Glossary

Volume (Block Storage)

Persistent storage in bwCloud-OS that exists independently of a VM. Volumes can be attached to instances, resized, exported as images, or backed up via snapshots.

Image

Operating system image from which new instances are launched. bwCloud-OS provides various preconfigured images (e.g., Debian 12, Ubuntu 24.04); custom images can also be uploaded.

Instance / VM

Virtual machine running in a region. It receives CPU, RAM, network, and storage resources and behaves like a physical server.

Region

One of the four operational sites (Freiburg, Karlsruhe, Mannheim, Ulm). Each region is an independent OpenStack cluster with its own IP address logic.

Home Region

The region automatically assigned to a user during registration.

Flavor

Predefined resource profile for instances (number of vCPUs, RAM, local system disk). Examples: m1.small, m1.large.

Quota

Resource limit (vCPUs, RAM, volumes, etc.) per project. Increases can be requested via a support ticket.

Snapshot

Point-in-time copy of an instance or volume. Snapshots appear as images and can be downloaded or converted into new volumes/instances.

Floating IP

Publicly accessible IPv4 address that can be assigned to an instance as needed. This keeps the internal network topology unchanged.

Security Group

Set of firewall rules (inbound/outbound) assigned to an instance. By default, only SSH (port 22) is open; additional ports must be explicitly allowed.

External Storage (S3 / NFS)

Object storage or network drive for personal data, backups, or hard-to-reproduce results. Recommended for anything that is not temporary.

Project / Group Project

Administrative container for resources, users, and quotas. In a group project, multiple people share all instances, images, security groups, etc., equally.