It is available in ppa:cyberhull/cybercache and can be installed using Ubuntu’s package manager, apt. You can choose between Community and Enterprise editions, and the server and the Magento extension are now installable separately. The Magento extension’s PHP code can be installed by requiring cyberhull/magento2-module-cybercache in Composer. It is also included in the cybercache-extension Ubuntu packages for your convenience.
Complete source code (GPL v2) is available at https://github.com/cyberhull/cybercache-cluster.