The links used in this course might sometimes get expired or be removed by the people managing those links. In case a download Link for a virtual machine does not work, there are two options for you. The first option is a Docker, for example, an Ubuntu Docker, if you require a lightweight machine. The other option is creating a QEMU VM. It is a custom virtual machine you can create on your GNS3. That way, you can have ANY virtual machine with ANY version you want on your GNS3. We have a lecture in this course called "Headquarter - Create a custom VM for the openSUSE Linux Server cluster" where we show how to create such a manual VM in GNS3. There we show how to create the latest version of OpenSUSE, but you can follow the same steps in that lecture and create your own version of any VM like the Ubuntu Server on your GNS3 platform.