At the moment, we are offering the following OSes as a standard:

■ CT(container)

centos-6
centos-7
debian-9.0
debian-8.0
ubuntu-18.04
ubuntu-16.04

■ VM(hypervisor/virtual machine) 

centos-6
centos-7
debian-9.0
debian-8.0
ubuntu-14.04
ubuntu-16.04
ubuntu-18.04
win2012r2-std(EN)
win2012r2-std(JP)
win2016-std(JP)
win2016-std(EN)
win2019-std(JP)
win2019-std(EN)