i have enabled host only adapter on my virtualmachine. After logged into server, then running ifconfig to check the interface, i cant see it. it turns out the interface is still down, so i need to bring up first:
sudo ifconfig enp0s8 up
after that, the interface is done up, but there is no IP address given on that (DHCP). To solve it, you need to add enp0s8 and mark it as DHCP in /etc/netplan/50-cloud-init.yaml
See this video for detail