My main machine at home has been upgraded from Fedora 26 to 27 since the day the 27 was released. Everything has been working great, except the ZFS file system. I’m a ZFS-believer and I store my important files on ZFS-based storage.
For a while there was no repository for Fedora 27 provided by zfsonlinux, until 6 days ago.
I have been using packages provided for Fedora 26 as work around solution. If you’ve been using the ZFS packages for Fedora 26, you can upgrade to the ones for Fedora 27 now.
Fedora 27 Package: http://download.zfsonlinux.org/fedora/zfs-release.fc27.noarch.rpm.