add caveats of RHEL 8

rhel8/index.md

@@ -19,12 +19,25 @@ It looks like it works already a lot out of the box, but no guarantee can be giv
 
 ### Major Known Issues
 
+- using a package snapshot tag (`yum_client::repo_tag` in hiera) different than `prod` will fail horribly
+
 ### Major Missing Features
 
 - default user home is local unless configured to be on AFS [PSILINUX-97](https://jira.psi.ch/browse/PSILINUX-97)
 - security patches are automatically installed [PSILINUX-98](https://jira.psi.ch/browse/PSILINUX-98)
 - minimal default installation, aka gem, git and postfix is not installed by default [PSILINUX-100](https://jira.psi.ch/browse/PSILINUX-100)
 
+### Caveats
+
+#### Workstation Installation Takes Long and Seams to Hang
+On the very first puppet run the command to install the GUI packages takes up to 10 minutes and it looks like it
+is hanging. Usually it is after the installation of `/etc/sssd/sssd.conf`. Just give it a bit time.
+
+#### Installing a Machine with YFS and an Old Package Snapshot Tag
+After the `pli-firstboot` script it stopps due to errors (installed yfs kernel module version does not fit running kernel). Still it manages to install everything fine.  
+So please restart the machine (so it loads the right kernel) and run `puppet agent` again to finally start and enable the `yfs-service`.
+
+
 ## Documenatation
 
 * [Installation (Alpha)](installation)