Docker nginx 502 bad gateway for GET/Post requests but not websocket

Question

There have been various similar cases here on stackoverflow but they're pretty much all refer to incorrect ports or using localhost as the IP instead of the docker-machine ip.

The vue.js app connects perfectly fine to the websocket and works. However, the GET requests to 192.168.99.100:8080/meows and other endpoints all hit the nginx 502 bad gateway. Manually accessing the endpoints (instead of vue.js) also hit 502 bad gateway.

The ip's are properly set. Ports are the same everywhere :8080. endpoints have the correct http verband all have an nginx upstream pointing at the server location /..{}. Yet no problems connecting to the network, all data passing through no problem.

EDIT: Im running windows 7 with the docker-toolbox because my windows version doesnt have the whole virtualization thing. No further configuration after installation has been done.

The architecture is the following:

docker-compose

version: "3.6"

services:
  meow:
    build: "."
    command: "meow-service"
    depends_on:
      - "postgres"
      - "nats"
    environment:
      POSTGRES_DB: "meower"
      POSTGRES_USER: "meower"
      POSTGRES_PASSWORD: "123456"
      NATS_ADDRESS: "nats:4222"
  query:
    build: "."
    command: "query-service"
    depends_on:
      - "postgres"
      - "nats"
    environment:
      POSTGRES_DB: "meower"
      POSTGRES_USER: "meower"
      POSTGRES_PASSWORD: "123456"
      NATS_ADDRESS: "nats:4222"
      ELASTICSEARCH_ADDRESS: "elasticsearch:9200"
  pusher:
    build: "."
    command: "pusher-service"
    depends_on:
      - "nats"
    environment:
      NATS_ADDRESS: "nats:4222"
  postgres:
    build: "./postgres"
    restart: "always"
    environment:
      POSTGRES_DB: "meower"
      POSTGRES_USER: "meower"
      POSTGRES_PASSWORD: "123456"
  nats:
    image: "nats-streaming:0.9.2"
    restart: "always"
  elasticsearch:
    image: 'docker.elastic.co/elasticsearch/elasticsearch:6.2.3'
  nginx:
    build: "./nginx"
    ports:
      - "8080:80"
    depends_on:
      - "meow"
      - "query"
      - "pusher"

nginx.conf:

user nginx;
worker_processes 1;

events {
  worker_connections 1024;
}

http {
  upstream meows_POST {
    server meow:8080;
  }

  upstream meows_GET {
    server query:8080;
  }

  upstream search_GET {
    server query:8080;
  }

  upstream pusher {
    server pusher:8080;
  }

  server {
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    add_header Access-Control-Allow-Origin *;

    location /meows {
      limit_except GET POST OPTIONS {
        deny all;
      }
      proxy_pass http://meows_$request_method;
    }

    location /search {
      limit_except GET OPTIONS {
        deny all;
      }
      proxy_pass http://search_GET;
    }

    location /pusher {
      proxy_set_header Upgrade $http_upgrade;
      proxy_set_header Connection "upgrade";
      proxy_pass http://pusher;
    }
  }
}

And to show that the go application also uses the correct ports, the following is the port listening for

func newRouter() (router *mux.Router) {
    router = mux.NewRouter()
    router.HandleFunc("/meows", listMeowsHandler).
        Methods("GET")
    router.HandleFunc("/search", searchMeowsHandler).
        Methods("GET")
    return
}

router := newRouter()
if err := http.ListenAndServe(":8080", router); err != nil {
    log.Fatal(err)
}

Answer 1

Instead of:

ports:
  - "8080"

in every docker-compose service, try:

ports:
  // I assume your containers operate on 8080 port
  - "8080:8080"

By specifying just 8080 you assign container's port 8080 to your host's random port. I believe you don't want that. You can verify that with docker-compose ps.

Also why do you change the default port everywhere to 8080? With Docker it's not necessary, you can simply map the port to a different port on the host side, eg:

ports:
    - "8080:80"

Remember that containers talk to each other using their ports and those ports don't need to be published. You only publish ports you want to access "from the outside world".

Answer 2

Removed all

  ports:
  - "8080"

properties from all services in the ngix.conf as was proposed.

The underlying problem however was the elasticsearch docker image. Using docker ps -a i could see that after a minute it would exit 78. Using docker-compose logs elasticsearch the error was max virtual memory areas vm.max_map_count px[ is too low, increase to at least [x]. Using belows command the host machine allocated more memory for the containers and everything was solved.

docker-machine ssh
sudo sysctl -w vm.max_map_count=262144