1. Introduction to Nginx

2. Installation Methods

3. I/O Models and Zero-Copy Technology

4. Process Architecture

5. Configuration Optimization

6. Smooth Upgrade Procedures

7. Introduction to Nginx

Nginx is a high-performance web server developed in 2002 by Russian engineers for Rambler.ru. Acquired by F5 in 2019 for $670M, it's used by major internet companies like Taobao, JD.com, and Xiaomi. Key features include:

• Reverse proxy and load balancing
• Support for 20k+ concurrent connections
• HTTP/HTTPS/SMTP/POP3/IMAP protocol handling
• FastCGI/URL rewriting/Gzip support
• Stream module for TCP/UDP load balancing (1.9+)

2. Installation Methods

2.1 Yum Installation

yum install epel-release -y
yum install nginx -y

2.2 Repository Configuration

vim /etc/yum.repos.d/nginx.repo
[nginx-stable]
name=nginx stable repo
baseurl=http://nginx.org/packages/centos/$releasever/$basearch/
gpgcheck=1
enabled=1

2.3 Source Compilation

yum install gcc pcre-devel openssl-devel zlib-devel -y
./configure --prefix=/opt/nginx \
--user=nginx \
--group=nginx \
--with-http_ssl_module \
--with-http_v2_module \
--with-http_stub_status_module \
--with-http_gzip_static_module \
--with-pcre \
--with-stream \
--with-stream_ssl_module

make && make install

3. I/O Models and Zero-Copy Technology

3.1 I/O Model Classification

• Blocking I/O: Process waits until I/O completes
• Non-blocking I/O: Immediate response with status checks
• I/O Multiplexing: select/poll/epoll for multiple sockets
• Signal-driven I/O: SIGIO signal notifications
• Asynchronous I/O: Kernel completes I/O before notification

3.2 Zero-Copy Implementation

Reduces data copying between kernel/user space through:

• sendfile() system call
• Memory mapping (mmap)
• Kernel-space data transfer

4. Process Architecture

Nginx uses a master-worker process model:

• Master process: Manages configuration, socket binding, and worker processes
• Worker processes: Handle actual client requests
• Supports graceful shutdown (-s quit) and hot reloading (-s reload)

5. Configuration Optimization

5.1 Core Configuration Parameters

worker_processes auto;
worker_cpu_affinity 00000001 00000010;
worker_rlimit_nofile 65536;
pid /opt/nginx/run/nginx.pid;

5.2 Performance Tuning

• CPU affinity binding for worker processes
• File descripotr limits configuration
• Epoll event model for Linux
• Keep-alive connnection optimizations

6. Smooth Upgrade Procedures

# Download new version
wget https://nginx.org/download/nginx-1.20.2.tar.gz
tar xf nginx-1.20.2.tar.gz
cd nginx-1.20.2

# Recompile without installing
./configure --prefix=/opt/nginx ...
make

# Perform rolling upgrade
mv /opt/nginx/sbin/nginx /opt/nginx/sbin/nginx.old
cp objs/nginx /opt/nginx/sbin/

# Send USR2 signal to master process
kill -USR2 `cat /opt/nginx/logs/nginx.pid`

# Gracefully shut down old workers
kill -WINCH `cat /opt/nginx/logs/nginx.pid.oldbin`

6.1 Rollback Procedure

# Restore previous version
mv /opt/nginx/sbin/nginx.old /opt/nginx/sbin/nginx

# Restart with old binary
kill -HUP `cat /opt/nginx/logs/nginx.pid.oldbin`