Minimum of 4 GB memory (6 GB or more recommended)
CentOS(RHEL) 6 (x86_64) and above
Ubuntu 14 (x86_64) and above
Debian 7 (x86_64) and above
openSUSE 12 (x86_64) and above
For detailed instructions on docker installation, please refer to CubeBackup Installation using Docker.