ERR_CONNECTION_REFUSED with docker container
I am new to Docker and am trying to make a demo Rails application. I made a docker file that looks like this:
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"]
Then I built it (no error):
docker build -t demo .
And then run it (also no errors):
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
When I run the command docker ps
in a separate terminal to determine ports, I get:
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
However, when I try to connect to it with http://localhost:32772
either http://192.168.99.100:32772
Chrome or curl, I get a "Connection failed" message.
When I run the application outside of docker on my local machine using a command bundle exec rails server
, it works fine. Please note that I am using Docker Toolbox on my Win7 machine.
What could I be doing wrong?
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A combination of the above tricks -
I had to use http://<VM IP ADDRESS>:32772
(localhost: 32772 DOES NOT WORK) AND I had to fix my open port to match TCP listening port 9292.
I still don't understand why the default TCP listening port was 9292 instead of 3000, but I'll cover that separately.
Thanks for the help!
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I spent a couple of hours on this and this thread was really helpful. What I am doing right now is accessing these services via the vm ip address.
You can get your vm address:
docker-machine ls
then try to access your service using port 37772 mapped to host, something like this:
http://<VM IP ADDRESS>:32772
Hope it helps.
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