Server Environment Setup

Host: 4-core 8GB CentOS 7.9 virtual machine (verify with cat /etc/redhat-release) Dependencies: Anaconda, Python 3.8, uWSGI, Nginx

Python 3.8 Compilation and Installation

Update Yum Repositories

First back up default CentOS base repo:

cp /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.bak

Replace with Alibaba Cloud mirror repo:

wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

Generate package metadata cache:

yum makecache fast

Clean old cache optionally:

yum clean packages headers metadata dbcache

Install Build Dependencies

yum groupinstall -y "Development Tools"
yum install -y zlib-devel bzip2-devel openssl11-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel libffi-devel

Download and Extract Python 3.8 Source

cd /tmp
wget https://www.python.org/ftp/python/3.8.18/Python-3.8.18.tgz
tar -xzf Python-3.8.18.tgz

Compile and Install Python 3.8

mkdir -p /opt/python38
cd /tmp/Python-3.8.18
./configure --prefix=/opt/python38 --enable-optimizations
make -j4
make install

Configure System Symlinks

List existing Python-related symlinks:

ls -la /usr/bin/ | grep python

Replace default Python symlink:

rm -f /usr/bin/python
ln -s /opt/python38/bin/python3 /usr/bin/python

Verify Python version:

python --version

Update Pip symlink:

rm -f /usr/bin/pip
ln -s /opt/python38/bin/pip3 /usr/bin/pip

Verify Pip version:

pip --version

Adjust Yum Scripts

Yum relies on Python 2.7, modify shebangs:

vi /usr/bin/yum
# Change first line from #!/usr/bin/python to #!/usr/bin/python2
vi /usr/libexec/urlgrabber-ext-down
# Change first line from #!/usr/bin/python to #!/usr/bin/python2
vi /usr/bin/yum-config-manager
# Change first line from #!/usr/bin/python to #!/usr/bin/python2

Optional Python 3.8 Uninstallation

rpm -qa | grep python3 | xargs rpm -ev --allmatches --nodeps
whereis python3 | xargs rm -frv
whereis python

uWSGI Configuration and Management

Create a config file uwsgi_config.ini in your Flask project root:

[uwsgi]
socket = 127.0.0.1:9090
chdir = /var/www/my_flask_app
wsgi-file = app.py
callable = application
workers = 4
threads = 4
stats = 127.0.0.1:9292
pidfile = /var/www/my_flask_app/uwsgi.pid
daemonize = /var/www/my_flask_app/logs/uwsgi_app.log
lazy-apps = true
vacuum = true
touch-chain-reload = /var/www/my_flask_app/.reload_trigger

uWSGI Control Commands

Start in foreground:

cd /var/www/my_flask_app
uwsgi --ini uwsgi_config.ini

Start as daemon:

uwsgi --ini uwsgi_config.ini --daemonize /var/www/my_flask_app/logs/uwsgi_app.log

Restart service:

uwsgi --reload uwsgi.pid

Gracefully stop service:

uwsgi --stop uwsgi.pid

Hard kill unresponsive processes:

kill -9 $(cat uwsgi.pid)

Nginx Installation and Reverse Proxy Setup

Check and Uninstall Existing Nginx

find / -name nginx -type f 2>/dev/null
yum erase -y nginx nginx-all-modules

Install Nginx Build Dependencies

yum install -y gcc-c++ pcre2-devel zlib-devel openssl-devel

Compile and Install Nginx

Navigate to source directory:

cd /usr/local/src

Download Nginx 1.24.0 source:

wget -c https://nginx.org/download/nginx-1.24.0.tar.gz

Extract and enter directory:

tar -xzf nginx-1.24.0.tar.gz
cd nginx-1.24.0

Configure, compile, and install:

mkdir -p /usr/local/nginx-1.24.0
./configure --prefix=/usr/local/nginx-1.24.0 --with-http_stub_status_module --with-http_ssl_module --with-pcre
make -j4
make install

Create a symlink for easier access:

ln -s /usr/local/nginx-1.24.0/sbin/nginx /usr/sbin/nginx

Configure Nginx Reverse Proxy

Edit main Nginx config:

vi /usr/local/nginx-1.24.0/conf/nginx.conf

Replace default server block with:

server {
    listen 80;
    server_name YOUR_SERVER_PUBLIC_IP_OR_DOMAIN;

    access_log /usr/local/nginx-1.24.0/logs/my_flask_access.log;
    error_log /usr/local/nginx-1.24.0/logs/my_flask_error.log;

    location / {
        include uwsgi_params;
        uwsgi_pass 127.0.0.1:9090;
    }
}

Nginx Control Commands

Start Nginx:

nginx

Test config file syntax:

nginx -t

Reload config without downtime:

nginx -s reload

Gracefullly stop Nginx:

nginx -s quit

Force stop Nginx:

nginx -s stop

Check running Nginx processes:

ps aux | grep nginx