How to run command inside Docker container - amazon-web-services

Question

I'm new to Docker and I'm trying to understand the following setup.
I want to debug my docker container to see if it is receiving AWS credentials when running as a task in Fargate. It is suggested that I run the command:
curl 169.254.170.2$AWS_CONTAINER_CREDENTIALS_RELATIVE_URI
But I'm not sure how to do so.
The setup uses Gitlab CI to build and push the docker container to AWS ECR.
Here is the dockerfile:
FROM rocker/tidyverse:3.6.3
RUN apt-get update && \
apt-get install -y openjdk-11-jdk && \
apt-get install -y liblzma-dev && \
apt-get install -y libbz2-dev && \
apt-get install -y libnetcdf-dev
COPY ./packrat/packrat.lock /home/project/packrat/
COPY initiate.R /home/project/
COPY hello.Rmd /home/project/
RUN install2.r packrat
RUN which nc-config
RUN Rscript -e 'packrat::restore(project = "/home/project/")'
RUN echo '.libPaths("/home/project/packrat/lib/x86_64-pc-linux-gnu/3.6.3")' >> /usr/local/lib/R/etc/Rprofile.site
WORKDIR /home/project/
CMD Rscript initiate.R
Here is the gitlab-ci.yml file:
image: docker:stable
variables:
ECR_PATH: XXXXX.dkr.ecr.eu-west-2.amazonaws.com/
DOCKER_DRIVER: overlay2
DOCKER_TLS_CERTDIR: ""
services:
- docker:dind
stages:
- build
- deploy
before_script:
- docker info
- apk add --no-cache curl jq py-pip
- pip install awscli
- chmod +x ./build_and_push.sh
build-rmarkdown-task:
stage: build
script:
- export REPO_NAME=edelta/rmarkdown_report
- export BUILD_DIR=rmarkdown_report
- export REPOSITORY_URL=$ECR_PATH$REPO_NAME
- ./build_and_push.sh
when: manual
Here is the build and push script:
#!/bin/sh
$(aws ecr get-login --no-include-email --region eu-west-2)
docker pull $REPOSITORY_URL || true
docker build --cache-from $REPOSITORY_URL -t $REPOSITORY_URL ./$BUILD_DIR/
docker push $REPOSITORY_URL
I'd like to run this command on my docker container:
curl 169.254.170.2$AWS_CONTAINER_CREDENTIALS_RELATIVE_URI
How I run this command on container startup in fargate?

Answer 1

For running a command inside docker container you need to be inside the docker container.
Step 1: Find the container ID / Container Name that you want to debug
docker ps A list of containers will be displayed, pick one of them
Step 2 run following command
docker exec -it <containerName/ConatinerId> bash and then enter wait for few seconds and you will be inside the docker container with interactive mode Bash
for more info read https://docs.docker.com/engine/reference/commandline/exec/

Answer 2

Short answer, just replace the CMD
CMD ["sh", "-c", " curl 169.254.170.2$AWS_CONTAINER_CREDENTIALS_RELATIVE_UR && Rscript initiate.R"]
Long answer, You need to replace the CMD of the DockerFile, as currently running only Rscript.
you have two option add entrypoint or change CMD, for CMD check above
create entrypoint.sh and run run only when you want to debug.
#!/bin/sh
if [ "${IS_DEBUG}" == true ];then
echo "Container running in debug mode"
curl 169.254.170.2$AWS_CONTAINER_CREDENTIALS_RELATIVE_URI
# uncomment below section if you still want to execute R script.
# exec "$#"
else
exec "$#"
fi
Changes that will required on Dockerfile side
WORKDIR /home/project/
ENV IS_DEBUG=true
COPY entrypoint.sh /entrypoint.sh
RUN chmod +x /entrypoint.sh
entrypoint ["/entrypoint.sh"]
CMD Rscript initiate.R