Introduction to nginx architecture principle and deployment configuration
In the currently participating projects, nginx is used as a reverse proxy, load balancing, access to static files, and communication encryption using https, etc. Therefore, here is a summary of nginx's related architecture principles, installation, deployment, configuration and use, etc., for follow-up Continue to conduct in-depth research and study and provide reference for latecomers. There are inevitably omissions in the article, and I hope readers will give criticism and corrections, thank you very much!
1. Introduction to nginx
nginx is an open source, cross-platform high-performance web server developed by Russian programmer Igor Sysoev; it
has the advantages of high performance, high stability, simple configuration, modular structure, and low resource consumption; it
supports reverse Proxy, load balancing, and cache functions;
it adopts the multi-process + epoll (IO multiplexing) model, and also has good support for Internet high-concurrency connection services.
2. nginx architecture
Simple nginx architecture:
After nginx starts, it will run in the background as a daemon in the Unix system. The background process includes a master process and multiple worker processes.
(1) Master process
The master process is mainly used to manage the worker process, including: receiving signals from the outside world, sending signals to each worker process, monitoring the running status of the worker process, and automatically restarting when the worker process exits (under abnormal circumstances). Start a new worker process.
(2) Worker process
Basic network events are handled in the worker process. Multiple worker processes are peer-to-peer, and they compete equally for requests from clients, and each process is independent of each other. The number of worker processes can be set, and the general setting is consistent with the number of CPU cores of the machine. The reason for this is inseparable from the process model and event processing model of nginx.
(3) High performance of nginx
First, it adopts a multi-process model. For each worker process, an independent process does not need to be locked, which saves the overhead caused by locks;
second, nginx supports epoll to handle connections ( I/O multiplexing method).
3. nginx installation and deployment
(1) Install gcc
gcc -v
yum -y install gcc
(2) pcre, pcre-devel installation
pcre是一个perl库，包括perl兼容的正则表达式库，nginx的http模块使用pcre来解析正则表达式，所以需要安装pcre库。
yum install -y pcre pcre-devel
(3) zlib installation
zlib库提供了很多种压缩和解压缩方式nginx使用zlib对http包的内容进行gzip，所以需要安装
安装命令：
yum install -y zlib zlib-devel
(4) Install openssl
openssl是web安全通信的基石
安装命令：
yum install -y openssl openssl-devel
(5) Install nginx
1、下载nginx安装包，官网下载地址 https://nginx.org/en/download.html
wget https://nginx.org/download/nginx-1.20.1.tar.gz
2、把压缩包解压到usr/local/
tar -zxvf nginx-1.20.1.tar.gz
3、切换到cd /usr/local/nginx-1.20.1下面
执行三个命令：
./configure --prefix=/usr/local/nginx --with-http_ssl_module --with-http_stub_status_module --with-http_gzip_static_module
make
make install
4、切换到/usr/local/nginx安装目录conf文件，配置文件nginx.conf，调整端口配置
5、启动nginx服务
切换目录到/usr/local/nginx/sbin下面
启动nginx命令：
./nginx
6、查看nginx服务是否启动成功
ps -ef | grep nginx
(6) nginx add module
1、判断模块是否安装
/usr/local/nginx/sbin/nginx -V
2、进入安装解压包重新配置
./configure --with-http_stub_status_module --with-http_ssl_module
其中 --with-http_ssl_module 就是ssl模块
3、编译
make
不要使用make install指令，否则就是覆盖安装。
4、替换nginx二进制文件:
cp ./objs/nginx /usr/local/nginx/sbin/
5、检验
[root@localhost objs]# ./nginx -V
nginx version: nginx/1.20.1
built by gcc 4.8.5 20150623 (Red Hat 4.8.5-44) (GCC)
built with OpenSSL 1.0.2k-fips 26 Jan 2017
TLS SNI support enabled
configure arguments: --with-http_stub_status_module --with-http_ssl_module
4. nginx common commands
（1）启动nginx： nginx
（2）以特定目录下的配置文件启动：nginx -c /特定目录/nginx.conf
（3）重新加载配置：nginx -s reload
执行这个命令后，master进程会等待worker进程处理完当前请求，然后根据最新配置重新创建新的worker进程，完成Nginx配置的热更新。
（4）立即停止服务： nginx -s stop
（5）从容停止服务： nginx -s quit
执行该命令后，Nginx在完成当前工作任务后再停止。
（6）检查配置文件是否正确 ： nginx -t
（7）检查特定目录的配置文件是否正确： nginx -t -c /特定目录/nginx.conf
（8）查看版本信息： nginx -v
5. nginx configuration instructions
5.1 Configuration file structure
#user nobody;
worker_processes 1;
#error_log logs/error.log;
#error_log logs/error.log notice;
#error_log logs/error.log info;
#pid logs/nginx.pid;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
#log_format main '$remote_addr - $remote_user [$time_local] "$request" '
# '$status $body_bytes_sent "$http_referer" '
# '"$http_user_agent" "$http_x_forwarded_for"';
#access_log logs/access.log main;
sendfile on;
#tcp_nopush on;
#keepalive_timeout 0;
keepalive_timeout 65;
#gzip on;
server {
listen 80;
server_name localhost;
#charset koi8-r;
#access_log logs/host.access.log main;
location / {
root html;
index index.html index.htm;
}
#error_page 404 /404.html;
# redirect server error pages to the static page /50x.html
#
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
# proxy the PHP scripts to Apache listening on 127.0.0.1:80
#
#location ~ \.php$ {
# proxy_pass http://127.0.0.1;
#}
# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
#
#location ~ \.php$ {
# root html;
# fastcgi_pass 127.0.0.1:9000;
# fastcgi_index index.php;
# fastcgi_param SCRIPT_FILENAME /scripts$fastcgi_script_name;
# include fastcgi_params;
#}
# deny access to .htaccess files, if Apache's document root
# concurs with nginx's one
#
#location ~ /\.ht {
# deny all;
#}
}
# another virtual host using mix of IP-, name-, and port-based configuration
#
#server {
# listen 8000;
# listen somename:8080;
# server_name somename alias another.alias;
# location / {
# root html;
# index index.html index.htm;
# }
#}
# HTTPS server
#
#server {
# listen 443 ssl;
# server_name localhost;
# ssl_certificate cert.pem;
# ssl_certificate_key cert.key;
# ssl_session_cache shared:SSL:1m;
# ssl_session_timeout 5m;
# ssl_ciphers HIGH:!aNULL:!MD5;
# ssl_prefer_server_ciphers on;
# location / {
# root html;
# index index.html index.htm;
# }
#}
}
5.2 Reverse proxy configuration
location /api {
proxy_pass http://192.168.65.128:10001/api;
}
5.3 Load balancing configuration
By default, nginx supports multiple load balancing strategies such as polling, weight, and ip Hash.
Polling: The default setting method, each request is assigned to different back-end servers for processing in chronological order, and downtime servers can be automatically eliminated.
Weight method: Use weight to specify the weight ratio of polling, which is used in the case of uneven performance of back-end servers.
ip_hash method: Each request is assigned according to the hash result of the IP, so that each visitor can access the same backend server for each request, which can solve the problem of session sharing.
upstream api_servers {
（ip_hash;）
server 192.168.65.128 （weight=1）;
server 192.168.65.129（weight=3）;
}
location /api {
proxy_pass http://api_servers;
}
5.4 Static file configuration
（1）root的处理结果是：root路径 + location路径
（2）alias的处理结果是：使用alias路径替换location路径
（3）try_files，是在对vue-router进行History模式进行配置时
location / {
try_files $uri $uri/ /index.html;
}
关键点1：按指定的file顺序查找存在的文件，并使用第一个找到的文件进行请求处理
关键点2：查找路径是按照给定的root或alias为根路径来查找的
关键点3：如果给出的file都没有匹配到，则重新请求最后一个参数给定的uri，就是新的location匹配
例如：
location /img/ {
root /opt/html/;
try_files $uri $uri/ /img/default.gif;
}
比如 请求 127.0.0.1/img/test.gif 会依次查找 ：
1.文件/opt/html/img/test.gif
2.文件夹 /opt/html/img/test.gif/下的index文件
3. 请求127.0.0.1/img/default.gif
6. References
[1] https://www.nginx.com/
[2] https://blog.51cto.com/longlei/2130185
[3] https://www.cnblogs.com/jasonbourne3/p/14099717.html
[4] https://blog.csdn.net/qq_37345604/article/details/90034424
[5] https://blog.csdn.net/buyueliuying/article/details/89676892
[6] https://blog.csdn.net/duola8789/article/details/107608658