Fedora Atomic Host installations use the rpm-ostree deployment method, where packages are assembled on the Fedora release engineering side and delivered as atomic units, rather than the yum/DNF method of client side assembly. Consequently, they do not use the DNF system upgrade mechanism which is used to upgrade between Fedora releases for other Fedora installations. Instead, use the procedure described here.
- You must currently "setenforce 0" before upgrading. https://bugzilla.redhat.com/show_bug.cgi?id=1309075
Let's assume you're upgrading from Fedora 29 to 30. First, you'll need to remove the remote for the previous major version:
sudo ostree remote delete fedora-atomic
Next, add a remote for the new major version:
sudo ostree remote add fedora-atomic --set=gpg-verify=false https://dl.fedoraproject.org/pub/fedora/linux/atomic/30
Then, rebase to it:
sudo rpm-ostree rebase fedora-atomic:fedora-atomic/30/x86_64/docker-host
Like any other rpm-ostree update, this is staged for the next reboot, so to finally apply the update:
sudo systemctl reboot
That should be all!