Suppose we have a scenario in which all servers share the same configuration file, we can't maintain each server manually. At this time, we can use the configuration management function of zookeeper.

Environment: python + nginx + zookeeper

Objective: when the configuration file in zookeeper changes, nginx automatically pulls the latest configuration file and applies it to the local area. Restart the server in the middle:

One. Build a zookeeper cluster:

For details, please refer to: http://zookeeper.apache.org/doc/r3.4.13/zookeeper started.html

Make sure the zookeeper cluster is healthy:

Two. Install nginx

yum install nginx -y

Start nginx: systemctl start nginx

Three. Write the python zookeeper client:

Objective: to connect the zookeeper cluster regularly and detect the change of configuration file:

from kazoo.client import KazooClient
import time
zk=KazooClient(hosts='192.168.85.137:2181')
zk.start()

Version=None
while True:
    @zk.DataWatch("/nginx")
    def watch_node(data, stat):
        global Version
        if Version == None:
            Version=stat
        if Version != stat:
           Version = stat
           nginx_file=str(data,encoding='utf-8')
           print("Configuration changed!!!!!")
           f=open('nginx.conf','w',encoding='utf-8')
           f.write(nginx_file)
           f.flush()
           f.close()
           import os
           Path=os.path.dirname(os.path.abspath(__file__))
           os.system('cp -f %s/nginx.conf /etc/nginx/nginx.conf && systemctl restart nginx.service'%Path)   #Replace the nginx configuration file, and then restart the service. Note that this is just a general framework. The production environment must not be restarted directly. You can write some judgments. At least you should make sure that the configuration file is free of errors before restarting nginx
        time.sleep(3)

Test: modify nginx configuration in zookeeper to see if the client can pull the configuration file:

from kazoo.client import KazooClient
import time
zk=KazooClient(hosts='192.168.85.137:2181')
zk.start()

nginx_config="""
user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;
include /usr/share/nginx/modules/*.conf;
events {
    worker_connections 1024;
}
http {
    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  /var/log/nginx/access.log  main;
    sendfile            on;
    tcp_nopush          on;
    tcp_nodelay         on;
    keepalive_timeout   65;
    types_hash_max_size 2048;
    include             /etc/nginx/mime.types;
    default_type        application/octet-stream;
    include /etc/nginx/conf.d/*.conf;
    server {
        listen       5555 default_server;
        index index.php index.html;
        server_name  _;
        root         /usr/share/nginx/html;
        include /etc/nginx/default.d/*.conf;

location ~ \.php$ {
            fastcgi_pass   127.0.0.1:9000;
            fastcgi_index  index.php;
            #fastcgi_param  SCRIPT_FILENAME  /scripts$fastcgi_script_name;
            fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
            fastcgi_split_path_info ^(.+\.php)(/.+)$;
            fastcgi_param PATH_INFO $fastcgi_path_info;
            include        fastcgi_params;
        }

        error_page 404 /404.html;
            location = /40x.html {
        }

        error_page 500 502 503 504 /50x.html;
            location = /50x.html {
        }
    }
}

"""
zk.set('/nginx',bytes(nginx_config,encoding='utf-8'))

success!!!