Openstack词汇表查询

Openstack词汇表查询

OpenStack Glossary

Contents

Glossary

These terms and definitions offer a basic glossary for words and phrases related to OpenStack. You can add to this glossary by forking the openstack-manuals repository on github.com and updating the source files through the OpenStack contribution process.

 Glossary

A

Active Directory

Authentication and identity service by Microsoft, based on LDAP, currently not supported in OpenStack.

Absolute Limit

Impassable limits for Nova virtual machines, settings include total RAM size, maximum number of vCPUs, and maximum disk size.

Access Key

Alternative term for an Amazon EC2 Access Key.

Account

The Swift context of an account, not to be confused with a user account from an identity service (Active Directory, /etc/passwd, OpenLDAP, Keystone, etc).

Accounting

Nova provides accounting information via the event notification and system usage data facilities.

Account Auditor

Checks for missing replicas, incorrect, and corrupted objects in a specified Swift account by executing queries against the backend sqlite database.

Account Database

A sqlite database that contains Swift accounts and related metadata and is accessed by the accounts server.

Account Reaper

A Swift worker that scans for and deletes account databases that have been marked for deletion on an account server.

Account Server

Provides the listing of Containers in Swift, stores it's information in the account database.

Account Service

Component of Swift that provides account services such as list, create, modify, and audit. Not to be confused with Keystone, OpenLDAP, or similar user account services.

Address Pool

A group of fixed and/or floating IP addresses that are assigned to a Nova project and can in turn be used by or assigned to the project's VM instances.

Admin API

A subset of API calls that are accessable to only authorized administrators and are generally not accessable to end users or the public internet, can exist as a separate service (Keystone) or can be a subset of another API (Nova).

Admin Server

In the context of Keystone this is the worker process that that provides access to the admin API.

Advanced RISC Machine (ARM)

Lower power consumption CPU often found in mobile and embedded devices, supported by OpenStack.

Alert

Nova can send alerts using it's notification system which includes a facility to create custom notification drivers. Alerts can be sent to and displayed on the Horizon dashboard.

Allocate

The process of taking floating IP address from the address pool so it can be associated with a fixed IP on a Nova virtual machine instance.

Advanced Message Queuing Protocol (AMQP)

The open standard messaging protocol used by Nova for intra-service communications, provided by RabbitMQ (the default), Qpid or ZeroMQ.

Amazon Kernel Image (AKI)

Both a virtual machine container format and a virtual machine disk format, supported by Glance.

Amazon Machine Image (AMI)

Both a virtual machine container format and a virtual machine disk format, supported by Glance.

Amazon Ramdisk Image (ARI)

Both a virtual machine container format and a VM disk format, supported by Glance.

Anvil

A project to port the shell script based project named devstack to Python.

Apache

The most common web server software presently being used on the Internet.

Apache License 2.0

All OpenStack core projects are provided under the terms of the Apache License 2.0 license.

API Endpoint

The daemon, worker or service that a client communicates with in order to access an API. API endpoints can provide any number of services such as Keystone authentication, sales data, performance metrics, Nova virtual machine commands, census data, and so on.

API Extension

A feature of Nova and Quantum that allows custom modules to extend their core APIs.

API Extension Plug-in

Alternative term for a Quantum plug-in or Quantum API extension.

API Key

Alternative term for an API token.

API Server

Any node running a daemon or worker that provides an API endpoint.

API Token

A token that is sent along with API requests and is used by OpenStack to verify if the client is authorized to execute the requested operation.

API Version

In OpenStack a project's API version is part of the URL (eg: example.com/nova/v2/foobar vs example.com/nova/v1/foobar).

Application Programming Interface (API)

A collection of specifications used to access a service, application, or program. Includes service calls, required parameters for each call, and the expected return values.

Apache

The most common web server software presently being used on the Internet.

Applet

A Java program that can be embedded into a web page.

Application Server

A piece of software that makes available another piece of software over a network.

arptables

Used along with iptables, ebtables, and ip6tables in Nova to provide firewall services.

ASPs

An abbreviation for Application Service Providers. These are companies that rent specialized applications that help businesses and organizations provide additional services with less cost.

Associate

The process associating a Nova floating IP address to a fixed IP address.

Asynchronous !JavaScript and XML (AJAX)

Used extensively in Horizon.

ATA over Ethernet (AoE)

The ATA disk storage protocol tunneled within Ethernet, currently not supported in Nova.

Attach

The process of connecting a VIF or vNIC to a L2 network in Quantum. In the context of Nova this is the process of connecting a storage volume to an instance.

Attachment (network)

Association of an interface identifier to a logical port, which represent 'plugging' an interface into a port.

Auditing

Provided in Nova via the system usage data facility.

Auditor

A worker processes that verifies the integrity of Swift's objects, containers, and accounts. Auditors (plural) is the collective term for Swift's account auditor, container auditor, and object auditor.

Austin

Project name for the initial release of OpenStack.

Auth Node

Alternative term for a Swift authorization node.

Authentication

The process of confirming the user, process, or client is really who they say they are via private key, secret token, password, fingerprint, or similar method.

Authentication Token

A string of text provided to the client after they authenticate successfully, must be provided by the user or process in subsequent requests to the API endpoint.

AuthN

The component of Keystone that provides authentication services.

Authorization

The act of verifying that a user, process, or client can perform the reuqested action (delete a Swift object, list a Swift container, start a Nova virtual machine, reset a user's password, etc).

Authorization Node

A Swift node that provides authorization services.

AuthZ

The component of Keystone that provides high-level authorization services.

Auto ACK

Configuration setting within Nova's RabbitMQ that enables or disables message acknowledgement, enabled by default.

Auto Declare

A Nova RabbitMQ setting that determines if a message exchange is automatically created when the program starts.

Availability Zone

An Amazon EC2 concept of an isolated area that is used for fault tolerance, not to be confused with an OpenStack Nova zone or cell.

B

Backend

General term for interactions and processes that are obfuscated from the user such as Nova mounting a volume, a daemon sending data to an iSCSI target, or Swift checking the integrity of an object.

Backend Catalog

The storage method used by Keystone's catalog service to store and retrieve information about API endpoints that are available to the client. Examples include a SQL database, LDAP database, or KVS backend.

Backend Store

Describes the persistent data store used to save and retrieve a service's information such as a listing of Swift's objects, the current state of a Nova virtual machine, a list of user names and so on. Method that Glance uses to retrieve and store virtual machine images, options include Swift, local file system, S3, or HTTP.

Bandwidth

The amount of available data used by communication resources such as the Internet. It refers the amount of data that is used to download things or the amount of data available to download.

Bare

A Glance container format that indicates there is no container for the virtual machine image.

Bexar

A grouped release of projects related to OpenStack that came out in February of 2011. It included Compute (nova) and Object Storage (swift) only.

Binary

Information that consists solely of ones and zeroes, which is the language of computers.

Bit

A bit is a single digit number that is in base of 2 (either a zero or one). Bandwidth usage is measured in bits-per-second.

Bit Torrent

A peer-to-peer system that legally shares files such as legal software updates, movies and other resources.

Block Migration

A method of virtual machine live migration used by KVM to evacuate instance(s) from one host to another with very little downtime during a user-initiated switch-over, does not require shared storage, supported by Nova.

Bootable Disk Image

Type of virtual machine image that exists as a single, bootable file.

Bootstrap Protocol (BOOTP)

Provided in Nova via the dnsmasq daemon when using either the FlatDHCP manager or VLAN manager network manager.

BPS

Stands for bit-per-second, the most universal measurement of how quickly data is transferred from place to place.

Browser

Any client software that allows a computer or device to access the Internet (Microsoft Internet Explorer, Mozilla Firefox, Google Chrome, etc…).

Builder File

Contains a Swift ring's configuration information and is used to re-configure the ring or to re-create it from scratch after a serious failure.

Button Class

A group of related button types within Horizon. Buttons to start/stop/suspend virtual machines are in one class, buttons to associate and dissassociate floating IP addresses are in another, and so on.

Byte

Set of bits that make up a single character; there are usually 8 bits to a byte.

C

Cache Pruner

An executable program that is used to keep Glance's virtual machine image cache at or below its configured maximum size.

Cactus

A grouped release of projects related to OpenStack that came out in the spring of 2011. It included Compute (nova), Object Storage (swift), and the Image service (glance).

CALL

One of the RPC primitives used by OpenStack's message queue software, sends a message and waits for a response.

Capability

Defines a cell's resources (CPU, storage, networking), can apply to the cell as a whole or can only apply to specific services (CPU, storage, networking) within the cell.

Capacity Cache

A table within the Nova backend database that contains the current workload, amount of free RAM, number of virtual machines running on each host and is used when determining which virtual machine a host will start on.

Capacity Updater

A notification driver that monitors virtual machine instances and updates the capacity cache as needed.

CAST

One of the RPC primitives used by OpenStack's message queue software, sends a message and does not wait for a response.

Catalog

Contains a list of available API endpoints to a user after they authenticate to Keystone.

Catalog Service

A Keystone service that provides a list of available API endpoints to a user after they authenticate to Keystone.

Celiometer

An incubated project that aims to provide metering and billing facilities for OpenStack.

Cell

Provides logical partitioning of Nova resources in a child / parent relationship, requests are passed from parent cells to child cells if the parent cannot provide the requested resource.

Cell Forwarding

A Nova option that allows parent cells to pass resource requests to their child cells if the parent cannot provide the requested resource.

Cell Manager

The component of Nova that contains a list of each host's current capabilities within the cell and routes requests as appropriate.

CentOS

A Linux distribution that is compatible with OpenStack.

Ceph

Massively scalable distributed storage system that consists of an object store, block store and a POSIX-compatible distributed file system, compatible with OpenStack.

CephFS

The POSIX-compliant file system provided by Ceph.

Certificate Authority

Nova provides a simple certificate authority for cloudpipe VPNs and virtual machine image decryption.

Challenge-Handshake Authentication Protocol (CHAP)

An iSCSI authentication method supported by Nova.

Chance Scheduler

A scheduling method used by Nova that randomly chooses an available host from the pool.

Changes Since

A Nova API parameter that allows you to download changes to the requested item since you last request as opposed to downloading a new, fresh set of data and comparing it against the old data.

Chef

An operating system configuration management tool supported by OpenStack.

Child Cell

If a requested resource (CPU time, disk storage, memory) is not available in the parent cell, the request is forwarded to its associated child cell(s). If the child cell the fulfill the request it will, or it will attempt to pass the request to any of its children.

Cinder

A core project that maintains a Nova volume service for VMs as a separate project.

Cisco Quantum Plug-in

A Quantum plug-in for Cisco devices and technologies including UCS and Nexus.

Cloud Computing

Cloud computing is a model for enabling access to a shared pool of configurable computing resources (such as networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. The acronym OSSM stands for on-demand, self-service, scalable, and measurable

Cloud Controller

Collection of Nova components that represent the global state of the cloud, talks to services such as Keystone authentication, Swift object storage, and node/storage workers through a queue.

Cloud Controller Node

A node that runs network, volume, API, scheduler and image services. Each service may be broken out into separate nodes for scalability or availability.

Cloud Data Management Interface (CDMI)

SINA standard that defines a RESTful API for managing objects in the cloud, currently unsupported in OpenStack.

Cloud Infrastructure Management Interface (CIMI)

An in-progress specification for cloud management, currently unsupported in OpenStack.

cloud-init

A package commonly installed in virtual machine images that performs initialization of an instance after boot using information that it retrieves from the metadata service such as the SSH public key and user data.

cloudadmin

One of the default roles in Nova's RBAC system, allows for complete system access.

Cloudpipe

A service in Nova used to create VPNs on a per-project basis.

Cloudpipe Image

A pre-made virtual machine image that serves as a cloudpipe server, essentially OpenVPN running on Linux.

Cloudware

Refers to software that only exists on the Internet. There is no material product that resides on your local computer or disks.

Command Filter

Contains a list of allowed commands within Nova's rootwrap facility.

Community Project

A project that is not officially endorsed by the OpenStack Foundation. If the project is successful enough it may be elevated to an incubated project and then to a core project or may be simply merged with the main code trunk.

Compression

OpenStack supports compression at the Linux file system level but does not support compression for things such as Swift's objects or Glance's virtual machine images.

Compute API

The nova-api daemon that provides access to the Nova's services, can also communicate with some outside APIs such as Amazon's EC2 API.

Compute API Extension

Alternative term for a Nova API extension.

Compute Controller

The component of Nova that chooses suitable host(s) to start virtual machine instances on.

Compute Host

Physical host dedicated to running only compute nodes.

Compute Node

A node that runs Nova's nova-compute daemon, a virtual machine instance that provides a wide range of services such as a web server, performs analytics, provides a development environment or desktop, etc.

Compute Service

Alternative term for the component of Nova that manages virtual machines.

Compute Service API

Alternative term for Nova's Compute API.

Compute Worker

Nova component that runs on each compute node and manages the virtual machine instance lifecycle (run, reboot, terminate, attach/detach volumes, etc), provided by the nova-compute daemon.

Concatenated Object

A segmented large object within Swift that is put back together again and then sent to the client.

Consistency Window

The amount of time it takes for a new Swift object to become accessible to all clients.

Console Log

Contains the output from a Linux virtual machine's console in Nova.

Container

Used to organize and store objects within Swift, similar to the concept as a Linux directory but cannot be nested. Alternative term for a Glance container format.

Container Auditor

Checks for missing replicas or incorrect objects in the specified Swift containers via queries to the sqlite backend database.

Container Database

A sqlite database that contains Swift containers and related metadata and is accessed by the container server

Container Format

The "envelope" used by Glance to store a virtual machine image and it's associated metadata (machine state, OS disk size, etc).

Container Server

Component of Swift that manages containers.

Container Service

The component of Swift that provides container services (create, delete, list, etc).

Controller Node

Alternative term for a cloud controller node.

Cookie

Information that web pages save and send back as a way to recognize a user so that on succeeding visits, the users are easily recognized.

Core API

Depending on context this may mean OpenStack's core API (the OpenStack API) or the main API of a specific core project (Nova, Quantum, Glance, etc).

Core Project

An official OpenStack project. Currently consists of Compute (Nova), Object Storage (Swift), Image Service (Glance), Identity (Keystone), Dashboard (Horizon), Networking (Quantum), and Volume (Cinder).

Cost

Under Nova's distributed scheduler this is calculated by looking at the capabilities of each host relative to the flavor of the virtual machine instance being requested.

Credentials

Data that is only known to or accessible by a user that is used to verify the user is who they say they are and presented to the server during authentication. Examples include a password, secret key, digital certificate, fingerprint, and so on.

Crowbar

An open source community project by Dell that aims to provide all necessary services to quickly deploy clouds.

Current Workload

An element of the Nova capacity cache that is calculated based on the number of build, snapshot, migrate, and resize operations currently in progress on a given host.

Customer

Alternative term for a tenant.

Customization Module

A user-created Python module that is loaded by Horizon in order to change the look and feel of the dashboard.

D

Daemon

A process that runs in the background and waits for requests, may or may not listen on a TCP or UDP port, not to be confused with a worker.

Dashboard

The web-based management interface for OpenStack, an alternative name for Horizon.

Database ID

A unique identifier given to each replica of a Swift database.

Database Replicator

The component of Swift that copies changes in the account, container, and object databases to other nodes.

Data Encryption

Both Glance and Nova support encrypted virtual machine images (but not instances). In-transit data encryption is supported in OpenStack using technologies such as HTTPS, SSL, TLS, SSH. Swift does not support object encryption at the application level but may support storage that uses disk encryption.

Deallocate

The process of removing the association between a floating IP address and a fixed IP address thus returning the floating IP to the address pool.

Debian

A Linux distribution that is compatible with OpenStack.

Deduplication

The process of finding duplicate data at the disk block, file, and/or object level in order to minimize storage use, currently unsupported within OpenStack.

Default Panel

The default panel that is displayed when a user accesses the Horizon dashboard.

Default Tenant

New users are assigned to this Keystone tenant if no tenant is specified when a user is created.

Default Token

A Keystone token that is not associated with a specific tenant and is exchanged for a scoped token.

Delayed Delete

An option within Glance so that rather than immediately delete an image, it is deleted after a pre-defined number of seconds.

Delivery Mode

Setting for Nova's RabbitMQ message delivery mode, can be set to eitheer transient or persistent.

Deprecated Auth

An option within Nova that allows administrators to create and manage users via the nova-manage command as opposed to using Keystone.

developer

One of the default roles in Nova's RBAC system and is the default role assigned to a new user.

Device

In the context of Swift this refers to the underlying storage device.

Device ID

Maps Swift's partitions to physical storage devices.

Device Weight

Used to distribute the partitions among Swift's devices, usually proportional to the device's storage capacity.

DevStack

Community project that uses shell scripts to to quickly build complete OpenStack development environments.

DHTML

Stands for Dynamic HyperText Markup Language. Used to refer to pages that use HTML, JavaScript, and CCS to allow users to interact with a web page or show simple animation.

Diablo

A grouped release of projects related to OpenStack that came out in the fall of 2011, the fourth release of OpenStack. It included Compute (nova 2011.3), Object Storage (swift 1.4.3), and the Image service (glance).

Direct Consumer

An element of Nova's RabbitMQ that comes to life when a RPC call is executed. It connects to a direct exchange via a unqiue exclusive queue, sends the message, and terminates.

Direct Exchange

A routing table that is created within Nova's RabbitMQ during RPC calls, one is created for each RPC call that is invoked.

Direct Publisher

Element of RabbitMQ that provides a response to an incoming MQ message.

Disassociate

The process of removing the association between a floating IP address and fixed IP and thus returning the floating IP address to the address pool.

Disk Encryption

The ability to encrypt data at the file system, disk partition or whole disk level, supported within Nova virtual machines.

Disk Format

The underlying format that a virtual machine's disk image is stored as within Glance's backend store (AMI, ISO, QCOW2, VMDK, etc).

Dispersion

Swift provides tools to test and ensure dispersion of objects and containers in order to ensure fault tolerance.

Django

A web framework used extensively in Horizon.

dnsmasq

Daemon that provides DNS, DHCP, BOOTP, and TFTP services, used by Nova's VLAN manager and FlatDHCP manager.

Domain Name Service (DNS)

Nova supports associating DNS entries with floating IP addresses, nodes or cells so host names are consistent across reboots.

Download

The transfer of data – usually in the form of files – from one computer to another.

DNS

The Domain Name System (DNS) is a system by which Internet domain name-to-address and address-to-name resolutions are determined. All domains and their components, such as mail servers, utilize DNS to resolve to the appropriate locations. DNS servers are usually set up in a master-slave relationship such that failure of the master invokes the slave. DNS servers may also be clustered or replicated such that changes made to one DNS server are automatically propagated to other active servers.

A system by which Internet domain name-to-address and address-to-name resolutions are determined. Stands for Domain Name System. DNS helps navigate the Internet by translating the IP address into an address that is easier to remember (for example, translating 111.111.111.1 into www.yahoo.com).

DNS Record

A record that specifies information about a particular domain and belongs to the domain.

Domain

Is a name that identifies a web site and separates it from other sites. Often, the domain name will have 2 or more parts that are separated by dots (i.e. yahoo.com, usa.gov, Harvard.edu or mail.yahoo.com).

A domain is an entity/container of all DNS-related information containing one or more records.

Domain Name System

A system by which Internet domain name-to-address and address-to-name resolutions are determined. DNS is the acronym for Domain Name System.

Durable Exchange

Nova RabbitMQ message exchange that will remain active when the server restarts.

Durable Queue

A Nova RabbitMQ message queue that will remain active when the server restarts.

Dynamic Host Configuration Protocol (DHCP)

A method to automatically configure a host's networking configuration at boot time, provided by both Quantum and Nova.

E

EBS Boot Volume

An Amazon EBS storage volume that contains a bootable virtual machine image, currently unsupported in OpenStack.

ebtables

Used in Nova along with arptables, iptables, and ip6tables to create firewalls and to ensure isolation of network communications.

EC2

Amazon's commercial compute product, similar to Nova.

EC2 Access Key

Used along with an EC2 secret key to access Nova's EC2 API.

EC2 API

OpenStack supports accessing the Amazon EC2 API via Nova.

EC2 Compatibility API

Component of Nova that allows OpenStack to communicate with Amazon's EC2

EC2 Secret Key

Used along with an EC2 access key when communicating with Nova's EC2 API, is used to digitally sign each request.

Elastic Block Storage (EBS)

Amazon's commercial block storage product.

Empty Role

Keystone role with no capabilities, allows the administrator to later add capabilities to the role as necessary.

Encryption

OpenStack supports encryption technologies such as HTTPS, SSH, SSL, TLS, digital certificates, and data encryption.

Endpoint

Alternative term for an API endpoint.

Endpoint Registry

Alternative term for a Keystone catalog.

Endpoint Template

A list of URL and port number endpoints that indicate where a service (object storage, compute, identity, etc) can be accessed.

Entity

A generic term for any piece of hardware or software desiring to connect to the network services provided by Quantum, the Network Connectivity service. An entity may make use of Quantum by implementing a VIF.

Ephemeral Image

A virtual machine image that does not save changes made to it's volumes and reverts them to their original state after the instance is terminated.

Ephemeral Volume

Volume that does not save the changes made to it and reverts to its original state when the current user relinquishes control.

Essex

A grouped release of projects related to OpenStack that came out in April 2012, the fifth release of OpenStack. It included Compute (nova 2012.1), Object Storage (swift 1.4.8), Image (glance), Identity (keystone), and Dashboard (horizon).

ESX

One of the hypervisors supported by OpenStack.

ESXi

One of the hypervisors supported by OpenStack.

ETag

MD5 hash of an object within Swift, used to ensure data integrity.

euca2ools

A collection of command line tools for administering virtual machines, most are compatible with OpenStack.

Eucalyptus Kernel Image (EKI)

Used along with an ERI to create an EMI.

Eucalyptus Machine Image (EMI)

Virtual machine image container format supported by Glance.

Eucalyptus Ramdisk Image (ERI)

Used along with an EKI to create an EMI.

Evacuate

The process of migrating one or all virtual machine instances from one host to another, compatible with both shared storage live migration and block migration.

Exchange

Alternative term for a RabbitMQ message exchange.

Exchange Type

A routing algorithm in Nova's RabbitMQ.

Exclusive Queue

Connected to by a direct consumer in RabbitMQ / Nova, the message can only be consumed by the current connection.

Extended Attributes (xattrs)

File system option that allows for storage of additional information beyond owner, group, permissions, modification time and so on. Swift's underlying file system must support extended attributes.

Extension

Alternative term for a Nova API extension or plug-in. In the context of Keystone this is a call that is specific to the implementation (eg: adding support for OpenID).

Extra Specs

Allows additional requirements to be specified when Nova determines where to start a new instance, examples include a minimum amount of network bandwidth or a GPU.

F

FakeLDAP

An easy method to create a local LDAP directory for testing Keystone and Nova, requires Redis.

Fan-out Exchange

Within RabbitMQ and Nova it is the messaging interface that is used by the scheduler service to receive capability messages from the compute, volume, and network nodes.

Fedora

A Linux distribution compatible with OpenStack.

Fibre Channel

Storage protocol similar in concept to TCP/IP, encapsulates SCSI commands and data.

Fibre Channel over Ethernet (FCoE)

The fibre channel protocol tunneled within ethernet.

Fill-first Scheduler

Nova scheduling method that attempts to fill a host with virtual machines rather than starting new virtual machines on a variety of hosts.

Filter

The step of the Nova scheduling process where hosts that cannot run the virtual machine(s) are eliminated and will not be chosen.

Firewall

Used to restrict communications between hosts and/or nodes, implemented in Nova using iptables, arptables, ip6tables and etables.

Fixed IP Address

An IP address that is associated with the same instance each time that instance boots, generally not accessible to end users or the public internet, used for management of the instance.

FlatDHCP Manager

Component of Nova that provides dnsmasq (DHCP, DNS, BOOTP, TFTP) and radvd (routing) services.

Flat Manager

Component of Nova that gives IP addresses to authorized nodes and assumes DHCP, DNS, and routing configuration and services are provided by something else.

Flat Mode Injection

A Nova networking method where the OS network configuration information is injected into the virtual machine image before the instance starts.

Flavor

Alternative term for a virtual machine instance type.

Flavor ID

UUID for each Nova / Glance virtual machine flavor or instance type.

Floating IP Address

An IP address that a Nova project can associate with one of their virtual machines so the instance has the same public IP address each time it boots. You create a pool of floating IP addresses and assign them to instances as they are launched to maintain a consistent IP address for maintaining DNS assignment.

FormPost

Swift middleware that allows users to upload (post) an image via a form on a web page.

Folsom

A grouped release of projects related to OpenStack that came out in the fall of 2012, the sixth release of OpenStack. It includes Compute (nova), Object Storage (swift), Identity (keystone), Networking (quantum), Image service (glance) and Volumes or Block Storage (cinder).

Frontend

The point where a user interacts with a service, can be an API endpoint, the Horizon dashboard, or a command line tool.

G

Gateway

Hardware or software that translates between two different protocols.

GIF

Stands for Graphic Interchange Format, a type of image file that is commonly used for animated images on web pages.

Glance

The name of the project that provides the OpenStack Image Service.

Glance API Server

Processes client requests for VMs, updates Glance metadata on the registry server, and communicates with the store adapter to upload VM images from the backend store.

Glance Registry

Alternative term for Glance's image registry.

Global Endpoint Template

Keystone endpoint template that contains services available to all tenants.

GlusterFS

A file system designed to aggregate NAS hosts, compatible with OpenStack.

Golden Image

A method of operating system installation where a finalized disk image is created and then used by all nodes without modification.

Graphics Processing Unit (GPU)

Choosing a host based on the existence of a GPU is currently unsupported in OpenStack.

Green Threads

The cooperative threading model used by Python, reduces race conditions, and only context switches when specific library calls are made. Each OpenStack service is it's own thread.

Grizzly

Project name for the seventh release of OpenStack.

Guest OS

An operating system instance running under the control of a hypervisor.

H

Handover

An object state in Swift where a new replica of the object is automatically created due to a drive failure.

Hard Reboot

A type of reboot where a physical or virtual power button is pressed as opposed to a graceful, proper shutdown of the operating system.

Heat

An incubated project that aims to orchestrate multiple cloud applications for OpenStack.

Horizon

The project that provides the OpenStack Dashboard.

Horizon Plugin

A plugin for the OpenStack dashboard (Horizon).

Host

A physical computer, not a virtual machine instance (node).

Host Aggregate

A method to further subdivide availability zones into hypervisor pools, a collection of common hosts.

Host Bus Adapter (HBA)

Device plugged into a PCI slot such as a fibre channel or network card.

Hypertext Transfer Protocol Secure (HTTPS)

Encrypted HTTP communications using SSL or TLS, most OpenStack API endpoints and many inter-component communications support HTTPS communication.

Hyper-V

One of the hypervisors supported by OpenStack, actions are underway to add full support.

Hypervisor

Software that arbitrates and controls virtual machine access to the actual underlying hardware.

Hypervisor Pool

A collection of hypervisors grouped together via host aggregates.

HTTP

Stands for HyperText Transfer Protocol, the protocol that tells browsers where to go to find information.

Hypertext

Any kind of text that contains a link to some other site, commonly found in documents where clicking on a word or words opens up a different web site.

I

ID Number

Unique numeric identifier associated with each user in Keystone, conceptually similar to a Linux or LDAP UID.

Identity API

Alternative term for the Identity Service API.

Identity Backend

The source used by Keystone to retrieve user information an OpenLDAP server for example.

Identity Service

OpenStack's identity service is provided by the Keystone project.

Identity Service API

The API used to access Keystone's identity service.

Image

A file that contains a complete Linux virtual machine, used to create or rebuild a server. Cloud providers can provide a number of pre-built OS images by default. You may also create custom images from cloud servers you have launched. These custom images are useful for backup purposes or for producing “gold” server images if you plan to deploy a particular server configuration frequently.

Image API

Glance's API endpoint for management of virtual machine images.

Image Cache

Used by Glance to allow images on the local host to be used rather than re-downloading them from the image server each time one is requested.

Image Identifier

Combination of URI and UUID used to access Glance virtual machine images via the image API.

Image Membership

A list of tenants that can access a given virtual machine image within Glance.

Image Owner

The Keystone tenant who owns a Glance virtual machine image.

Image Registry

A list of virtual machine images that are available via Glance.

Image Service API

Alternative name for Glance's image API.

Image Status

The current status of a virtual machine image in Glance, not to be confused with the status of a running instance.

Image Store

The backend store used by Glance to store virtual machine images, options include Swift, local file system, S3, or HTTP.

Image UUID

UUID used by Glance to uniquely identify each virtual machine image.

Incubated Project

A community project may be elevated to this status and is then promoted to a core project.

Ingress Filtering

The process of filtering incoming network traffic, supported by Nova.

Injection

The process of putting a file into a virtual machine image before the instance is started.

Instance

An instance is a virtual machine running or in a known state such as "suspended" that can be used like a hardware server.

Instance ID

Unique identifier that is specific to each running Nova virtual machine instance.

Instance State

The current state of a Nova virtual machine image.

Instance Type

Describes the parameters of the various virtual machine images that are available to users, includes parameters such as CPU, storage, and memory. Alternative term for flavor.

Instance Type ID

Alternative term for a flavor ID.

Instance UUID

Unique identifier assigned to each Nova virtual machine instance.

Interface ID

Unique identifier for a Quantum VIF or vNIC in the form of a UUID.

ISO9960

One of the virtual machine image disk formats supported by Glance.

IP Address

Number that is unique to every computer system on the Internet. Two versions of the Internet Protocol (IP) are in use for addresses: IPv4 and IPv6.

IP Address Management (IPAM)

The process of automating IP address allocation, deallocation, and management. Currently provided by Nova, Melange, and Quantum but will eventually be folded into Quantum.

ip6tables

Used along with arptables, ebtables, and iptables to create firewalls in Nova.

iptables

Used along with arptables, ebtables, and ip6tables to create firewalls in Nova.

IPv6

Supported by Nova, Quantum, and other components of OpenStack.

iSCSI

The SCSI disk protocol tunneled within ethernet, supported by Nova, Swift, and Glance.

ISP

Refers to Internet Service Provider, which is any business that provides Internet access to individuals or businesses.

itsec

One of the default roles in Nova's RBAC system, allows the user to quarantine any project's instance.

J

Java

A programming language that is used to create systems that involve more than one computer by way of a network.

JavaScript

A scripting language used in web pages.

JavaScript Object Notation (JSON)

One of the supported response formats in OpenStack.

Jenkins

Tool used for OpenStack development.

K

Kernel-based Virtual Machine (KVM)

One of the hypervisors supported by OpenStack.

Keystone

The name of the project that provides OpenStack Identity services.

Kickstart

A tool to automate system configuration and installation on Red Hat, Fedora, and CentOS based Linux distributions.

L

Large Object

An object within Swift that is larger than 5 gigabytes.

Launchpad

OpenStack's collaboration site.

Layer-2 network

A virtual Ethernet network managed by the Quantum service. For the time being, Quantum will manage only Ethernet networks.

libvirt

Virtualization API library used by OpenStack to interact with many of it's supported hypervisors.

Linux Bridge

Software used to allow multiple virtual machines to share a single physical NIC within Nova.

Linux Bridge Quantum Plug-in

Plugin that allows a Linux Bridge to understand Quantum's port, interface attachment, and other abstractions.

Linux Containers (LXC)

One of the hypervisors supported by OpenStack.

Live Migration

The ability within Nova to move running virtual machine instances from one host to another with only a small service interruption during switch-over.

Load Balancer

A load balancer is a logical device which belongs to a cloud account. It is used to distribute workloads between multiple back-end systems or services, based on the criteria defined as part of its configuration.

Load Balancing

The process of spreading client requests between two or more nodes in order to improve performance and availability.

M

Management API

Alternative term for an admin API.

Management Network

A network segment used for administration, not accessible to the public internet.

Manager

Logical groupings of related code such as Nova's volume manager or network manager.

Manifest

Used to track segments of a large object within Swift.

Manifest Object

A special Swift object that contains a large object's manifest.

Meta-Data Server (MDS)

Stores CephFS metadata.

Melange

Project name for OpenStack Network Information Service, will be merged with Quantum.

Membership

The association between a Glance virtual machine image and a tenant, allows images to be shared with specified tenant(s).

Membership List

Contains a list of tenants that can access a given virtual machine image within Glance.

memcached

A distributed memory object caching system, used by Swift for caching.

Memory Overcommit

Alternative term for RAM overcommit.

Message Broker

The software package used to provide AMQP messaging capabilities within Nova, default is RabbitMQ.

Message Bus

The main virtual communication line used by all AMQP messages for inter-cloud communications within Nova.

Message Queue

Passes requests from clients to the appropriate workers and returns the output to the client once the job is complete.

Migration

The process of moving a virtual machine instance from one host to another.

Monitor (Mon)

Component of Ceph that communicates with external clients, checks data state and consistency, and performs quorum functions.

Multi-factor Authentication

Authentication using two or more sources such as a password and a private key, currently unsupported in Keystone.

MultiNic

Facility in Nova that allows each virtual machine instance to have more than one VIF connected to it.

N

Nebula

Released as open source by NASA in 2010 and is the basis for Nova.

netadmin

One of the default roles in Nova's RBAC system, allows the user to allocate publicly accessible IP addresses to instances and change firewall rules.

NetApp Volume Driver

Allows Nova to communicate with NetApp storage devices via NetApp's OnCommand Provisioning Manager.

network

A virtual network providing connectivity between entities, i.e.: collection of virtual ports sharing network connectivity. In the Network Connectivity (Quantum) terminology, a network is always a Layer-2 network.

Network Address Translation (NAT)

The process of modifying IP address information while in-transit, supported by Nova and Quantum.

Network Controller

Nova daemon that orchestrates the network configuration of nodes including includes IP addresses, VLANs, bridging, and manages routing for both public interfaces and private interfaces.

Network File System (NFS)

A method for making file systems available over the network, supported by OpenStack.

Network ID

Unique identifier assigned to each network segment within Quantum.

Network Manager

Component of Nova that manages various network components (firewall rules, IP address allocation, etc).

Network Node

Any Nova node that runs the network worker daemon.

Network Segment

Represents a virtual, isolated OSI layer 2 subnet in Quantum.

Network Time Protocol (NTP)

A method of keeping a host's or node's clock correct via communications with a trusted, accurate time source.

Network UUID

Unique identifier for a Quantum network segment.

Network Worker

The nova-network worker daemon, provides services such as giving an IP address to a booting Nova instance.

Nexenta Volume Driver

Provides support for NexentaStor devices in Nova.

Nicira NVP Quantum Plugin

Provides support for Nicira's Network Virtualization Platform (NVP) in Quantum.

No ACK

Disables server-side message acknowledgement in Nova's RabbitMQ, increases performance but decreases reliability.

Node

A virtual machine instance running on a host.

non-Durable Exchange

Message exchange that is cleared when the service restarts, it's data is not written to persistent storage.

non-Durable Queue

Message queue that is cleared when the service restarts, it's data is not written to persistent storage.

non-Persistent Volume

Alternative term for an ephemeral volume.

Nova

The name of the project that provides OpenStack Compute.

Nova API

Alternative term for Nova's compute API.

Nova Network

Component of Nova that manages IP address allocation, firewalling, and other network related tasks.

Nova Volume

The component of Nova that manages storage volumes, currently being split off into a separate project named Cinder.

O

Object

A BLOB of data held by Swift, can be in any format.

Object API

Alternative term for the Swift object API.

Object Auditor

Opens all of an object server's objects and verifies the MD5 hash, size, and metadata of each.

Object Expiration

A configurable option within Swift to automatically delete objects after a specified amount of time has passed or a certain date is reached.

Object Hash

Uniquely identifier for a Swift object.

Object Path Hash

Used by Swift to determine object's location within the ring, maps objects to partitions.

Object Replicator

Component of Swift that copies and object to remote partitions for fault tolerance.

Object Service API

Alternative term for Swift's object API.

Object Server

Component of Swift that is responsible for managing objects.

Object Storage

Provides eventually consistent and redundant storage and retrieval of fixed digital content.

Object Versioning

Allows a user to set a flag on a Swift container so all objects within the container are versioned.

Oldie

Term for a Swift process that has been running for a long time, may be an indication of a hung process.

OpenID

Currently unsupported in OpenStack.

OpenLDAP

An open source LDAP server, supported by both Nova and Keystone.

OpenStack API (OSAPI)

The core OpenStack API.

OpenSUSE

A Linux distribution that is compatible with OpenStack.

Open Cloud Computing Interface (OCCI)

A standardized interface for managing compute, data, and network resources, currently unsupported in OpenStack.

Open Virtualization Format (OVF)

Standard for packaging virtual machine images, supported in OpenStack.

Open vSwitch Quantum Plug-in

A plugin for Quantum used to provide support for Open vSwitch.

Orphan

In the context of Swift this is a process that is not terminated after an upgrade, restart, or reload of the service.

Object Storage Device OSD

The Ceph storage daemon.

P

Parent Cell

If a requested resource (CPU time, disk storage, memory) is not available in the parent cell, the request is forwarded to it's associated child cell(s).

Partition

A unit of storage within Swift used to store objects, exists on top of devices, replicated for fault tolerance.

Partition Index

Contains the locations of all Swift partitions within the ring.

Partition Shift Value

Used by Swift to determine which partition data should reside on.

Pause

A virtual machine state where no changes occur (no changes in memory, network communications stop, etc), the virtual machine is frozen but not shut down.

PCI Passthrough

Allows guest virtual machines to have exclusive access to a PCI device, currently unsupported in OpenStack.

Persistent Message

A message that is stored both in memory and on disk, the message is not lost after a failure or restart.

Persistent Volume

Changes to these types of disk volumes are saved.

Personality File

A file used to customize a Nova instance, can be used to inject SSH keys or a specific network configuration.

Plugin

Software component providing the actual implementation for Quantum APIs, or for Compute APIs, depending on the context.

Policy Service

Component of Keystone that provides a rule management interface and a rule based authorization engine.

Port

A virtual network port within Quantum, VIFs / vNICs are connected to a port.

Port UUID

Unique identifier for a Quantum port.

preseed

A tool to automate system configuration and installation on Debian based Linux distributions.

Private Image

Glance virtual machine images that are only available to specified tenants.

Private IP Address

An IP address used for management and administration, not available to the public internet.

Project

A logical grouping of users within Nova, used to define quotas and access to virtual machine images.

Project ID

User defined alpha-numeric string in Nova, the name of a project.

Project VPN

Alternative term for a cloudpipe.

Provider

Nova term that describes an administrator who has access to all hosts and instances.

Proxy Node

A node that provides the Swift proxy service.

Proxy Server

Users of Swift interact with the service via the proxy server which in-turn looks up the location of the requested data within the ring and returns the results to the user.

Public API

An API endpoint used for both service to service communication and end user interactions.

Public Image

A Glance virtual machine image that is available to all tenants.

Public IP Address

An IP address that is accessible to end-users.

Puppet

An operating system configuration management tool supported by OpenStack.

Python

Programming language used extensively in OpenStack.

Q

QEMU Copy On Write 2 (QCOW2)

One of the virtual machine image disk formats supported by Glance.

Qpid

Message queue software supported by OpenStack, an alternative to RabbitMQ.

Quantum

The project that provides a network connectivity abstraction layer to OpenStack Compute.

Quantum API

API used to access Quantum, provides and extensible architecture to allow custom plugin creation.

Quantum Manager

Allows Nova and Quantum integration thus allowing Quantum to perform network management for Nova virtual machines.

Quantum Plugin

Interface within Quantum that allows organizations to create custom plugins for advanced features such as QoS, ACLs, or IDS.

Quarantine

If Swift finds objects, containers, or accounts that are corrupt they are placed in this state, are not replicated, cannot be read by clients, and a correct copy is re-replicated.

Quick EMUlator (QEMU)

One of the hypervisors supported by OpenStack, generally used for development purposes.

Quota

Nova provides the ability to set resource limits on a per-project basis.

R

RabbitMQ

The default message queue software used by OpenStack.

Rackspace Cloud Files

Released as open source by Rackspace in 2010, the basis for Swift.

radvd

The router advertisement daemon, used by Nova's VLAN manager and FlatDHCP manager to provide routing services for virtual machine instances.

RAM Filter

Nova setting that allows or disallows RAM overcommitment.

RAM Overcommit

The ability to start new virtual machine instances based on a host's actual memory usage as opposed to basing the decision on the amount of RAM each running instance thinks it has available.

Rate Limit

Configurable option within Swift to limit database writes on a per-account and/or per-container basis.

raw

One of the virtual machine image disk formats supported by Glance, an unstructured disk image.

RADOS Block Device (RBD)

Component of Ceph that allows a Linux block device to be striped over multiple distributed data stores.

Rebalance

The process of distributing Swift partitions across all drives in the ring, used during initial ring creation and after ring reconfiguration.

Reboot

The reboot function allows for either a soft or hard reboot of a server. With a soft reboot, the operating system is signaled to restart, which allows for a graceful shutdown of all processes. A hard reboot is the equivalent of power cycling the server. The virtualization platform should ensure that the reboot action has completed successfully even in cases in which the underlying domain/vm is paused or halted/stopped.

Rebuild

The rebuild function removes all data on the server and replaces it with the specified image. Server ID and IP addresses remain the same.

Recon

A component of Swift used to collect metrics.

Record

A DNS record belongs to a particular domain and is used to specify information about the domain. There are several types of DNS records. Each record type contains particular information used to describe that record's purpose. Examples include mail exchange (MX) records, which specify the mail server for a particular domain, and name server (NS) records, which specify the authoritative name servers for a domain.

Record ID

A number within a database that is incremented each time a change is made, used by Swift when replicating.

Red Hat Enterprise Linux (RHEL)

A Linux distribution that is compatible with OpenStack.

Red Dwarf Lite

Community project that aims to provide database as a service.

Registry

Alternative term for the Glance image registry.

Registry Server

Glance service that provides virtual machine image metadata information to clients.

Reliable, Autonomic Distributed Object Store (RADOS)

A collection of components that provides object storage within Ceph, similar to Swift.

Remote Procedure Call (RPC)

The method used by Nova's RabbitMQ for intra-service communications.

Replication

The process of copying data to a separate physical device for fault tolerance and performance.

Replicator

Swift's backend process that creates and manages object replicas.

Replica

Provides data redundancy and fault tolerance by creating copies of Swift objects, accounts, and containers so they are not lost when the underlying storage fails.

Replica Count

The number of replicas of the data within a Swift ring.

Request ID

Unique identifier assigned to each request sent to Nova.

Rescue Image

A special type of virtual machine image that is booted when an instance is placed into rescue mode, allows an administrator to mount the problematic instance's file systems to correct the problem.

Resize

The resize function converts an existing server to a different flavor, in essence, scaling the server up or down. The original server is saved for a period of time to allow rollback if there is a problem. All resizes should be tested and explicitly confirmed, at which time the original server is removed. All resizes are automatically confirmed after 24 hours if they are not confirmed or reverted.

RESTful

A kind of web service API that uses REST, or Representational State Transfer. REST is the style of architecture for hypermedia systems that is used for the World Wide Web.

Ring

An entity that maps Swift data to partitions, there is a separate ring for each service (account, object, and container).

Ring Builder

Builds and manages rings within Swift, assigns partitions to devices, and pushes the configuration to other storage nodes.

Role Based Access Control (RBAC)

Provides a pre-defined list of actions the user can take (start or stop virtual machines, reset passwords, etc), supported in both Keystone and Nova and can be configured using the Horizon dashboard.

Role ID

Alpha-numeric identifier assigned to each Keystone role.

rootwrap

A feature of Nova that allows the unprivileged "nova" user to run a specified list of commands as the Linux root user.

RPC Driver

Modular system that allows Nova's underlying message queue software to be changed (eg: from RabbitMQ to ZeroMQ or Qpid).

Round-robin Scheduler

Type of Nova scheduler that evenly distributes instances among available hosts.

Routing Key

Nova's direct exchanges, fanout exchanges, and topic exchanges use this to determine how to process a message, processing varies depending on exchange type.

rsync

Used by Swift to push object replicas.

RXTX Cap

Absolute limit on the amount of network traffic a Nova virtual machine instance can send and receive.

RXTX Quota

Soft limit on the amount of network traffic a Nova virtual machine instance can send and receive.

Ryu Quantum Plugin

Allows the Ryu Network Operating System to function as a Quantum OpenFlow controller.

S3

Object storage service by Amazon, similar in function to Swift, can act as a backend store for Glance virtual machine images.

S

Scheduler Manager

Component of Nova's that determines where virtual machine instances should start, uses modular design to support a variety of scheduler types.

Scoped Token

A Keystone API access token that is associated with a specific tenant.

Scrubber

Checks for and deletes unused virtual machine, the component of Glance that implements delayed delete.

Secret Key

String of text only known by the user, used along with an access key to make requests to Nova's API.

Secure Shell (SSH)

Open source tool used to access remote hosts via an encrypted communications channel, SSH key injection is supported by Nova.

Security Group

A set of network traffic filtering rules that are applied to a Nova instance.

Segmented Object

A Swift large object that has been broken up into pieces, the re-assembled object is called a concatenated object.

Server

Computer that provides explicit services to the client software running on that system, often managing a variety of computer operations.

A server is a virtual machine instance in the Cloud Servers system. Flavor and image are requisite elements when creating a server.

Server Image

Alternative term for a virtual machine image.

Server UUID

Unique identifier assigned to each Nova virtual machine instance.

Service Catalog

Alternative term for Keystone's catalog.

Service ID

Unique identifier assigned to each service that is available in Keystone's catalog.

Service Registration

Feature of Keystone that allows services such as Nova to automatically register with the catalog.

Service Tenant

Special Keystone tenant that contains all services listed in the catalog.

Service Token

An administrator defined token used by Nova to communicate securely with Keystone.

Session Backend

The method of storage used by Horizon to track client sessions such as local memory, cookies, a database, or memcached.

Session Persistence

Session persistence is a feature of the load balancing service. It attempts to force subsequent connections to a service to be redirected to the same node as long as it is online.

Session Storage

Component of Horizon that stores and tracks client session information, implemented via Django's sessions framework.

Shared IP Address

An IP address that can be assigned to a virtual machine instance within the shared IP group. Public IP addresses can be shared across multiple servers for use in various high availability scenarios. When an IP address is shared to another server, the cloud network restrictions are modified to allow each server to listen to and respond on that IP address (you may optionally specify that the target server network configuration be modified). Shared IP addresses can be used with many standard heartbeat facilities (e.g. keepalive) that monitor for failure and manage IP failover.

Shared IP Group

A shared IP group is a collection of servers that can share IPs with other members of the group. Any server in a group can share one or more public IPs with any other server in the group. With the exception of the first server in a shared IP group, servers must be launched into shared IP groups. A server may only be a member of one shared IP group.

Shared Storage

Block storage that is simultaneously accessible by multiple clients, an example is NFS.

Sheepdog

Distributed block storage system for QEMU, supported by OpenStack.

Simple Cloud Identity Management (SCIM)

Specification for managing identity in the cloud, currently unsupported by OpenStack.

Simple Scheduler

Volume scheduler type within Nova, deprecated in Folsom release.

Single-root I/O Virtualization (SR-IOV)

Alternative term for PCI pass-through, currently unsupported in OpenStack.

SmokeStack

Runs automated tests against the core OpenStack API, written in Rails.

Snapshot

A point-in-time copy of a storage volume, supported by OpenStack.

Soft Reboot

A controlled reboot where a virtual machine instance is properly restarted via operating system commands.

SolidFire Volume Driver

Nova volume driver for the SolidFire iSCSI storage appliance.

Spread-first Scheduler

Nova virtual machine scheduling algorithm that attempts to start new virtual machines on the host with the least amount of load.

SQL-Alchemy

An open source SQL toolkit for Python, used in OpenStack.

SQLite

A lightweight SQL database, used as the default persistent storage method in many OpenStack services.

StackTach

Community project that captures Nova AMQP communications, useful for debugging.

StaticWeb

WSGI middleware component of Swift that serves container data as a static web page.

Static IP Address

Alternative term for a fixed IP address.

Storage Backend

The method that a service uses for persistent storage such as iSCSI, NFS, or local disk.

Storage Manager

Component of XenAPI that provides a pluggable interface in order to support a wide variety of persistent storage backends.

Storage Manager Backend

A persistent storage method supported by XenAPI such as iSCSI or NFS.

Storage Node

A Swift node that provides container services, account services, and object services, controls the account databases, container databases, and object storage.

Storage Services

Collective name for Swift's object services, container services, and account services.

Strategy

Specifies the authentication source used by Glance or Keystone.

Suspend

Alternative term for a paused virtual machine instance.

Swap

Disk based virtual memory, used by operating systems to provide more memory than is actually available on the system.

swawth

An authentication and authorization service for Swift, implemented via WSGI middleware, uses Swift itself as the persistent backing store.

Swift

The project that provides OpenStack Object Storage services.

Swift All in One (SAIO)

Creates a full Swift development environment within a single virtual machine.

Swift Middleware

Collective term for components within Swift that allows for additional functionality.

Sync Point

Point in time since the last container and accounts database sync among nodes within Swift.

sysadmin

One of the default roles in Nova's RBAC system, allows the user add other users to his or her project, interact with virtual machine images that are associated with the project, and start and stop virtual machine instances.

System Usage

A component of Nova that along with the notification system collects metrics and usage information, can be used for billing.

Subdomain

A domain within a parent domain. Subdomains cannot be registered. Subdomains allow you to delegate domains. Subdomains can themselves have subdomains, so third-level, fourth-level, fifth-level, and deeper levels of nesting are possible.

SUSE Linux Enterprise Server (SLES)

A Linux distribution that is compatible with OpenStack.

T

TempAuth

An authentication facility within Swift that allows Swift itself to perform authentication and authorization, frequently used in testing and development.

Tempest

Automated software test suite designed to run against the OpenStack core project's trunk.

TempURL

A component of Swift's middleware that allows a user to create URLs for temporary object access.

Tenant

A group of users, used to isolate access to Nova resources, an alternative term for a Nova project.

Tenant API

An API that is accessible to tenants.

Tenant Endpoint

A Keystone API endpoint that is associated with one or more tenants.

Tenant ID

Unique identifier assigned to each tenant within Keystone, Nova's project IDs map to Keystone's tenant IDs.

Token

An alpha-numeric string of text used to access OpenStack APIs and resources.

Token Services

Component of Keystone that both manages and validates tokens after a user or tenant has been authenticated.

Tombstone

Used to mark Swift objects that have been deleted, ensures the object is not updated on another node after it has been deleted.

Topic Publisher

A process that is created when a RPC call is executed, used to push the message to the topic exchange.

Torpedo

Community project used to run automated tests against the OpenStack API.

Transaction ID

Unique identifier assigned to each Swift request, used for debugging and tracing.

Transient

Alternative term for non-durable.

Transient Message

A message that is stored in memory and is lost after the server is restarted.

Transient Exchange

Alternative term for a non-durable exchange.

Transient Queue

Alternative term for a non-durable queue.

U

Ubuntu

A Linux distribution that is compatible with OpenStack.

Unscoped Token

Alternative term for a Keystone default token.

Updater

Collective term for a group of Swift components that process queued and failed updates for containers and objects.

User

In Keystone each user is associated with one or more tenants, and in Nova they can be associated with roles, projects, or both.

User data

A blob of data that can be specified by the user when launching an instance. This data can be accessed by the instance via the metadata service or config drive. Commonly used for passing a shell script that is executed by the instance on boot.

User Mode Linux (UML)

One of the hypervisors supported by OpenStack.

V

VIF

A Virtual network InterFace plugged into a port of a Quantum network; typically a virtual network interface belonging to a VM

VIF UUID

Unique identifier assigned to each Quantum VIF.

VirtualBox

One of the hypervisors supported by OpenStack.

Virtual Central Processing Unit (vCPU)

Allows physical CPUs to be sub-divided and those divisions are then used by instances.

Virtual Disk Image (VDI)

One of the virtual machine image disk formats supported by Glance.

Virtual Hard Disk (VHD)

One of the virtual machine image disk formats supported by Glance.

Virtual IP

A virtual IP is an Internet Protocol (IP) address configured on the load balancer for use by clients connecting to a service that is load balanced. Incoming connections are distributed to back-end nodes based on the configuration of the load balancer.

Virtual Machine

An operating system instance running on top of a hypervisor, multiple VMs can run at the same time on the same physical host.

Virtual Machine Disk (VMDK)

One of the virtual machine image disk formats supported by Glance.

Virtual Machine Image

Alternative term for an image.

Virtual Network

A L2 network segment within Quantum.

Virtual Port

Attachment point where a virtual interface connects to a virtual network.

Virtual Private Network (VPN)

Provided by Nova in the form of cloudpipes, specialized instances that are used to create VPNs on a per-project basis.

Virtual Server

Alternative term for a virtual machine or guest.

VLAN Manager

Component of Nova that provides dnsmasq, radvd, and sets up forwarding to and from cloudpipe instances.

Virtual Machine Remote Control (VMRC)

Method to access virtual machine instance consoles using a web browser, supported by Nova.

Virtual Network Computing (VNC)

Open source GUI and CLI tools used for remote console access to virtual machines, supported by Nova.

Virtual Switch (vSwitch)

Software that runs on a host or node and provides the features and functions of a hardware based network switch.

Virtual VLAN

Alternative term for a virtual network.

VMware API

Nova supports interaction with VMware products via this API.

VNC Proxy

Nova component that provides users access to the consoles of their virtual machine instances via VNC or VMRC.

Volume

Disk-based data storage generally represented as an iSCSI target with a file system that supports extended attributes, can be persistent or ephemeral.

Volume API

Application Programming Interface on a separate endpoint for attaching, detaching, and creating block storage for Compute VMs.

Volume Controller

Component of Nova that oversees and coordinates storage volume actions.

Volume Driver

Alternative term for a volume plugin.

Volume ID

Unique identifier applied to each storage volume under Nova's control.

Volume Manager

Component of Nova that creates, attaches, and detaches persistent storage volumes.

Volume Node

A Nova node that runs the nova-volume daemon.

Volume Plugin

A plugin for Nova's volume manager, provides support for a new and specialized types of backend storage.

Volume Service API

Alternative term for the Nova volume API.

Volume Worker

The component of Nova that interacts with backend storage to manage the creation and deletion of volumes and the creation of compute volumes, provided by the nova-volume daemon.

vSphere

One of the hypervisors supported by OpenStack.

W

Weighted Cost

The sum of each cost used when deciding where to start a new virtual machine instance in Nova.

Weighing

Nova uses this process to determine how suited a job's VM instance(s) are to a particular host (not enough RAM on the host, too many CPUs on the host, etc).

Weight

Used by Swift storage devices to determine which storage device(s) are suitable for the job, devices are weighted by size.

Worker

A daemon that carries out tasks, for example the nova-volume worker attaching storage to an virtual machine instance. Workers listen to a queue and take action when new messages arrive.

X

XenServer

One of the hypervisors supported by OpenStack.

Xen API

Xen's administrative API, supported by Nova.

Xen Cloud Platform (XCP)

One of the hypervisors supported by OpenStack.

Xen Storage Manager Volume Driver

A Nova volume plugin that allows for communication with Xen's Storage Manager API.

Z

Zero MQ

Message queue software supported by OpenStack, an alternative to RabbitMQ.

Zuul

Tool used in OpenStack development to ensure correctly ordered testing of changes in parallel.