Create build images

Introduction

Bigtop uses docker based images as build environment for its components.

It provideds support for following OS-platforms as of 2018-6-26:

CentOS-7(x86), Debian-9(x86), Fedora-26(x86, ppc64le), OpenSUSE-42.3(x86), Ubuntu-16.04(x86,ppc64le,aarch64)

The hierarchy of these images is:

Pre-requesties

Docker
```
sudo apt-get install -y docker.io
```

Bigtop/puppet-{OS} images

To build bigtop/puppet images, say, ubuntu-16.04-aarch64:

cd <BIGTOP_SRC_TOP>
./gradlew -POS=ubuntu-16.04 -Pprefix=trunk bigtop-puppet

This will create bigtop/puppet:trunk-ubuntu-16.04-aarch64 image.

$ docker images
REPOSITORY            TAG                          IMAGE ID            CREATED             SIZE
bigtop/puppet         trunk-ubuntu-16.04-aarch64   d540810efa71        4 days ago          305.9 MB
aarch64/ubuntu        16.04                        a7d1ddc47ced        10 weeks ago        109.7 MB

Bigtop/slaves-{OS} images

cd <BIGTOP_SRC_TOP>
./gradlew -POS=ubuntu-16.04 -Pprefix=trunk bigtop-slaves

This will create bigtop/slaves:trunk-ubuntu-16.04-aarch64 image.

$ docker images
REPOSITORY            TAG                          IMAGE ID            CREATED             SIZE
bigtop/slaves         trunk-ubuntu-16.04-aarch64   5b4c77dc374f        2 hours ago         2.861 GB
bigtop/puppet         trunk-ubuntu-16.04-aarch64   d540810efa71        4 days ago          305.9 MB
aarch64/ubuntu        16.04                        a7d1ddc47ced        10 weeks ago        109.7 MB