Shiny server docker app runs locally but not when deployed to AWS Fargate - r

Question

I have a containerized R Shiny app that, when run locally with docker run --rm -p 3838:3838 [image] works as expected. The "landing" page appears when I go to localhost:3838 and all is good. However, when this container is deployed to AWS Fargate, things break down. The container appears to start and run, but there's no webpage being served on 3838 even though all ports are pointed to 3838 in Fargate.
I'm using dockerfile
FROM rocker/verse:3.5.1
LABEL Steven "email"
## Add shiny capabilities to container
RUN export ADD=shiny && bash /etc/cont-init.d/add
## Update and install
RUN tlmgr update --self
RUN tlmgr install beamer translator
## Add R packages
RUN R -e "install.packages(c('shiny', 'googleAuthR', 'dplyr', 'googleAnalyticsR', 'knitr', 'rmarkdown', 'jsonlite', 'scales', 'ggplot2', 'reshape2', 'Cairo', 'tinytex'), repos = 'https://cran.rstudio.com/')"
#Copy app dir and them dirs to their respective locations
COPY app /srv/shiny-server/ga-reporter
COPY app/report/themes/SwCustom /opt/TinyTeX/texmf-dist/tex/latex/beamer/
#Force texlive to find my custom beamer thems
RUN texhash
EXPOSE 3838
## Add shiny-server information
COPY shiny-server.sh /usr/bin/shiny-server.sh
COPY shiny-customized.config /etc/shiny-server/shiny-server.conf
## Add dos2unix to eliminate Win-style line-endings and run
RUN apt-get update && apt-get install -y dos2unix
RUN dos2unix /usr/bin/shiny-server.sh && apt-get --purge remove -y dos2unix && rm -rf /var/lib/apt/lists/*
RUN ["chmod", "+x", "/usr/bin/shiny-server.sh"]
CMD ["/usr/bin/shiny-server.sh"]
and shiny-server.conf
# Instruct Shiny Server to run applications as the user "shiny"
run_as shiny;
# Define a server that listens on port 3838
server {
listen 3838;
# Define a location at the base URL
location / {
# Host the directory of Shiny Apps stored in this directory
app_dir /srv/shiny-server/ga-reporter;
# Log all Shiny output to files in this directory
log_dir /var/log/shiny-server;
# When a user visits the base URL rather than a particular application,
# an index of the applications available in this directory will be shown.
directory_index on;
}
}
with shiny-server.sh
#!/bin/sh
# ShinyServer: Make sure the directory for individual app logs exists
mkdir -p /var/log/shiny-server
chown -R shiny.shiny /var/log/shiny-server
# RUN ShinyServer
exec shiny-server >> /var/log/shiny-server.log 2>&1
I have edited the .conf file to display the app (i.e., location /) in /srv/shiny-server/ga-reporter which is also where I've copied the app_dir in the Dockerfile. Shiny is listening on port 3838 and should serve the page there. Again, this happens locally but not when deployed to AWS Fargate. I've tried logging Shiny logs to stdout by using the first answer provided here but have had no luck seeing any errors generated. Server "health checking" is only offered in the "pro" version so I can't check to see if the server is actually running.
On AWS, the container starts and appears to function normally (i.e., the "normal" start up logs appear):
but there is simply no page displayed at the location I expect it to be served.
I found another Shiny app that is on dockerhub running under the same configuration as the Fargate cluster but have had no luck trying to implement anything in the shiny-server.conf or the shiny-server.sh files located there.
What am I missing? Everything on Fargate is pointed to listening on 3838; there must be something I'm missing in the .conf file for this to be failing when deployed.
EDIT
I can't bash in to the running container on Fargate because I don't have access to the server on which docker is running.
Fargate has a UI that accepts host and container ports:
EDIT 2 (2018-08-27)
The engineer that was deploying this has been able to resolve the issue:
"it was the port change, I forgot to can the port on the ALB’s security group, I only updated the cluster’s inbound rules
so the cluster was allowing connections, but the ALB security group wasn’t letting it out"