How to run a docker image on Digital Ocean droplet?

Question

I have a Ubuntu based droplet on Digital Ocean with Docker installed, and where I uploaded my docker image.tar file from my desktop. I uploaded this image.tar file into /home/newuser/app directory. Next, I loaded the image.tar using following command:

sudo docker load -i image.tar

The image has been loaded. I checked.

When I run these following lines, I can't see my image app on public IP connected to my droplet instance:

sudo docker run image

or

sudo docker run -p 80:80 image

How do you guys go about this?

Here is the dockerfile:

FROM r-base:3.5.0

# Install Ubuntu packages
RUN apt-get update && apt-get install -y \
    sudo \
    gdebi-core \
    pandoc \
    pandoc-citeproc \
    libcurl4-gnutls-dev \
    libcairo2-dev/unstable \
    libxt-dev \
    libssl-dev 


# Add shiny user
RUN groupadd  shiny \
&& useradd --gid shiny --shell /bin/bash --create-home shiny



# Download and install ShinyServer
RUN wget --no-verbose https://download3.rstudio.org/ubuntu-14.04/x86_64/shiny-server-1.5.7.907-amd64.deb && \
    gdebi shiny-server-1.5.7.907-amd64.deb


# Install R packages that are required
RUN R -e "install.packages(c('Benchmarking', 'plotly', 'DT'), repos='http://cran.rstudio.com/')"
RUN R -e "install.packages('shiny', repos='https://cloud.r-project.org/')"

# Copy configuration files into the Docker image
COPY shiny-server.conf  /etc/shiny-server/shiny-server.conf
COPY /app /srv/shiny-server/

# Make the ShinyApp available at port 80
EXPOSE 80

# Copy further configuration files into the Docker image
COPY shiny-server.sh /usr/bin/shiny-server.sh

CMD ["/usr/bin/shiny-server.sh"]

The code for shiny-server.conf :

# Define the user we should use when spawning R Shiny processes
run_as shiny;

# Define a top-level server which will listen on a port
server {
  # Instruct this server to listen on port 80. The app at dokku-alt need expose PORT 80, or 500 e etc. See the docs
  listen 80;

  # Define the location available at the base URL
  location / {

    # Run this location in 'site_dir' mode, which hosts the entire directory
    # tree at '/srv/shiny-server'
    site_dir /srv/shiny-server;

    # Define where we should put the log files for this location
    log_dir /var/log/shiny-server;

    # Should we list the contents of a (non-Shiny-App) directory when the user 
    # visits the corresponding URL?
    directory_index on;
  }
}

And code for shiny-server.sh :

# Make sure the directory for individual app logs exists
mkdir -p /var/log/shiny-server
chown shiny.shiny /var/log/shiny-server

exec shiny-server >> /var/log/shiny-server.log 2>&1

sudo docker run -p 80:80 image should do it if port 80 is internally exposed in the container. Unless you have a firewall running in the droplet. — Robert Moskal
how do you check if port 80 is exposed in the container? if this is something related to Dockerfile, then yeah port 80 is explicitly declared in that document. I have similar issue when I run the image from local docker on my desktop, meaning the image won't load on localhost. — ZiaW
I have added the dockerfile to my question. see if there are any anomalies specifically related to image loading on host. thanks. — ZiaW

Robert Moskal Robert Moskal · Accepted Answer · 2018-08-27T14:18:53

There's really no need to EXPOSE port 80 in the docker file when you run the container with -p 80:80, except maybe as a hint to others: https://forums.docker.com/t/what-is-the-use-of-expose-in-docker-file/37726/2

You should probably post your shiny-server.conf, but I betcha that you either specified no port (in which case shiny-server starts on port 3838) or a port other than 80. Make sure you modify this line in the config file:

listen 3838

How to run a docker image on Digital Ocean droplet?

1 Answers