Cockpit is a management system for Linux servers. It is typically accessed on port 9090 using either the server IP address or DNS name.

apt install cockpit cockpit-bridge cockpit-dashboard cockpit-docker cockpit-machines cockpit-networkmanager cockpit-packagekit cockpit-storaged cockpit-system cockpit-ws

You need to create one file containing the certificate, the intermediate certificate and the certificate key. The easiest is to cat the files together.

cat server.crt > ssl.cert
cat myCA.pem >> ssl.cert
cat server.key >> ssl.cert

Next copy the cert to /etc/cockpit/ws-certs.d and restart cockpit.

systemctl restart cockpit

You can check which certificate is used by cockpit with

remotectl certificate

To get a serial console to a vm you need to enable getty to listen to the serial port.

systemctl enable --now serial-getty@ttyS0