How to add Redis to a Docker Container?

Question

I have a Sinatra app that works fine in Docker:

# Image
FROM ruby:2.3.3
RUN apt-get update && \
    apt-get install -y net-tools


# Install app
ENV APP_HOME /app
ENV HOME /root
RUN mkdir $APP_HOME
WORKDIR $APP_HOME
COPY Gemfile* $APP_HOME/
RUN bundle install
COPY . $APP_HOME


# Configure App
ENV LANG en_US.UTF-8
ENV RACK_ENV production

EXPOSE 9292


# run the application
CMD ["bundle", "exec", "rackup"]

But when I try to add Redis:

# Redis
RUN         apt-get update && apt-get install -y redis-server
EXPOSE      6379
CMD         ["/usr/bin/redis-server"]

Redis does not seem to start.

So, what is a good way to add Redis to a Ruby (FROM ruby:2.3.3) Docker container?

score 5 · Accepted Answer · answered Feb 21 '17 at 19:15

5

Split this into two containers. You can use docker-compose to bring them up on a common network. E.g. here's a sample docker-compose.yml:

version: '2'

services:
  sinatraapp:
    image: sinatraapp:latest
    ports:
    - 9292:9292
  redis:
    image: redis:latest

The above can include more options for your environment, and assumes your image name is sinatraapp:latest, change that to the image you built. You'll also need to update your sinatra app to call redis by the hostname redis instead of localhost. Then run docker-compose up -d to start the two services.

answered Feb 21 '17 at 19:15

BMitch

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Yes, I saw that it is easier and better to do it this way. – B Seven Feb 21 '17 at 19:29
For the future searchers, the `redis` key won't work in this case. See http://stackoverflow.com/a/42380642/336920 – B Seven Feb 22 '17 at 17:42

score 2 · Answer 2 · edited May 23 '17 at 12:31

2

There can be only one CMD command in your Dockerfile. Moreover what you want to do is a little more complex than you might think.

P.S. The above are stackoverflow links.

edited May 23 '17 at 12:31

Community

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1

answered Feb 21 '17 at 19:08

Alkis Kalogeris

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It seems that the "Docker way" would be to have 2 containers. Simpler and easier. – B Seven Feb 21 '17 at 19:58
Yes that's the correct and easiest way if you don't have any serious complications. – Alkis Kalogeris Feb 21 '17 at 22:23

How to add Redis to a Docker Container?

2 Answers2