Comment 8 for bug 1540476

@Igor, Roman, first of all we already use mos snapshot while building ISO https://product-ci.infra.mirantis.net/job/9.0.all/93/artifact/artifacts/mos_centos_mirror_id.txt and https://product-ci.infra.mirantis.net/job/9.0.all/93/artifact/artifacts/mos_ubuntu_mirror_id.txt. Second point these original failures were related to ubuntu bootstrap, which doesn't support snapshots.
So if you you avoid such failures, please make sure that ubuntu bootstrap can work with snapshots.