availability zone

An availability zone for AWS denotes a large subset of their cloud environment. Eucalyptus refines this definition to denote a subset of the cloud that shares a local area network. Each Eucalyptus zone has its own Cluster Controller and Storage Controller.


Amazon Web Services

bucket storage

A storage container that accepts objects via PUT and GET commands.


A virtual machine image splits the image into multiple image parts to facilitate ease of uploading. It also generates an XML manifest file containing metadata referencing the image, including image parts and kernel, which is used to assemble instances of the image.

Cloud Controller

The Cloud Controller (CLC) is the entry-point into the cloud for administrators, developers, project managers, and end-users. The CLC queries the node managers for information about resources, makes high-level scheduling decisions, and makes requests to the Cluster Controllers (CCs). As the interface to the management platform, the CLC is responsible for exposing and managing the underlying virtualized resources (servers, network, and storage).

Cluster Controller

The Cluster Controller (CC) generally executes on a machine that has network connectivity to both the machines running the Node Controller (NC) and to the machine running the CLC. CCs gather information about a set of node machines and schedules virtual machine (VM) execution on specific nodes. The CC also manages the virtual machine networks and participates in the enforcement of SLAs as directed by the CLC. All nodes associated with a single CC must be in the same broadcast domain (Ethernet).

dynamic block volume

A dynamic block volume is similar to a raw block storage device that can be used with VM instances. You can create, attach, detach, describe, bundle, and delete volumes. You can also create and delete snapshots of volumes and create new volumes from snapshots

elastic IP

Public IP addresses that you can reserve and dynamically associate with VM instances.


FastStart is an interactive installer that automatically deploys and configures a Eucalyptus cloud on your server. After install completes (usually in less than 30 minutes) you can immediately begin using your cloud with the default account, user and password.

hybrid cloud

Hybrid clouds combine one or more public clouds and one or more private clouds by technology that enables data and applications to migrate between them. A classic hybrid cloud definition also means using a shared API to enable hybrid operations.

Identity and Access Management

Identity and Access Management (IAM) enables you to securely control access to services and resources for your users. Using IAM, you can create and manage users and groups, and use permissions to allow and deny their access to resources.


instance type

An instance type defines what hardware the instance has, including the amount of memory, disk space, and CPU power.

JavaScript Object Notation

JSON is an open-source, text-based message format used for information exchange.


kernel/ramdisk pair

A ramdisk contains drivers that direct the kernel to launch appropriate system files when instantiating a virtual machine.

Management Console

The Management Console is a web-based interface that allows cloud users to provision and manage resources in a Eucalyptus cloud and on AWS; it also gives Eucalyptus cloud account administrators powerful tools to manage users, groups, roles, and policies.

Node Controller

The Node Controller (NC) executes on any machine that hosts VM instances. The NC controls VM activities, including the execution, inspection, and termination of VM instances. It also fetches and maintains a local cache of instance images, and it queries and controls the system software (host OS and the hypervisor) in response to queries and control requests from the CC. The NC is also responsible for the management of the virtual network endpoint.


storage abstraction

Refers to separating the API made available by a cloud to the end user from the details and specifics of the underlying physical storage infrastructure. For instance, Eucalyptus provides the EBS (Elastic Block Storage) abstraction, which provides a unified way to access block storage independent of the underlying physical storage system (e.g. Dell EqualLogic, NetApp, etc.)

Storage Controller

The Storage Controller (SC) provides functionality similar to the Amazon Elastic Block Storage (EBS) and is capable of interfacing with various storage systems (NFS, iSCSI, SAN devices, etc.). Elastic block storage exports storage volumes that can be attached by a VM and mounted or accessed as a raw block device. EBS volumes persist past VM termination and are commonly used to store persistent data. An EBS volume cannot be shared between VMs and can only be accessed within the same availability zone in which the VM is running. Users can create snapshots from EBS volumes. Snapshots are stored in Walrus and made available across availability zones. Eucalyptus with SAN support lets you use your enterprise-grade SAN devices to host EBS storage within a Eucalyptus cloud.

User-Facing Services

Eucalyptus' User-Facing Services (UFS) are the services offered by Eucalyptus for compute, storage, scaling, balancing, and more. These services reside at the front end of the cloud, sometimes co-located with the database, depending on your configuration.

virtual machine

A virtual machine (VM) is essentially an operational private computer that contains an operating system, applications, network accessibility, and disk drives.

virtual resources

A private cloud makes physical resources such as compute (CPU), network and storage in the data center available to the end user using virtualization technology, so that the user has complete control over their resources. These resources, i.e., compute, network and storage that are visible to the cloud user, are called virtual resources.


Walrus allows users to store persistent data, organized as buckets and objects. You can use Walrus to create, delete, and list buckets, or to put, get, and delete objects, or to set access control policies. Walrus is interface compatible with Amazon’s Simple Storage Service (S3), providing a mechanism for storing and accessing virtual machine images and user data. Note that Walrus access is global to the entire Eucalyptus cloud. This means that it can be accessed by end-users, whether the user is running a client from outside the cloud or from a virtual machine instance running inside the cloud.


A zone is a group of resources that contains a Cluster Controller (CC) and a Storage Controller (SC).