Engineer in this your IT: Traffic analysis inside docker

If you haven't any application logging facilities alongside the containers, you can use old good tcpdump:

1.
2├── ./app1
3│   ├── ./app1/app1.py
4│   ├── ./app1/Dockerfile
5│   └── ./app1/requirements.txt
6├── ./app2
7│   ├── ./app2/app2.py
8│   ├── ./app2/Dockerfile
9│   └── ./app2/requirements.txt
10├── ./docker-compose.yaml
11├── ./nginx
12│   ├── ./nginx/Dockerfile
13│   └── ./nginx/nginx.conf
14└── ./traffic
15    └── ./traffic/tcpdump.pcap

app1/app1.py

1 
2from flask import request, Flask
3import json
4
5app1 = Flask(__name__)
6@app1.route('/')
7
8def hello_world():  return 'This is App1 :) '
9
10if __name__ == '__main__':  app1.run(debug=True, host='0.0.0.0')

app1/requirements.txt

1Flask==1.1.1

app1/Dockerfile

1FROM python:3
2COPY ./requirements.txt /requirements.txt
3WORKDIR /
4RUN pip install -r requirements.txt
5COPY . /
6ENTRYPOINT [ "python3" ]
7CMD [ "app1.py" ]

app2/app2.py

1app2/app2.py 
2from flask import request, Flask
3import json
4
5app2 = Flask(__name__)
6@app2.route('/')
7
8def hello_world():  return 'This is App2 :) '
9
10if __name__ == '__main__':  app2.run(debug=True, host='0.0.0.0')

app2/requirements.txt

1Flask==1.1.1

app2/Dockerfile

1FROM python:3
2COPY ./requirements.txt /requirements.txt
3WORKDIR /
4RUN pip install -r requirements.txt
5COPY . /
6ENTRYPOINT [ "python3" ]
7CMD [ "app2.py" ]

nginx/Dockerfile

1FROM nginx
2RUN rm /etc/nginx/conf.d/default.conf
3COPY nginx.conf /etc/nginx/conf.d/default.conf

nginx/nginx.conf

1upstream loadbalancer {
2server 172.17.0.1:5001 weight=5;
3server 172.17.0.1:5002 weight=5;
4}
5server {
6location / {
7proxy_pass http://loadbalancer;
8}}

docker-compose.yaml

1version: "3"
2networks:
3  tools-network:
4    driver: bridge
5services:
6  app1:
7    build: ./app1
8    ports:
9      - "5001:5000"
10    networks:
11      - tools-network
12  app2:
13    build: ./app2
14    ports:
15      - "5002:5000"
16    networks:
17      - tools-network
18  nginx:
19    build: ./nginx
20    ports:
21      - "8080:80"
22    depends_on:
23      - app1
24      - app2
25    networks:
26      - tools-network
27  tcpdump:
28     image: kaazing/tcpdump
29     network_mode: "host"
30     volumes:
31       - ./traffic:/tcpdump