User Glossary

IaaS

Infrastructure as a Service. A service that can provide virtual machines on demand.

OpenStack

An open source IaaS platform that controls and provisions a large pool of compute, storage, and networking resources. It is made up of various component services some of which are listed of below.

Flavour

A flavour specifies the compute, memory, and storage capacity of Nova computing instances. They represent the available hardware configurations for new VMs.

Image

A virtual machine image is a file that contains a virtual disk containing a bootable operating system.

Project

In the context of OpenStack, a project is a group of zero or more users and is used to associate various permissions such as the images users have access to.

Volume

A block of storage that may be attached and detached from VMs similar to a USB drive. These may only be attached to one VM at a time.

Cluster

A group of resources (Nova instances, Neutron networks, security groups etc) combined to function as one system.

Key Pair

A combination of a public key used to encrypt data and a private key used to decrypt data. Typically used in the context of using SSH to connect to a remote machine.

Floating IP

A static public IP address that is externally routable and is therefore accessible from outside of STFC and its VPN.

Load Balancer

Distributes incoming network traffic across multiple machines reducing the load on each individual one. These can be created using OpenStack Octavia.

Docker

An open platform for developing, shipping, and running applications in a loosely isolated environment called a container. These contain everything the application needs to run making them highly portable.

More info: https://www.docker.com/resources/what-container/

Kubernetes

An open source container orchestration engine for automating deployment, scaling and management of containerised applications typically using Docker. This also provides load balancing and can be very useful for the deployment of applications to many machines at once enabling scaling and redundancy.

More info: https://kubernetes.io/

Object Storage

A storage architecture that manages data as objects containing both data and metadata along with a unique identifier. Particularly useful for storing large amounts of unstructured data.

More info: https://www.redhat.com/en/topics/data-storage/file-block-object-storage

Nova

The compute component of OpenStack. This provides a way of provisioning compute instances e.g. VMs.

More info: https://docs.openstack.org/nova/latest/

Placement

An OpenStack component which tracks available resources on the platform, mainly used by Nova where it assists in choosing which resources to allocate to new VMs.

More info: https://docs.openstack.org/placement/latest/

Neutron

The networking OpenStack component responsible for provisioning the virtual or physical networks that compute instances connect to.

More info: https://docs.openstack.org/neutron/latest/

Keystone

The OpenStack identity and service catalogue component. This is responsible for the authentication of users and determines what they have access to.

More info: https://docs.openstack.org/keystone/latest/

Glance

The OpenStack image store. This provides services and associated libraries to store, browse, share, distribute and manage bootable disk images for VMs as well as metadata and other data used when initialising compute resources.

More info: https://docs.openstack.org/glance/latest/#metadata-definitions

Cinder

The OpenStack persistent block storage component. This provides volumes of storage to Nova VMs.

More info: https://docs.openstack.org/cinder/latest/

Heat

The OpenStack orchestration service. This can be used deploy whole services with a single template.

More info: https://docs.openstack.org/heat/latest/

Gnocchi

The OpenStack data collection service. This stores and indexes time series data from Nova, Neutron, Cinder and Ceilometer.

More info: https://wiki.openstack.org/wiki/Gnocchi

Aodh

The OpenStack alarming service. This provides the ability to trigger actions based on defined conditions using metric or event data obtained through the Gnocchi and Ceilometer components.

More info: https://docs.openstack.org/aodh/latest/

Ceilometer

An OpenStack data collector service that feeds into Gnocchi and Aodh.

More info: https://docs.openstack.org/ceilometer/latest/

Magnum

The OpenStack container orchestration as a service component. Used for providing Kubernetes.

More info: https://docs.openstack.org/magnum/latest/user/

Octavia

The OpenStack Loadbalancer as a service component. This can be used to manage a fleet of VMs, containers or bare metal servers and can start up more on demand ensuring the scalability of services.

More info: https://docs.openstack.org/octavia/latest/reference/introduction.html