A group of resources that contains a CC, an SC and, optionally, a VMware Broker.

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 availability zone has its own cluster controller and storage controller.

Amazon Web Services

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.

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 [SM1] 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). You can access the CLC through Amazon’s Elastic Compute Cloud (EC2) and through a web-based Eucalyptus Administrator Console.

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[SM3] as directed by the CLC. All nodes associated with a single CC must be in the same broadcast domain (Ethernet).

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

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.

The Storage Controller (SC) provides functionality similar to the [5] 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.

VMware Broker (Broker or VB) is an optional Eucalyptus component activated only in versions of Eucalyptus with VMware support. VMware Broker enables Eucalyptus to deploy VMs on VMware infrastructure elements and mediates all interactions between the Cluster Controller (CC) and VMware hypervisors (ESX/ESXi) either directly or through VMware vCenter.

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.