Basic Terminology

The following definitions describe key concepts and terminology that are commonly used in the StarlingX 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 Kubelet or hypervisors (for example, application workloads run directly on the operating system which runs directly on the hardware).


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

  • Runs cloud control functions for managing cloud resources.

  • Runs all Kubernetes control functions such as kube-apiserver, kube-controller-manager and kube-schedule

  • 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 attached to pci-passthrough and/or sriov interfaces that are made available to hosted containers or hosted VMs for pci-passthrough and/or SR-IOV interfaces.

Networks attached to data interfaces of the OpenStack vSwitch, on which the OpenStack / Neutron provider networks are realized and become the VM tenant networks.

Only worker-type and all-in-one-type nodes, which host end-user containers and/or VMs would have data network(s) attached.

In the case of openstack-compute labelled worker nodes, a data network MUST be attached to at lease one ‘data’ (vSwitch) interface.

Deployment Tools

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


The process of moving from a higher version or a newer release of a software, firmware, or operating system to a lower version or an older release.

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

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 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 StarlingX Infrastructure management monitoring and control

  • in the case of openstack, it is also used by VM I/O access to virtualized disks in Ceph Storage Cluster

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


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 StarlingX 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.


A system state checks intended to confirm the system health for an impending operation. This check can be performed at any time prior to the system operation execution, but is intended to be executed just prior to confirming that it can be scheduled before actually attempting the operation.


New deployments for a system that is installed in the factory. Preinstallation also refers to software media that is installed alongside the existing deployment in preparation for an upgrade.


System software media is prepopulated on the system in preparation for an impending operation. Prestaging is currently supported for installation and upgrade operation.

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.


Bringing back a system or data from a backup or a previously saved state. For StarlingX, Restore can be used for current release (N) or (N-1).


The process of reverting changes made to a system or database to a previous state. For StarlingX, Rollback is a capability that is supported during an upgrade or update.

Shared NIC

A single physical port that can be shared by two or more system networks (oam, mgmt., cluster-host, pxeboot and data) For more information, see SRIOV Port Sharing.


StarlingX 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, including containerized, virtualized or bare metal.


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

Virtual Machines (VM)

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


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


A node within a StarlingX edge cloud that is dedicated to running application workloads. There can be 0 to 99 worker nodes in a StarlingX edge cloud.

In a configuration running OpenStack, a worker node:

  • is labeled as ‘compute’

  • may be referred to as a compute node.

  • runs virtual switch for realizing virtual networks.

  • provides L3 routing and NET services.