Packer w/ Docker

gistfile1.txt

sudo packer.io build centos-7.2-docker-base.json 
docker output will be in this color.

==> docker: Creating a temporary directory for sharing data...
==> docker: Pulling Docker image: centos:7.2.1511
    docker: Trying to pull repository docker.io/library/centos ...
    docker: 7.2.1511: Pulling from docker.io/library/centos
    docker: f19ed9d73b3e: Pulling fs layer
    docker: f19ed9d73b3e: Verifying Checksum
    docker: f19ed9d73b3e: Download complete
    docker: f19ed9d73b3e: Pull complete
    docker: f19ed9d73b3e: Pull complete
    docker: Digest: sha256:12c9336412cd76165d7e42906ab9a7234cecd7c4247ed92958ab4ad49644b531
    docker: Status: Downloaded newer image for docker.io/centos:7.2.1511
==> docker: Starting docker container...
    docker: Run command: docker run -v /root/.packer.d/tmp/packer-docker185099243:/packer-files -d -i -t centos:7.2.1511 /bin/bash
    docker: Container ID: 4296748eb80db54476de0851b329e070207af9c687faba1e17b1abd38f343a7e
==> docker: Committing the container
    docker: Image ID: sha256:3e139f18683cb4d9e7e506f0b7848ea702611ae328751407076f42029aa83877
==> docker: Killing the container: 4296748eb80db54476de0851b329e070207af9c687faba1e17b1abd38f343a7e
==> docker: Running post-processor: docker-tag
    docker (docker-tag): Tagging image: sha256:3e139f18683cb4d9e7e506f0b7848ea702611ae328751407076f42029aa83877
    docker (docker-tag): Repository: XXXX.dkr.ecr.us-west-2.amazonaws.com/cf-centos-base:latest
==> docker: Running post-processor: docker-push
    docker (docker-push): Logging in...
    docker (docker-push): WARNING: login credentials saved in /root/.docker/config.json
    docker (docker-push): Login Succeeded
    docker (docker-push): Pushing: XXXX.dkr.ecr.us-west-2.amazonaws.com/cf-centos-base
    docker (docker-push): The push refers to a repository [XXXX.dkr.ecr.us-west-2.amazonaws.com/cf-centos-base]
    docker (docker-push): 3cfebda1174f: Preparing
    docker (docker-push): dc44cf6f74b6: Preparing
    docker (docker-push): 3cfebda1174f: Pushed
    docker (docker-push): 3cfebda1174f: Pushed
    docker (docker-push): dc44cf6f74b6: Pushed
    docker (docker-push): dc44cf6f74b6: Pushed
    docker (docker-push): latest: digest: sha256:cc6758a35e39851af653a16f1533f9406a0e423f60091b9fdecda9ae978f70c4 size: 4393
    docker (docker-push): Logging out...
    docker (docker-push): Remove login credentials for https://XXXX.dkr.ecr.us-west-2.amazonaws.com
Build 'docker' finished.

==> Builds finished. The artifacts of successful builds are:
--> docker: Imported Docker image: sha256:3e139f18683cb4d9e7e506f0b7848ea702611ae328751407076f42029aa83877