Host Operating System (Host) : ‘Host OS’ or ‘Host’ is commonly referred to the Operating System installed on your hardware (Laptop/Desktop) and hosts the virtual machines. In short, the machine on which your Virtual Box is installed. Guest Operating System (Guest):     ‘Guest OS’ or ‘Guest’ is commonly referred to the Operating System installed on your Virtual Box Virtual Machine and is an Virtual Instance independent of the host OS. Node : Node in this context is referring specifically to Servers. Each OpenStack server is a node. Control Node:     Control Node hosts the Database, Keystone (Middleware) and the servers for the scope of the current OpenStack deployment. It is kind of like the ‘brains behind OpenStack’ and drives the services like authentication, database etc. Compute Node:     Compute Node has the required Hypervisor (Qemu/KVM), and is your Virtual Machine Host. Network Node:     Network Node provides Network as a Service and is responsible for providing virtual networks for OpenStack. Using OpenSSH Once you are done with setting up of network interfaces file, you may switch over to SSH session by remote login into the required server node (Control, Network, Compute) by using OpenSSH Client. Open Terminal on your Host machine, and type in the following command $ssh-keygen -t rsa You should see similar output  : Generating public/private rsa key pair. Enter file in which to save the key (/u/kim/.ssh/id_rsa): [RETURN] Enter passphrase (empty for no passphrase): <can be left empty> Enter same passphrase again: <can be left empty> Your identification has been saved in /home/user/.ssh/id_rsa. Your public key has been saved in /home/user/.ssh/id_rsa.pub. The key fingerprint is:   b7:18:ad:3b:0b:50:5c:e1:da:2d:6f:5b:65:82:94:c5 xyz@example