Hi,
I added a new host to my cluster which went fine and no errors. The OS is debian 9 stable.
roxmox-ve: 5.3-1 (running kernel: 4.15.18-9-pve)
pve-manager: 5.3-5 (running version: 5.3-5/97ae681d)
pve-kernel-4.15: 5.2-12
pve-kernel-4.15.18-9-pve: 4.15.18-30
corosync: 2.4.4-pve1
criu...