KaaS Glossary

This glossary describes the most commonly-used terms and descriptions in the Rackspace KaaS offering.




A Kubernetes API object that manages groups of Pods and ensures that all cluster nodes run a copy of a Pod. When Kubernetes adds a node to a cluster, it also automatically adds Pods to the node. For more information, see DaemonSet in the Kubernetes documentation.


A Kubernetes API object that manages creation and updates of Kubernetes Pods. Deployment definition is stored in a configuration file and describes the desired state. For more information, see Deployments in the Kuberentes documentation.


Elasticsearch, Fluentd, Kibana (EFK) stack

A logging and analytics solution that collects information about your cluster and visualizes it in a user-friendly web-interface.



A web-based user interface that visualizes Prometheus data.



A Kubernetes Job object that is responsible for executing a task, such as scheduling a Pod until its successful completion. After that, the job is considered completed. A Kubernetes job is not responsible for maintaining the pods in the desired state. For more information, see Jobs in the Kubernetes documentation.


KaaS Control Panel

The KaaS web user interface that enables Kubernetes objects and managed services management.


An open-source container orchestrator that enables cloud administrators to deploy and manage clusters.


A Rackspace tool that installs, configures, and enables life cycle management of a Kubernetes cluster in a cloud provider environment that is supported by Rackspace, such as RPCO, RPCR, and so on.

Kubernetes cluster

A highly-available infrastructure for Linux container management. Do not use Kubernetes environment.

Kubernetes node

A node that runs Kubernetes application workloads, also known as a worker node. By default, KaaS deploys three worker nodes. You can increase the number of nodes as needed. For more information, see Nodes.

Kubernetes objects

An entity that describes a desired state of the Kubernetes cluster. Basic Kubernetes objects include pods, services, volumes, and namespaces. For more information, see Kubernetes Objects in the Kubernetes documentation.


Monitoring as a Service (MaaS)

Rackspace monitoring software for Kubernetes clusters. Do not to confuse with MAAS.

Managed services

A set of services provided by Rackspace in addition to upstream Kubernetes functionality. The KaaS managed services include the KaaS Control Panel, monitoring, logging, disaster recovery, a private Docker image registry, networking, and storage.



A Kubernetes object that enables resource and user management in large Kubernetes clusters. Namespaces provide a logical isolation layer on top of a physical cluster. By default, KaaS deploys the following namespaces:

  • default
  • kube-system
  • monitoring
  • rackspace-system

The rackspace-system and kube-system namespaces in Kubernetes are used for managed services. Do not modify any resources in these namespaces.

For more information about namespaces, see Namespaces.



Persistent volume

A Kubernetes resource that provides storage provisioned by an administrator. For more information, see Persistent Volumes in the Kubernetes documentation.


A Kubernetes object that represents a group of Linux containers that share the same network and configuration parameters. For more information, see Pods.


A monitoring system that collects information about your Kubernetes cluster resource utilization and health. KaaS provides two instances of Prometheus. One instance monitors the Kubernetes cluster itself and is for Rackspace support engineers only. The other instance is for Kubernetes applications and is available to customers.

Provider or cloud provider

An underlying cloud platform on which a Kubernetes cluster is deployed. For example, OpenStack.


Rackspace Kubernetes-as-a-Service (KaaS)

Rackspace’s managed Kubernetes offering that enables system administrators to run containerized applications on top of a cloud environment of choice, as well as provides managed services functionality, such as logging, monitoring, disaster recovery, a private Docker registry, and so on.

Rackspace Private Cloud Powered by OpenStack (RPCO)

A Rackspace cloud offering that provides an OpenStack environment in a Rackspace or customer data center.

Rackspace Private Cloud Powered by Red Hat(RPCR)

A Rackspace cloud offering that provides a Red Hat OpenStack Platform (OSP) environment in a Rackspace or customer data center.


A Kubernetes controller that determines the number of pod replicas to run. For more information, see ReplicaSet in the Kubernetes documentation.

RPCO environment

An OpenStack environment deployed by using RPCO. Do not use “RPCO cluster”.

RPCR environment

A Red Hat OSP environment deployed by using RPCR. Do not use “RPCR cluster”.



In the Kubernetes terminology, a service is an object that defines a set of pods and a policy to access them. The concept of a Kubernetes service is different from the OpenStack service. For more information, see Services in the Kubernetes documentation.


A Kubernetes API object that manages stateful applications. For more information, see StatefulSets in the Kubernetes documentation.



An open-source software platform that is part of the KaaS solution. Terraform enables planning and automates the deployment of Kubernetes clusters.


A distribution of Kubernetes that provides simplified deployment and architecture for Kubernetes infrastructures. Tectonic is a part of the KaaS offering.



In the Kubernetes terminology, a volume is a directory to which containers in a pod have access. A Kubernetes volume’s lifespan is finite because a volume exists as long as the pod exists. For more information, see Volumes in the Kubernetes documentation.