The presence of swap is causing trouble on kubernetes hosts, and it's not clear that it's doing anyone else any good. Let's just get rid of it.
For the record, this is what we do for the new k8s in Toolforge: profile::toolforge::k8s::kubeadm::preflight_checks in file modules/profile/manifests/toolforge/k8s/kubeadm/preflight_checks.pp.
The default Buster base image now has now swap partition. Future Stretch images will also not have one but I haven't installed a new Stretch build yet -- that can probably wait until we have other reasons to build a new one.