏幕。 例如：

./nginx -t -q

停止服务

停止Nginx的服务主要有两种方式。

一种是快速停止，即立即停止Nginx服务正在处理的所有网络请求，马上丢弃连接停止服务。

另外一种是平缓地停止，即允许Nginx处理完当前的请求，但不再接收新的请求，之后再关闭连接，停止工作。

快速停止服务

/usr/local/nginx/sbin/nginx -s stop

kill服务

kill -s SIGTERM 进程ID或kill -s SIGINT 进程ID与上面./nginx -s stop命令的效果是一样的。

[root@host sbin]# ps -ef|grep nginx 
root     10568     1  0 04:22 ?        00:00:00 nginx: master process ./nginx
nobody   10569 10568  0 04:22 ?        00:00:00 nginx: worker process
root     10571  5440  0 04:23 pts/1    00:00:00 grep nginx
[root@host sbin]# kill -s SIGINT 10568
[root@host sbin]# ps -ef|grep nginx 
root     10574  5440  0 04:24 pts/1    00:00:00 grep nginx
[root@host sbin]#

优雅地停止服务

如果希望Nginx服务可以正常地处理完当前所有请求再停止服务，那么可以使用-s quit参数来停止服务。

例如：

./nginx -s quit

该命令与快速停止Nginx服务是有区别的。

当快速停止服务时，worker进程与master进程在收到信号后会立刻跳出循环，退出进程。

而“优雅”地停止服务时，首先会关闭监听端口，停止接收新的连接，然后把当前正在处理的连接全部处理完，最后再退出进程。

与快速停止服务相似，可以直接发送QUIT信号给master进程来停止服务，其效果与执行-s quit命令是一样的。

例如：

kill -s SIGQUIT 

如果希望“优雅”地停止某个worker进程，那么可以通过向该进程发送WINCH信号来停止服务 。

例如：

kill -s SIGWINCH 

发送信号

./nginx -g TERM | INT | QUIT

TERM 和 INT 信号用于快速停止，QUIT 信号用于平滑停止。

Nginx重新加载配置

使运行中的Nginx重读配置项并生效

使用-s reload参数可以使运行中的Nginx服务重新加载nginx.conf文件。 例如：

usrlocal/nginx/sbin/nginx -s reload

日志文件回滚

使用-s reopen参数可以重新打开日志文件，这样可以先把当前日志文件改名或转移到其他目录中进行备份，再重新打开时就会生成新的日志文件。

这个功能使得日志文件不至于过大。 例如：

./nginx -s reopen

这与使用kill命令发送USR1信号效果相同。

kill -s SIGUSR1 

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