4 images: ['waffleimage/centos7']
7 images: ['debian:8', 'debian:9', 'ubuntu:14.04', 'ubuntu:16.04', 'ubuntu:18.04']
10 images: ['waffleimage/debian8', 'waffleimage/debian9', 'waffleimage/ubuntu14.04', 'waffleimage/ubuntu16.04', 'waffleimage/ubuntu18.04']
13 images: ['centos:6', 'centos:7', 'oraclelinux:6', 'oraclelinux:7', 'scientificlinux/sl:6', 'scientificlinux/sl:7']
16 images: ['waffleimage/centos6', 'waffleimage/centos7', 'waffleimage/oraclelinux6', 'waffleimage/oraclelinux7', 'waffleimage/scientificlinux6', 'waffleimage/scientificlinux7']
19 images: ['redhat-5-x86_64', 'redhat-6-x86_64', 'redhat-7-x86_64', 'redhat-8-x86_64', 'centos-5-x86_64', 'centos-6-x86_64', 'centos-7-x86_64', 'oracle-5-x86_64', 'oracle-6-x86_64', 'oracle-7-x86_64', 'scientific-6-x86_64', 'scientific-7-x86_64', 'debian-8-x86_64', 'debian-9-x86_64', 'sles-11-x86_64', 'sles-12-x86_64', 'sles-15-x86_64', 'ubuntu-1404-x86_64', 'ubuntu-1604-x86_64', 'ubuntu-1804-x86_64', 'win-2008r2-x86_64', 'win-2012r2-x86_64', 'win-2016-x86_64', 'win-10-pro-x86_64']