This repo provides an example of how to use packer to build a generic nginx server from either a CentOS or Ubuntu container image. The basic workflow is as follows:

1. Packer pulls the desired container image
2. It uses a shell provisioner for the Ubuntu image to ensure that python is installed. CentOS bundles python since there are a few dependencies on python built into the distribution.
3. Runs an Ansible playbook against the container to configure the system. The ansible-remote method is utilized to prevent any remnants of Ansible from being installed on the container.
4. Tags and pushes the container to a Docker Hub account

There are a few prerequisites needed to make it all go:

1. Packer - https://packer.io/docs/install/index.html
2. Ansible 2.7+ - https://docs.ansible.com/ansible/latest/installation_guide/intro_installation.html
3. Docker - https://docs.docker.com/install/
4. A Docker Hub account - https://hub.docker.com/signup

The packer template supports a few user supplied variables:

• container_image (required) - should be either centos or ubuntu to pull the corresponding image from Docker Hub
• container_tag (optional) - defaults to latest, a more fun value like git rev-parse --short HEAD could be used to facilitate promotions
• docker_hub_user (required) - the Docker Hub user account to push containers to

The image can be built and shipped via the following command:

packer build -var container_image=<centos|ubuntu> -var docker_hub_user=<docker_hub_username> template.json

The build process assumes that the docker daemon is already logged in to the Docker Hub account. This process is separated from the build step so that:

1. Credentials can be isolated from the stack repository
2. Credentials could be passed in to the build process in a pipeline and handled in a more secure fashion

Once the container is built, it could be run as shown below. This repositry includes a sample html folder containing an index.html file for demonstration purposes.

docker run --name nginx-test -v <path_to_repo_checkout>/html:/html -p 8888:80 -d <docker_hub_username>/<centos|ubuntu>-nginx:latest

Once the container is running it can be viewed in a web browser at http://127.0.0.1:8888/.

The nginx daemon writes its logs to its stderr stream so that they can be accessed via the docker daemon or the container platform's designated logging system.