Docker 容器的 ERR_CONNECTION_REFUSED

Question

我是 Docker 的新手，正在尝试制作一个演示 Rails 应用程序。我制作了一个如下所示的 dockerfile：

FROM ruby:2.2 

# Install apt based dependencies required to run Rails as 
# well as RubyGems. As the Ruby image itself is based on a 
# Debian image, we use apt-get to install those.
RUN apt-get update && apt-get install -y \ 
  build-essential \ 
  nodejs

# Configure the main working directory. This is the base 
# directory used in any further RUN, COPY, and ENTRYPOINT 
# commands.
RUN mkdir -p /app 
WORKDIR /app

# Copy the Gemfile as well as the Gemfile.lock and install 
# the RubyGems. This is a separate step so the dependencies 
# will be cached unless changes to one of those two files 
# are made.
COPY Gemfile Gemfile.lock ./ 
RUN gem install bundler && bundle install --jobs 20 --retry 5

# Copy the main application.
COPY . ./

# Expose port 3000 to the Docker host, so we can access it 
# from the outside.
EXPOSE 3000

# The main command to run when the container starts. Also 
# tell the Rails dev server to bind to all interfaces by 
# default.
CMD ["bundle", "exec", "rails", "server", "-b", "0.0.0.0"]

然后我构建了它（没有错误）：

docker build -t demo . 

然后运行它（也没有错误）：

docker run -itP demo
=> Booting Puma
=> Rails 5.1.1 application starting in development on http://0.0.0.0:3000
=> Run `rails server -h` for more startup options
Puma starting in single mode...
* Version 3.8.2 (ruby 2.2.7-p470), codename: Sassy Salamander
* Min threads: 5, max threads: 5
* Environment: development
* Listening on tcp://0.0.0.0:9292
Use Ctrl-C to stop

当我docker ps在单独的终端中运行命令以确定端口时，我得到：

CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                     NAMES
55e8224f7c15        demo                "bundle exec rails..."   About an hour ago   Up About an hour    0.0.0.0:32772->3000/tcp   ecstatic_bohr

然而，当我尝试在可以连接到它http://localhost:32772或http://192.168.99.100:32772使用Chrome或通过curl命令，我收到一个“连接被拒绝”。

当我通过bundle exec rails server命令在本地机器上的 docker 之外运行应用程序时，它工作正常。请注意，我在 Win7 机器上使用 Docker Toolbox

我可能做错了什么？

Answer 1

上述技巧的结合奏效了——

我必须使用http://<VM IP ADDRESS>:32772（localhost:32772 不起作用），并且我必须修复暴露的端口以匹配 TCP 侦听端口 9292。

我仍然不明白为什么 TCP 监听端口默认为 9292 而不是 3000，但我会单独研究一下。

感谢您的帮助！