nginx：Docker 容器无法启动

Question

In an attempt to Dockerize an application in four containers, the Nginx container is failing with an error. Specifically when I've run docker-compose up it displays:

nginx_1   | 2019/12/25 23:00:50 [emerg] 1#1: host not found in upstream "client:8080" in /etc/nginx/conf.d/default.conf:2
nginx_1   | nginx: [emerg] host not found in upstream "client:8080" in /etc/nginx/conf.d/default.conf:2

The docker-compose.yml and the nginx configuration and [ETA] the nginx container's Dockerfile.dev are included below. Things I've tried:

• In docker-compose.yml , setting the nginx container to

depends_on: 
  - client

• In default.conf , adding resolver 127.0.0.11; in the location / section of the server block

I'm somewhat unfamiliar with nginx and Docker. So I'd appreciate any help or insights.

---

docker-compose.yml

version: '3'
services:
  db:
    image: 'postgres:latest'
  nginx:
    build:
      dockerfile: Dockerfile.dev
      context: ../nginx-glen
    restart: always
    ports:
      - '3050:80'
  api:
    build:
      dockerfile: Dockerfile.dev
      context: ../cornish-glen
    volumes:
      - /app/node_modules
      - ../cornish-glen:/app
    depends_on:
      - db
    environment:
      - PGUSER=postgres
      - PGHOST=postgres
      - PGDATABASE=turnip_glen
      - PGPASSWORD=********
      - PGPORT=5432
  client:
    build:
      dockerfile: Dockerfile.dev
      context: .
    depends_on:
      - api
    volumes:
      - /app/node_modules
      - .:/app
    environment:
      - GRAPHQL_ORIGIN=http://api:3099

---

default.conf

upstream client {
  server client:8080;
}

upstream api {
  server api:3099;
}

server {
  listen 80;

  location / {
    proxy_pass http://client;
  }

  location /sockjs-node {
    proxy_pass http://client;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "Upgrade";
  }

  location /graphql {
    proxy_pass http://api;
  }
}

---

ETA nginx-glen/Dockerfile.dev

FROM nginx
COPY ./default.conf /etc/nginx/conf.d/default.conf

Answer 1

The answer lies in the webpack development server, which needs to be instructed to be flexible about the host in the following way:

// Only showing the devServer object here:
  devServer: {
    // These two lines are the relevant ones:
    // ---
    host: '0.0.0.0',
    disableHostCheck: true, // TODO: insecure, but probably fine for dev environment
    // ---
    contentBase: "./public",
    index: ''
  }

I'll also point out that the nginx container's [emerg] messages in the Docker logs do not seem to prevent the application from running.