Architecture overview

A set of roles that dictate how users, applications, and entities within a cluster interacts with one another. An access policy increases cluster security.

Admission plugins enforce security policies, resource limitations, or configuration requirements.

To control access to an OKD cluster, a cluster administrator can configure user authentication and ensure only approved users access the cluster. To interact with an OKD cluster, you must authenticate to the OKD API. You can authenticate by providing an OAuth access token or an X.509 client certificate in your requests to the OKD API.

A temporary machine that runs minimal Kubernetes and deploys the OKD control plane.

A resource requests a denoted signer to sign a certificate. This request might get approved or denied.

An Operator that checks with the OKD Update Service to see the valid updates and update paths based on current component versions and information in the graph.

Nodes that are responsible for executing workloads for cluster users. Compute nodes are also known as worker nodes.

A situation where the configuration on a node does not match what the machine config specifies.

Lightweight and executable images that consist software and all its dependencies. Because containers virtualize the operating system, you can run containers anywhere, from a data center to a public or private cloud to your local host.

Software that automates the deployment, management, scaling, and networking of containers.

Applications that are packaged and deployed in containers.

Partitions sets of processes into groups to manage and limit the resources processes consume.

A container orchestration layer that exposes the API and interfaces to define, deploy, and manage the life cycle of containers. Control planes are also known as control plane machines.

A Kubernetes native container runtime implementation that integrates with the operating system to deliver an efficient Kubernetes experience.

A Kubernetes resource object that maintains the life cycle of an application.

A text file that contains the user commands to perform on a terminal to assemble the image.

A OKD feature that enables hosting a control plane on the OKD cluster from its data plane and workers. This model performs following actions:

deployments that deliver a consistent platform across bare metal, virtual, private, and public cloud environments. This offers speed, agility, and portability.

A utility that FCOS uses to manipulate disks during initial configuration. It completes common disk tasks, including partitioning disks, formatting partitions, writing files, and configuring users.

The installation program deploys and configures the infrastructure that the cluster runs on.

A primary node agent that runs on each node in the cluster to ensure that containers are running in a pod.

Specifications of a Kubernetes API object in a JSON or YAML format. A configuration file can include deployments, config maps, secrets, daemon sets.

A daemon that regularly checks the nodes for configuration drift.

An Operator that applies the new configuration to your cluster machines.

A group of machines, such as control plane components or user workloads, that are based on the resources that they handle.

Additional information about cluster deployment artifacts.

An approach to writing software. Applications can be separated into the smallest components, independent from each other by using microservices.

A registry that holds the mirror of OKD images.

Applications that are self-contained, built, and packaged as a single piece.

A namespace isolates specific system resources that are visible to all processes. Inside a namespace, only processes that are members of that namespace can see those resources.

Network information of OKD cluster.

A worker machine in the OKD cluster. A node is either a virtual machine (VM) or a physical machine.

For clusters with internet access, Fedora provides over-the-air updates by using an OKD update service as a hosted service located behind public APIs.

A command line tool to run OKD commands on the terminal.

A managed Fedora OKD offering on Amazon Web Services (AWS) and Google Cloud Platform (GCP). OpenShift Dedicated focuses on building and scaling applications.

A registry provided by OKD to manage images.

The preferred method of packaging, deploying, and managing a Kubernetes application in an OKD cluster. An Operator takes human operational knowledge and encodes it into software that is packaged and shared with customers.

A platform that contains various OKD Operators to install.

OLM helps you to install, update, and manage the lifecycle of Kubernetes native applications. OLM is an open source toolkit designed to manage Operators in an effective, automated, and scalable way.

An upgrade system for Linux-based operating systems that performs atomic upgrades of complete file system trees. OSTree tracks meaningful changes to the file system tree using an addressable object store, and is designed to complement existing package management systems.

The OKD Update Service (OSUS) provides over-the-air updates to OKD, including Fedora CoreOS (FCOS).

One or more containers with shared resources, such as volume and IP addresses, running in your OKD cluster. A pod is the smallest compute unit defined, deployed, and managed.

OKD can use any server implementing the container image registry API as a source of the image which allows the developers to push and pull their private container images.

OKD can use any server implementing the container image registry API as a source of the image which allows the developers to push and pull their public container images.

A managed service where you can install, modify, operate, and upgrade your OKD clusters.

A Quay.io container registry that serves most of the container images and Operators to OKD clusters.

An asset that indicates how many pod replicas are required to run at a time.

A key security control to ensure that cluster users and workloads have only access to resources required to execute their roles.

Routes expose a service to allow for network access to pods from users and applications outside the OKD instance.

The increasing or decreasing of resource capacity.

A service exposes a running application on a set of pods.

An image created based on the programming language of the application source code in OKD to deploy applications.

OKD supports many types of storage, both for on-premise and cloud providers. You can manage container storage for persistent and non-persistent data in an OKD cluster.

A component to collect information such as size, health, and status of OKD.

A template describes a set of objects that can be parameterized and processed to produce a list of objects for creation by OKD.

You can install OKD on the infrastructure that you provide. You can use the installation program to generate the assets required to provision the cluster infrastructure, create the cluster infrastructure, and then deploy the cluster to the infrastructure that you provided.

A user interface (UI) to manage OKD.

Nodes that are responsible for executing workloads for cluster users. Worker nodes are also known as compute nodes.