docs/doc/source/introduction/terms.rst

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Basic Terminology
=================

The following definitions describe key concepts and terminology that are
commonly used in the |org| community and in this documentation.

All-in-one Controller Node
  A single physical node that provides a controller function, worker function,
  and storage function.

Bare Metal
  A node running without hypervisors (for example, application workloads run
  directly on the operating system which runs directly on the hardware).

Worker
  A node within a |prod| edge cloud that is dedicated to running application
  workloads. There can be 0 to |max-workers| worker nodes in a |prod| edge cloud.

  - Runs virtual switch for realizing virtual networks.
  - Provides L3 routing and NET services.

  In a configuration running OpenStack, a worker node is labeled as 'compute'
  and may be referred to as a compute node.

Controller
  A node within a |prod| edge cloud that runs the cloud management software
  (*control plane*). There can be either one or two controller nodes in a
  |prod| edge cloud.

  - Runs cloud control functions for managing cloud resources.
  - Runs all OpenStack control functions, such as managing images, virtual
    volumes, virtual network, and virtual machines.
  - Can be part of a two-node HA control node cluster for running control
    functions either active/active or active/standby.

Data Network(s)
  Networks on which the OpenStack / Neutron provider networks are realized and
  become the VM tenant networks.

  Only worker-type and all-in-one-type nodes are required to be connected to
  the data network(s). These node types require one or more interface(s) on the
  data network(s).

Deployment Tools
  Tools that make the process of distributing, installing, and managing
  updates.

Edge Computing
  The delivery of computing capabilities to the logical extremes of a network
  in order to improve the performance, operating cost and reliability of
  applications and services. By shortening the distance between devices and the
  resources that serve them, and also reducing network hops, edge computing
  mitigates the latency and bandwidth constraints of today's Internet, ushering
  in new classes of applications.

  From `Open Glossary of Edge Computing <https://github.com/State-of-the-
  Edge/glossary/blob/master/edge-glossary.md#edge-computing>`_

Infra Network
  A deprecated optional network that was historically used for access to the
  storage cluster.

  If this optional network is used, all node types are required to be connected
  to the INFRA network.

IoT (Internet of Things)
  A system of computing devices that can operate with little/no human
  interaction.

IPMI Network
  An optional network on which Intelligent Platform Management Interface
  (IPMI) interfaces of all nodes are connected. The network must be reachable
  using L3/IP from the controller's OAM interfaces.

  You can optionally connect all node types to the |IPMI| network.

Kubernetes Cluster
  A set of machines that has a common control plane for running orchestrated
  applications.

Management Network
  A private network (that is, not connected externally), typically 10GE, used
  for the following:

  - Internal OpenStack / |prod| monitoring and control.
  - VM I/O access to a storage cluster.

  All nodes are required to be connected to the management network.

Node
  A computer that is usually a server-class system.

Node Interfaces
  All nodes' network interfaces can, in general, optionally be either:

  - Untagged single port.
  - Untagged two-port LAG and optionally split between redundant L2 switches
    running vPC (Virtual Port-Channel), also known as multichassis
    EtherChannel (MEC).
  - VLAN on either single-port ETH interface or two-port LAG interface.

|OAM| Network
  The network on which all external |prod| platform APIs are exposed,
  (that is, REST APIs, Horizon web server, |SSH|, and |SNMP|), typically 1GE.

  Only controller type nodes are required to be connected to the OAM network.

Open Source StarlingX
  A set of services that can be used to build cloud infrastructure. The source
  code of the services is available under an open source license that allows
  access and re-distribution of the codebase. The software components are
  created and maintained with an open development process through
  collaboration.

PXEBoot Network
  An optional network for controllers to boot/install other nodes over the
  network.

  By default, controllers use the management network for boot/install of other
  nodes in the OpenStack cloud. If this optional network is used, all node
  types are required to be connected to the PXEBoot network.

  A PXEBoot network is required for a variety of special case situations:

  - Cases where the management network must be IPv6:

    - IPv6 does not support PXEBoot. Therefore, you must configure an IPv4
      PXEBoot network.

  - Cases where the management network must be |VLAN| tagged:

    - Most server's BIOS do not support PXEBooting over tagged networks.
      Therefore, you must configure an untagged PXEBoot network.

  - Cases where a management network must be shared across regions but
    individual regions' controllers want to only network boot/install nodes of
    their own region:

    - You must configure separate, per-region PXEBoot networks.

|prod|
  |prod| is an open source, complete cloud infrastructure software stack
  for the edge used by the most demanding applications in industrial |IoT|,
  telecom, and other use cases. The platform creates a fusion between OpenStack
  and Kubernetes to provide a robust and flexible environment for all kinds of
  workloads, let them be containerized, virtualized or bare metal.

Storage
  A node within a |prod| edge cloud that is dedicated to providing file
  and object storage to application workloads. There can be 0 or more storage
  nodes within a |prod| edge cloud.

  - Runs CEPH distributed storage software.
  - Part of an HA multi-node CEPH storage cluster supporting a replication
    factor of two or three, journal caching, and class tiering.
  - Provides HA persistent storage for images, virtual volumes (that is, block
    storage), and object storage.

Virtualization
  The act of creating a virtual version of CPU, network or storage device.

Virtual Machines (VM)
  An instance of a node provided by software (a hypervisor), which runs within
  the host operating system and hardware.