I can't communicate between 2 dockers that connected to the same network-CodePudding

I have 2 dockers, one is the client and the other is the server.

After deployment, I can't reach the server from the client.

Here is my docker-compose file:

version: "3"

services:
  # should be locate once in the control node
  log_server:
    build: ./logServer/
    restart: unless-stopped
    ports:
      - "4000:80"
    networks:
      - logging-net
    volumes:
      - persistLogs:/var/log/files
      - sharedError:/var/errors

  # We should have 1 on EVERY node and configure it to 
  # collect logs from all containers in the node
  client:
    depends_on:
      - log_server
    build: ./logClient/
    restart: unless-stopped
    environment:
      - LOG_SERVER=log_server
    networks:
      - logging-net
    volumes:
      - nodeWideLogs:/var/log/files
      - sharedError:/var/errors
    deploy:
      mode: global
               
  

networks:
  logging-net:
    external: true
  
volumes:
  sharedError:
    driver: local
  persistLogs:
    driver: local
  nodeWideLogs:
    driver: local

here is how I try to communicate from the client:

python
import reuests
token = requests.get('http://log_server:4000/login', auth=('clientLog', 'Bbn4uazkVvfyHxhcbrhk2MeAE9yPh4r4nRfHWv'))

This is the error:

requests.exceptions.ConnectionError: HTTPConnectionPool(host='log_server', port=4000): Max retries exceeded with url: /login (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x7f0c2f470220>: Failed to establish a new connection: [Errno 111] Connection refused'))

What I do rung? They are both on the same network...

CodePudding user response：

It looks as if your log server is listening port 80, but you're trying to connect on port 4000.

Remember that port mappings don't affect container-to-container communication; they only affect on which host ports a service is exposed. Since you're connecting directly to the log_server container you should just be using port 80.

CodePudding user response：

When you do the port mapping in the log_server service you are opening a host port to have access to the mapped port inside the Docker container. From your machine(which is the host) you should be able to access the log server via localhost:4000.

Port mapping is about container/host, but log_server and client are two containers running on the same network. They have visibility of each other via docker internal DNS so it is correct to try to make a request to log_server, the problem is that you are trying to reach port 4000. Doing requests.get('http://log_server:80/login', or requests.get('http://log_server/login', should solve the issue.