Check whether the port number is occupied

netstat -anp | grep 8080
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View the application process

ps aux|grep nginx
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Flask part

  • Flask part
    • Flask: First of all, the writing service part is omitted.

Gunicorn part

  • Gunicorn part

    • First of all, our Flask project is started by:

      • app.run(host="0.0.0.0",use_reloader=True, port=5000)
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    • If we use Gunicorn to boot, instead of writing the port number, we can use Gunicorn to set the port number for boot

      • Flask service startup mode becomes
app.run(debug=False)
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      • Start with Gunicorn

        • Worker 4 threads are 4 threads
gunicorn -w 4 manage:app
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        • # when our app is built using factory functions
gunicorn -w 4 "my_project:create_app()"
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    • Complete the above steps to start the Flask using Gunicorn

The supervisor section

  • The supervisor section

    • The main task is to complete the gunicorn configuration

      • Flask is started by gunicorn using four processes (four threads each)

      • [program:gunicorn]
command=gunicorn -w 4 "manage:create_app()" -b :8091
directory=/home/a21036/waws/PaddleOCR
priority=1
numprocs=1
autostart=true
autorestart=true
startretries=10
exitcodes=0
stopsignal=KILL
stopwaitsecs=10
redirect_stderr=true

[program:gunicorn_1]
command=gunicorn -w 4 "manage:create_app()" -b :8092
directory=/home/a21036/waws/PaddleOCR
priority=1
numprocs=1
autostart=true
autorestart=true
startretries=10
exitcodes=0
stopsignal=KILL
stopwaitsecs=10
redirect_stderr=true

[program:gunicorn_2]
command=gunicorn -w 4 "manage:create_app()" -b :8093
directory=/home/a21036/waws/PaddleOCR
priority=1
numprocs=1
autostart=true
autorestart=true
startretries=10
exitcodes=0
stopsignal=KILL
stopwaitsecs=10
redirect_stderr=true

[program:gunicorn_3]
command=gunicorn -w 4 "manage:create_app()" -b :8094
directory=/home/a21036/waws/PaddleOCR
priority=1
numprocs=1
autostart=true
autorestart=true
startretries=10
exitcodes=0
stopsignal=KILL
stopwaitsecs=10
redirect_stderr=true
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      • Our Supervisor is started without being started using the following command

        • supervisord -c /usr/supervisor/supervisor.conf
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      • If we have started supervisor, we use the following command to start it

        • supervisorctl
start gunicorn
start gunicorn_1
start gunicorn_2
start gunicorn_3
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        • supervisorctl
start all
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Nginx part

  • Nginx part

    • The main consideration is the concurrency of the program, to start the four services, load balancing

      • In /etc/nginx/cond.d, create two new files. Upstream. conf controls the configuration of the actual monitoring port implementation of the distributed file backend.conf

        • upstream.conf

          • upstream backends {
     server localhost:9001;
     server localhost:9002;
     server localhost:9003;
     server localhost:9004;
}
server {
     listen 80; location / { proxy_pass http://backends; }}Copy the code

        • backend.conf

          • server {
     listen localhost:9001;

     location ^~ /static/ {
        alias /home/a21036/static/;
        autoindex on;
     }
     location = /upload {

        proxy_pass http://localhost:8091/upload;
        proxy_redirect off;

        proxy_set_header Host $http_post;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
     }
     location =/ {
         proxy_pass http://localhost:8091/;
         proxy_redirect off;

         proxy_set_header Host $http_post;
         proxy_set_header X-Real-IP $remote_addr;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
     }
}

server {
     listen localhost:9002;

     location ^~ /static/ {
        alias /home/a21036/static/;
        autoindex on;
     }
     location = /upload {

        proxy_pass http://localhost:8092/upload;
        proxy_redirect off;

        proxy_set_header Host $http_post;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
     }
     location =/ {
         proxy_pass http://localhost:8092/;
         proxy_redirect off;

         proxy_set_header Host $http_post;
         proxy_set_header X-Real-IP $remote_addr;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
     }
}

server {
     listen localhost:9003;

     location ^~ /static/ {
        alias /home/a21036/static/;
        autoindex on;
     }
     location = /upload {

        proxy_pass http://localhost:8093/upload;
        proxy_redirect off;

        proxy_set_header Host $http_post;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
     }
     location =/ {
         proxy_pass http://localhost:8093/;
         proxy_redirect off;

         proxy_set_header Host $http_post;
         proxy_set_header X-Real-IP $remote_addr;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
     }
}

server {
     listen localhost:9004;

     location ^~ /static/ {
        alias /home/a21036/static/;
        autoindex on;
     }
     location = /upload {

        proxy_pass http://localhost:8094/upload;
        proxy_redirect off;

        proxy_set_header Host $http_post;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
     }
     location =/ {
         proxy_pass http://localhost:8094/; proxy_redirect off; proxy_set_header Host $http_post; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; }}Copy the code

        • A serious mistake was made in this area:

          • server {
     listen localhost:8094;   # Error source

     location ^~ /static/ {
        alias /home/a21036/static/;
        autoindex on;
     }
     location = /upload {

        proxy_pass http://localhost:8094/upload;
        proxy_redirect off;

        proxy_set_header Host $http_post;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
     }
     location =/ {
         proxy_pass http://localhost:8094/; proxy_redirect off; proxy_set_header Host $http_post; proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; }}Copy the code

          • Actual error causes: We used Supervisor to start Gunicorn, and started the service of 8094. Then we used Nginx to listen to 8094, but the port was occupied. We need to use other ports to monitor 8094

    • Our nginx does not start with the following command

      • systemctl start nginx
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    • If we have started nginx, we use the following command to reload the configuration file

      • # Check our nginx configuration syntax for errors
/usr/sbin/nginx -t

Reload the configuration file
/usr/sbin/nginx -s reload
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The other parts

  • Other:

    • When we have a problem with the configuration, we can use the specified log location in the configuration file to find the log, check the log can find the problem, the following uses nginx log as an example

    • # View method 1
tail -F xxxx.log    # Newly generated logs are viewed in a scrolling mode

# View method 2
vim xxxx.log       View logs in full
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    • Nginx has two main logs placed in /var/log/nginx

      • access.log
      • error.log
        • We can see that the previous configuration of port occupancy was incorrect