About
Introduction to OpenShift Container Platform
Abstract
Chapter 1. OpenShift Container Platform 4.6 Documentation
Welcome to the official OpenShift Container Platform 4.6 documentation, where you can find information to help you learn about OpenShift Container Platform and start exploring its features.
To navigate the OpenShift Container Platform 4.6 documentation, you can either
- Use the left navigation bar to browse the documentation or
- Select the activity that interests you from the contents of this Welcome page
You can start with Architecture and Security and compliance. Then, see Release notes.
1.1. Cluster installer activities
As someone setting out to install an OpenShift Container Platform 4.6 cluster, this documentation helps you:
- Install a cluster on AWS: You have the most installation options when you deploy a cluster on Amazon Web Services (AWS). You can deploy clusters with default settings or custom AWS settings. You can also deploy a cluster on AWS infrastructure that you provisioned yourself. You can modify the provided AWS CloudFormation templates to meet your needs.
- Install a cluster on Azure: You can deploy clusters with default settings, custom Azure settings, or custom networking settings in Microsoft Azure. You can also provision OpenShift Container Platform into an Azure Virtual Network or use Azure Resource Manager Templates to provision your own infrastructure.
- Install a cluster on GCP: You can deploy clusters with default settings or custom GCP settings on Google Cloud Platform (GCP). You can also perform a GCP installation where you provision your own infrastructure.
- Install a cluster on VMware vSphere: You can install OpenShift Container Platform on supported versions of vSphere.
- Install a cluster on bare metal: If none of the available platform and cloud providers meet your needs, you can install OpenShift Container Platform on bare metal.
- Install an installer-provisioned cluster on bare metal: You can install OpenShift Container Platform on bare metal with an installer-provisioned architecture.
-
Create Red Hat Enterprise Linux CoreOS (RHCOS) machines on bare metal: You can install RHCOS machines using ISO or PXE in a fully live environment and configure them with kernel arguments, Ignition configs, or the
coreos-installercommand. - Install a cluster on Red Hat OpenStack Platform (RHOSP): You can install a cluster on RHOSP with customizations.
- Install a cluster on Red Hat Virtualization (RHV): You can deploy clusters on Red Hat Virtualization (RHV) with a quick install or an install with customizations.
- Install a cluster in a restricted network: If your cluster that uses user-provisioned infrastructure on AWS, GCP, vSphere, or bare metal does not have full access to the internet, you can mirror the OpenShift Container Platform installation images and install a cluster in a restricted network.
- Install a cluster in an existing network: If you use an existing Virtual Private Cloud (VPC) in AWS or GCP or an existing VNet on Azure, you can install a cluster.
- Install a private cluster: If your cluster does not require external internet access, you can install a private cluster on AWS, Azure, or GCP. Internet access is still required to access the cloud APIs and installation media.
- Check installation logs: Access installation logs to evaluate issues that occur during OpenShift Container Platform 4.6 installation.
- Access OpenShift Container Platform: Use credentials output at the end of the installation process to log in to the OpenShift Container Platform cluster from the command line or web console.
- Install Red Hat OpenShift Container Storage: You can install Red Hat OpenShift Container Storage as an Operator to provide highly integrated and simplified persistent storage management for containers.
1.2. Developer activities
Ultimately, OpenShift Container Platform is a platform for developing and deploying containerized applications. As an application developer, OpenShift Container Platform documentation helps you:
- Understand OpenShift Container Platform development: Learn the different types of containerized applications, from simple containers to advanced Kubernetes deployments and Operators.
- Work with projects: Create projects from the web console or CLI to organize and share the software you develop.
- Work with applications: Use the Developer perspective in the OpenShift Container Platform web console to easily create and deploy applications.
Use the Topology view to visually interact with your applications, monitor status, connect and group components, and modify your code base.
- Use the developer CLI tool (odo): The odo CLI tool lets developers create single or multi-component applications easily and automates deployment, build, and service route configurations. It abstracts complex Kubernetes and OpenShift Container Platform concepts, allowing developers to focus on developing their applications.
- Create CI/CD Pipelines: Pipelines are serverless, cloud-native, continuous integration and continuous deployment systems that run in isolated containers. They use standard Tekton custom resources to automate deployments and are designed for decentralized teams that work on microservices-based architecture.
- Deploy Helm charts: Helm 3 is a package manager that helps developers define, install, and update application packages on Kubernetes. A Helm chart is a packaging format that describes an application that can be deployed using the Helm CLI.
- Understand Operators: Operators are the preferred method for creating on-cluster applications for OpenShift Container Platform 4.6. Learn about the Operator Framework and how to deploy applications using installed Operators into your projects.
- Understand image builds: Choose from different build strategies (Docker, S2I, custom, and pipeline) that can include different kinds of source materials (from places like Git repositories, local binary inputs, and external artifacts). Then, follow examples of build types from basic builds to advanced builds.
- Create container images: A container image is the most basic building block in OpenShift Container Platform (and Kubernetes) applications. Defining image streams lets you gather multiple versions of an image in one place as you continue its development. S2I containers let you insert your source code into a base container that is set up to run code of a particular type (such as Ruby, Node.js, or Python).
-
Create deployments: Use
DeploymentandDeploymentConfigobjects to exert fine-grained management over applications. Use the Workloads page orocCLI to manage deployments. Learn rolling, recreate, and custom deployment strategies. - Create templates: Use existing templates or create your own templates that describe how an application is built or deployed. A template can combine images with descriptions, parameters, replicas, exposed ports and other content that defines how an application can be run or built.
- Create Operators: Operators are the preferred method for creating on-cluster applications for OpenShift Container Platform 4.6. Learn the workflow for building, testing, and deploying Operators. Then create your own Operators based on Ansible or Helm, or configure built-in Prometheus monitoring using the Operator SDK.
- REST API reference: Lists OpenShift Container Platform application programming interface endpoints.
1.3. Cluster administrator activities
Ongoing tasks on your OpenShift Container Platform 4.6 cluster include various activities for managing machines, providing services to users, and following monitoring and logging features that watch over the cluster. As a cluster administrator, this documentation helps you:
- Understand OpenShift Container Platform management: Learn about components of the OpenShift Container Platform 4.6 control plane. See how OpenShift Container Platform masters and workers are managed and updated through the Machine API and Operators.
1.3.1. Manage cluster components
- Manage machines: Manage machines in your cluster on AWS, Azure, or GCP by deploying health checks and applying autoscaling to machines.
- Manage container registries: Each OpenShift Container Platform cluster includes a built-in container registry for storing its images. You can also configure a separate Red Hat Quay registry to use with OpenShift Container Platform. The Quay.io web site provides a public container registry that stores OpenShift Container Platform containers and Operators.
- Manage users and groups: Add users and groups that have different levels of permissions to use or modify clusters.
- Manage authentication: Learn how user, group, and API authentication works in OpenShift Container Platform. OpenShift Container Platform supports multiple identity providers, including HTPasswd, Keystone, LDAP, basic authentication, request header, GitHub, GitLab, Google, and OpenID.
- Manage ingress, API server, and service certificates: OpenShift Container Platform creates certificates by default for the Ingress Operator, the API server, and for services needed by complex middleware applications that require encryption. At some point, you might need to change, add, or rotate these certificates.
- Manage networking: Networking in OpenShift Container Platform is managed by the Cluster Network Operator (CNO). The CNO uses iptables rules in kube-proxy to direct traffic between nodes and pods running on those nodes. The Multus Container Network Interface adds the capability to attach multiple network interfaces to a pod. Using network policy features, you can isolate your pods or permit selected traffic.
- Manage storage: OpenShift Container Platform allows cluster administrators to configure persistent storage using Red Hat OpenShift Container Storage, AWS Elastic Block Store, NFS, iSCSI, Container Storage Interface (CSI), and more. As needed, you can expand persistent volumes, configure dynamic provisioning, and use CSI to configure and clone persistent storage.
- Manage Operators: Lists of Red Hat, ISV, and community Operators can be reviewed by cluster administrators and installed on their clusters. Once installed, you can run, upgrade, back up or otherwise manage the Operator on your cluster (based on what the Operator is designed to do).
1.3.2. Change cluster components
- Use custom resource definitions (CRDs) to modify the cluster: Cluster features that are implemented with Operators, can be modified with CRDs. Learn to create a CRD and manage resources from CRDs.
- Set resource quotas: Choose from CPU, memory and other system resources to set quotas.
- Prune and reclaim resources: You can reclaim space by pruning unneeded Operators, groups, deployments, builds, images, registries, and cron jobs.
- Scale and tune clusters: Set cluster limits, tune nodes, scale cluster monitoring, and optimize networking, storage, and routes for your environment.
- Update a cluster: To upgrade your OpenShift Container Platform to a later version, use the Cluster Version Operator (CVO). If an update is available from the Container Platform update service, you apply that cluster update from either the web console or the CLI.
- Understanding the OpenShift Update Service: Learn about installing and managing a local OpenShift Update Service for recommending OpenShift Container Platform updates in restricted network environments.
1.3.3. Monitor the cluster
- Work with cluster logging: Learn about cluster logging and configure different cluster logging types, such as Elasticsearch, Fluentd, Kibana, and Curator.
- Monitor clusters: Learn to configure the monitoring stack. Once your monitoring is configured, use the Web UI to access monitoring dashboards. In addition to infrastructure metrics, you can also scrape and view metrics for your own services.
- Remote health monitoring: OpenShift Container Platform collects anonymized aggregated information about your cluster and reports it to Red Hat via Telemetry and the Insights Operator. This information allows Red Hat to improve OpenShift Container Platform and to react to issues that impact customers more quickly. You can view the data collected by remote health monitoring.
Chapter 2. About {oke}
As of 27 April 2020, Red Hat has decided to rename Red Hat OpenShift Container Engine to Red Hat OpenShift Kubernetes Engine in order to better communicate what value the product offering delivers.
Red Hat OpenShift Kubernetes Engine is a product offering from Red Hat that lets you use an enterprise class Kubernetes platform as a production platform for launching containers. You download and install OpenShift Kubernetes Engine the same way as OpenShift Container Platform as they are the same binary distribution, but OpenShift Kubernetes Engine offers a subset of the features that OpenShift Container Platform offers.
2.1. Similarities and differences
You can see the similarities and differences between OpenShift Kubernetes Engine and OpenShift Container Platform in the following table:
| OpenShift Kubernetes Engine | OpenShift Container Platform | ||
|---|---|---|---|
| Fully Automated Installers | Yes | Yes | |
| Over the Air Smart Upgrades | Yes | Yes | |
| Enterprise Secured Kubernetes | Yes | Yes | |
| Kubectl and oc automated command line | Yes | Yes | |
| Operator Lifecycle Manager (OLM) | Yes | Yes | |
| Administrator Web console | Yes | Yes | |
| OpenShift Virtualization | Yes | Yes | |
| User Workload Monitoring | Yes | ||
| Metering and Cost Management SaaS Service | Yes | ||
| Platform Logging | Yes | ||
| Developer Web Console | Yes | ||
| Developer Application Catalog | Yes | ||
| Source to Image and Builder Automation (Tekton) | Yes | ||
| OpenShift Service Mesh (Kiali, Jaeger, and OpenTracing) | Yes | ||
| OpenShift Serverless (Knative) | Yes | ||
| OpenShift Pipelines (Jenkins and Tekton) | Yes | ||
| Embedded Component of IBM Cloud Pak and RHT MW Bundles | Yes | ||
2.1.1. Core Kubernetes and container orchestration
OpenShift Kubernetes Engine offers full access to an enterprise-ready Kubernetes environment that is easy to install and offers an extensive compatibility test matrix with many of the software elements that you might use in your data center.
OpenShift Kubernetes Engine offers the same service level agreements, bug fixes, and common vulnerabilities and errors protection as OpenShift Container Platform. OpenShift Kubernetes Engine includes a Red Hat Enterprise Linux (RHEL) Virtual Datacenter and Red Hat Enterprise Linux CoreOS (RHCOS) entitlement that allows you to use an integrated Linux operating system with container runtime from the same technology provider.
The OpenShift Kubernetes Engine subscription is compatible with the Red Hat OpenShift support for Windows Containers subscription.
2.1.2. Enterprise-ready configurations
OpenShift Kubernetes Engine uses the same security options and default settings as the OpenShift Container Platform. Default security context constraints, pod security policies, best practice network and storage settings, service account configuration, SELinux integration, HAproxy edge routing configuration, and all other standard protections that OpenShift Container Platform offers are available in OpenShift Kubernetes Engine. OpenShift Kubernetes Engine offers full access to the integrated monitoring solution that OpenShift Container Platform uses, which is based on Prometheus and offers deep coverage and alerting for common Kubernetes issues.
OpenShift Kubernetes Engine uses the same installation and upgrade automation as OpenShift Container Platform.
2.1.3. Standard infrastructure services
With an OpenShift Kubernetes Engine subscription, you receive support for all storage plug-ins that OpenShift Container Platform supports.
In terms of networking, OpenShift Kubernetes Engine offers full and supported access to the Kubernetes Container Network Interface (CNI) and therefore allows you to use any third-party SDN that supports OpenShift Container Platform. It also allows you to use the included Open vSwitch software defined network to its fullest extent. OpenShift Kubernetes Engine allows you to take full advantage of the OVN Kubernetes overlay, Multus, and Multus plug-ins that are supported on OpenShift Container Platform. OpenShift Kubernetes Engine allows customers to use a Kubernetes Network Policy to create microsegmentation between deployed application services on the cluster.
You can also use the Route API objects that are found in OpenShift Container Platform, including its sophisticated integration with the HAproxy edge routing layer as an out of the box Kubernetes ingress controller.
2.1.4. Core user experience
OpenShift Kubernetes Engine users have full access to Kubernetes Operators, pod deployment strategies, Helm, and OpenShift Container Platform templates. OpenShift Kubernetes Engine users can use both the oc and kubectl command line interfaces. OpenShift Kubernetes Engine also offers an administrator web-based console that shows all aspects of the deployed container services and offers a container-as-a service experience. OpenShift Kubernetes Engine grants access to the Operator Life Cycle Manager that helps you control access to content on the cluster and life cycle operator-enabled services that you use. With an OpenShift Kubernetes Engine subscription, you receive access to the Kubernetes namespace, the OpenShift Project API object, and cluster-level Prometheus monitoring metrics and events.
2.1.5. Maintained and curated content
With an OpenShift Kubernetes Engine subscription, you receive access to the OpenShift Container Platform content from the Red Hat Ecosystem Catalog and Red Hat Connect ISV marketplace. You can access all maintained and curated content that the OpenShift Container Platform eco-system offers.
2.1.6. OpenShift Container Storage compatible
OpenShift Kubernetes Engine is compatible and supported with your purchase of OpenShift Container Storage.
2.1.7. Red Hat Middleware compatible
OpenShift Kubernetes Engine is compatible and supported with individual Red Hat Middleware product solutions. Red Hat Middleware Bundles that include OpenShift embedded in them only contain OpenShift Container Platform.
2.1.8. OpenShift Serverless
OpenShift Kubernetes Engine does not include OpenShift Serverless support. Please use OpenShift Container Platform for this support.
2.1.9. Quay Integration compatible
OpenShift Kubernetes Engine is compatible and supported with a Red Hat Quay purchase.
2.1.10. OpenShift Virtualization
OpenShift Kubernetes Engine includes support for the Red Hat product offerings derived from the kubevirt.io open source project.
2.1.11. Advanced cluster management
OpenShift Kubernetes Engine is compatible with your additional purchase of {rh-rhacm-first} for Kubernetes. An OpenShift Kubernetes Engine subscription does not offer a cluster-wide log aggregation solution or support Elasticsearch, Fluentd, or Kibana based logging solutions. Similarly, the chargeback features found in OpenShift Container Platform or the console.redhat.com Cost Management SaaS service are not supported with OpenShift Kubernetes Engine. Red Hat Service Mesh capabilities derived from the open source istio.io and kiali.io projects that offer OpenTracing observability for containerized services on OpenShift Container Platform are not supported in OpenShift Kubernetes Engine.
2.1.12. Advanced networking
The standard networking solutions in OpenShift Container Platform are supported with an OpenShift Kubernetes Engine subscription. OpenShift Container Platform’s Kubernetes CNI plug-in for automation of multi-tenant network segmentation between OpenShift Container Platform projects is entitled for use with OpenShift Kubernetes Engine. OpenShift Kubernetes Engine offers all the granular control of the source IP addresses that are used by application services on the cluster. Those egress IP address controls are entitled for use with OpenShift Kubernetes Engine. OpenShift Container Platform offers ingress routing to on cluster services that use non-standard ports when no public cloud provider is in use via the VIP pods found in OpenShift Container Platform. That ingress solution is supported in OpenShift Kubernetes Engine. OpenShift Kubernetes Engine users are supported for the Kubernetes ingress control object, which offers integrations with public cloud providers. Red Hat Service Mesh, which is derived from the istio.io open source project, is not supported in OpenShift Kubernetes Engine. Also, the Kourier ingress controller found in OpenShift Serverless is not supported on OpenShift Kubernetes Engine.
2.1.13. Developer experience
With OpenShift Kubernetes Engine, the following capabilities are not supported:
- The CodeReady developer experience utilities and tools, such as CodeReady Workspaces.
- OpenShift Container Platform’s pipeline feature that integrates a streamlined, Kubernetes-enabled Jenkins and Tekton experience in the user’s project space.
- The OpenShift Container Platform’s source-to-image feature, which allows you to easily deploy source code, dockerfiles, or container images across the cluster.
- Build strategies, builder pods, or Tekton for end user container deployments.
-
The
ododeveloper command line. - The developer persona in the OpenShift Container Platform web console.
2.1.14. Feature summary
The following table is a summary of the feature availability in OpenShift Kubernetes Engine and OpenShift Container Platform.
| Feature | OpenShift Kubernetes Engine | OpenShift Container Platform | Operator name |
| Fully Automated Installers (IPI) | Included | Included | N/A |
| Customizable Installers (UPI) | Included | Included | N/A |
| Disconnected Installation | Included | Included | N/A |
| Red Hat Enterprise Linux (RHEL) or Red Hat Enterprise Linux CoreOS (RHCOS) entitlement | Included | Included | N/A |
| Existing RHEL manual attach to cluster (BYO) | Included | Included | N/A |
| CRIO Runtime | Included | Included | N/A |
| Over the Air Smart Upgrades and Operating System (RHCOS) Management | Included | Included | N/A |
| Enterprise Secured Kubernetes | Included | Included | N/A |
|
Kubectl and | Included | Included | N/A |
| Auth Integrations, RBAC, SCC, Multi-Tenancy Admission Controller | Included | Included | N/A |
| Operator Lifecycle Manager (OLM) | Included | Included | N/A |
| Administrator web console | Included | Included | N/A |
| OpenShift Virtualization | Included | Included | OpenShift Virtualization Operator |
| Compliance Operator provided by Red Hat | Included | Included | Compliance Operator |
| File Integrity Operator | Included | Included | File Integrity Operator |
| Gatekeeper Operator | Not Included - Requires separate subscription | Not Included - Requires separate subscription | Gatekeeper Operator |
| Klusterlet | Not Included - Requires separate subscription | Not Included - Requires separate subscription | N/A |
| Kube Descheduler Operator provided by Red Hat | Included | Included | Kube Descheduler Operator |
| Local Storage provided by Red Hat | Included | Included | Local Storage Operator |
| Node Feature Discovery provided by Red Hat | Included | Included | Node Feature Discovery Operator |
| Performance Add-on Operator | Included | Included | Performance Add-on Operator |
| PTP Operator provided by Red Hat | Included | Included | PTP Operator |
| Service Telemetry Operator provided by Red Hat | Included | Included | Service Telemetry Operator |
| SR-IOV Network Operator | Included | Included | SR-IOV Network Operator |
| Vertical Pod Autoscaler | Included | Included | Vertical Pod Autoscaler |
| Cluster Monitoring (Prometheus) | Included | Included | Cluster Monitoring |
| Device Manager (for example, GPU) | Included | Included | N/A |
| Log Forwarding (with fluentd) | Included | Included | Red Hat OpenShift Logging Operator (for log forwarding with fluentd) |
| Telemeter and Insights Connected Experience | Included | Included | N/A |
| Feature | OpenShift Kubernetes Engine | OpenShift Container Platform | Operator name |
| OpenShift Cloud Manager SaaS Service | Included | Included | N/A |
| OVS and OVN SDN | Included | Included | N/A |
| MetalLB | Included | Included | MetalLB Operator |
| HAProxy Ingress Controller | Included | Included | N/A |
| Red Hat OpenStack Platform (RHOSP) Kuryr Integration | Included | Included | N/A |
| Ingress Cluster-wide Firewall | Included | Included | N/A |
| Egress Pod and Namespace Granular Control | Included | Included | N/A |
| Ingress Non-Standard Ports | Included | Included | N/A |
| Multus and Available Multus Plugins | Included | Included | N/A |
| Network Policies | Included | Included | N/A |
| IPv6 Single and Dual Stack | Included | Included | N/A |
| CNI Plugin ISV Compatibility | Included | Included | N/A |
| CSI Plugin ISV Compatibility | Included | Included | N/A |
| RHT and IBM middleware à la carte purchases (not included in OpenShift Container Platform or OpenShift Kubernetes Engine) | Included | Included | N/A |
| ISV or Partner Operator and Container Compatibility (not included in OpenShift Container Platform or OpenShift Kubernetes Engine) | Included | Included | N/A |
| Embedded OperatorHub | Included | Included | N/A |
| Embedded Marketplace | Included | Included | N/A |
| Quay Compatibility (not included) | Included | Included | N/A |
| RHEL Software Collections and RHT SSO Common Service (included) | Included | Included | N/A |
| Embedded Registry | Included | Included | N/A |
| Helm | Included | Included | N/A |
| User Workload Monitoring | Not Included | Included | N/A |
| Metering and Cost Management SaaS Service | Not Included | Included | N/A |
| Platform Logging | Not Included | Included | Red Hat OpenShift Logging Operator |
| OpenShift Elasticsearch Operator provided by Red Hat | Not Included | Cannot be run standalone | N/A |
| Developer Web Console | Not Included | Included | N/A |
| Developer Application Catalog | Not Included | Included | N/A |
| Source to Image and Builder Automation (Tekton) | Not Included | Included | N/A |
| OpenShift Service Mesh | Not Included | Included | OpenShift Service Mesh Operator |
| Service Binding Operator | Not Included | Included | Service Binding Operator |
| Feature | OpenShift Kubernetes Engine | OpenShift Container Platform | Operator name |
| Red Hat OpenShift Serverless | Not Included | Included | OpenShift Serverless Operator |
| Web Terminal provided by Red Hat | Not Included | Included | Web Terminal Operator |
| Jenkins Operator provided by Red Hat | Not Included | Included | Jenkins Operator |
| Red Hat OpenShift Pipelines Operator | Not Included | Included | OpenShift Pipelines Operator |
| Embedded Component of IBM Cloud Pak and RHT MW Bundles | Not Included | Included | N/A |
| Red Hat OpenShift GitOps | Not Included | Included | OpenShift GitOps |
| Red Hat CodeReady Workspaces | Not Included | Included | CodeReady Workspaces |
| Red Hat CodeReady Containers | Not Included | Included | N/A |
| Quay Bridge Operator provided by Red Hat | Not Included | Included | Quay Bridge Operator |
| Quay Container Security provided by Red Hat | Not Included | Included | Quay Operator |
| Red Hat OpenShift distributed tracing platform | Not Included | Included | Red Hat OpenShift distributed tracing platform Operator |
| Red Hat OpenShift Kiali | Not Included | Included | Kiali Operator |
| Metering provided by Red Hat (deprecated) | Not Included | Included | N/A |
| Migration Toolkit for Containers Operator | Not Included | Included | Migration Toolkit for Containers Operator |
| Cost management for OpenShift | Not included | Included | N/A |
| Red Hat JBoss Web Server | Not included | Included | JWS Operator |
| Red Hat Build of Quarkus | Not included | Included | N/A |
| Kourier Ingress Controller | Not included | Included | N/A |
| RHT Middleware Bundles Sub Compatibility (not included in OpenShift Container Platform) | Not included | Included | N/A |
| IBM Cloud Pak Sub Compatibility (not included in OpenShift Container Platform) | Not included | Included | N/A |
|
OpenShift Do ( | Not included | Included | N/A |
| Source to Image and Tekton Builders | Not included | Included | N/A |
| OpenShift Serverless FaaS | Not included | Included | N/A |
| IDE Integrations | Not included | Included | N/A |
| Windows Machine Config Operator | Community Windows Machine Config Operator included - no subscription required | Red Hat Windows Machine Config Operator included - Requires separate subscription | Windows Machine Config Operator |
| Red Hat Quay | Not Included - Requires separate subscription | Not Included - Requires separate subscription | Quay Operator |
| Red Hat Advanced Cluster Management | Not Included - Requires separate subscription | Not Included - Requires separate subscription | Advanced Cluster Management for Kubernetes |
| Red Hat Advanced Cluster Security | Not Included - Requires separate subscription | Not Included - Requires separate subscription | N/A |
| OpenShift Container Storage | Not Included - Requires separate subscription | Not Included - Requires separate subscription | OpenShift Container Storage |
| Feature | OpenShift Kubernetes Engine | OpenShift Container Platform | Operator name |
| Ansible Automation Platform Resource Operator | Not Included - Requires separate subscription | Not Included - Requires separate subscription | Ansible Automation Platform Resource Operator |
| Business Automation provided by Red Hat | Not Included - Requires separate subscription | Not Included - Requires separate subscription | Business Automation Operator |
| Data Grid provided by Red Hat | Not Included - Requires separate subscription | Not Included - Requires separate subscription | Data Grid Operator |
| Red Hat Integration provided by Red Hat | Not Included - Requires separate subscription | Not Included - Requires separate subscription | Red Hat Integration Operator |
| Red Hat Integration - 3Scale provided by Red Hat | Not Included - Requires separate subscription | Not Included - Requires separate subscription | 3scale |
| Red Hat Integration - 3Scale APICast gateway provided by Red Hat | Not Included - Requires separate subscription | Not Included - Requires separate subscription | 3scale APIcast |
| Red Hat Integration - AMQ Broker | Not Included - Requires separate subscription | Not Included - Requires separate subscription | AMQ Broker |
| Red Hat Integration - AMQ Broker LTS | Not Included - Requires separate subscription | Not Included - Requires separate subscription | |
| Red Hat Integration - AMQ Interconnect | Not Included - Requires separate subscription | Not Included - Requires separate subscription | AMQ Interconnect |
| Red Hat Integration - AMQ Online | Not Included - Requires separate subscription | Not Included - Requires separate subscription | |
| Red Hat Integration - AMQ Streams | Not Included - Requires separate subscription | Not Included - Requires separate subscription | AMQ Streams |
| Red Hat Integration - Camel K | Not Included - Requires separate subscription | Not Included - Requires separate subscription | Camel K |
| Red Hat Integration - Fuse Console | Not Included - Requires separate subscription | Not Included - Requires separate subscription | Fuse Console |
| Red Hat Integration - Fuse Online | Not Included - Requires separate subscription | Not Included - Requires separate subscription | Fuse Online |
| Red Hat Integration - Service Registry Operator | Not Included - Requires separate subscription | Not Included - Requires separate subscription | Service Registry |
| API Designer provided by Red Hat | Not Included - Requires separate subscription | Not Included - Requires separate subscription | API Designer |
| JBoss EAP provided by Red Hat | Not Included - Requires separate subscription | Not Included - Requires separate subscription | JBoss EAP |
| JBoss Web Server provided by Red Hat | Not Included - Requires separate subscription | Not Included - Requires separate subscription | JBoss Web Server |
| Smart Gateway Operator | Not Included - Requires separate subscription | Not Included - Requires separate subscription | Smart Gateway Operator |
2.2. Subscription Limitations
OpenShift Kubernetes Engine is a subscription offering that provides OpenShift Container Platform with a limited set of supported features at a lower list price. OpenShift Kubernetes Engine and OpenShift Container Platform are the same product and, therefore, all software and features are delivered in both. There is only one download, OpenShift Container Platform. OpenShift Kubernetes Engine uses the OpenShift Container Platform documentation and support services and bug errata for this reason.
Chapter 3. Kubernetes overview
Kubernetes is an open source container orchestration tool developed by Google. You can run and manage container-based workloads by using Kubernetes. The most common Kubernetes use case is to deploy an array of interconnected microservices, building an application in a cloud native way. You can create Kubernetes clusters that can span hosts across on-premise, public, private, or hybrid clouds.
Traditionally, applications were deployed on top of a single operating system. With virtualization, you can split the physical host into several virtual hosts. Working on virtual instances on shared resources is not optimal for efficiency and scalability. Because a virtual machine (VM) consumes as many resources as a physical machine, providing resources to a VM such as CPU, RAM, and storage can be expensive. Also, you might see your application degrading in performance due to virtual instance usage on shared resources.
Figure 3.1. Evolution of container technologies for classical deployments
To solve this problem, you can use containerization technologies that segregate applications in a containerized environment. Similar to a VM, a container has its own filesystem, vCPU, memory, process space, dependencies, and more. Containers are decoupled from the underlying infrastructure, and are portable across clouds and OS distributions. Containers are inherently much lighter than a fully-featured OS, and are lightweight isolated processes that run on the operating system kernel. VMs are slower to boot, and are an abstraction of physical hardware. VMs run on a single machine with the help of a hypervisor.
You can perform the following actions by using Kubernetes:
- Sharing resources
- Orchestrating containers across multiple hosts
- Installing new hardware configurations
- Running health checks and self-healing applications
- Scaling containerized applications
3.1. Kubernetes components
| Component | Purpose |
|---|---|
|
| Runs on every node in the cluster and maintains the network traffic between the Kubernetes resources. |
|
| Governs the state of the cluster. |
|
| Allocates pods to nodes. |
|
| Stores cluster data. |
|
| Validates and configures data for the API objects. |
|
| Runs on nodes and reads the container manifests. Ensures that the defined containers have started and are running. |
|
|
Allows you to define how you want to run workloads. Use the |
| Node | Node is a physical machine or a VM in a Kubernetes cluster. The control plane manages every node and schedules pods across the nodes in the Kubernetes cluster. |
| container runtime | container runtime runs containers on a host operating system. You must install a container runtime on each node so that pods can run on the node. |
| Persistent storage | Stores the data even after the device is shut down. Kubernetes uses persistent volumes to store the application data. |
|
| Stores and accesses the container images. |
| Pod | The pod is the smallest logical unit in Kubernetes. A pod contains one or more containers to run in a worker node. |
3.2. Kubernetes resources
A custom resource is an extension of the Kubernetes API. You can customize Kubernetes clusters by using custom resources. Operators are software extensions which manage applications and their components with the help of custom resources. Kubernetes uses a declarative model when you want a fixed desired result while dealing with cluster resources. By using Operators, Kubernetes defines its states in a declarative way. You can modify the Kubernetes cluster resources by using imperative commands. An Operator acts as a control loop which continuously compares the desired state of resources with the actual state of resources and puts actions in place to bring reality in line with the desired state.
Figure 3.2. Kubernetes cluster overview
| Resource | Purpose |
|---|---|
| Service | Kubernetes uses services to expose a running application on a set of pods. |
|
|
Kubernetes uses the |
| Deployment | A resource object that maintains the life cycle of an application. |
Kubernetes is a core component of an OpenShift Container Platform. You can use OpenShift Container Platform for developing and running containerized applications. With its foundation in Kubernetes, the OpenShift Container Platform incorporates the same technology that serves as the engine for massive telecommunications, streaming video, gaming, banking, and other applications. You can extend your containerized applications beyond a single cloud to on-premise and multi-cloud environments by using the OpenShift Container Platform.
Figure 3.3. Architecture of Kubernetes
A cluster is a single computational unit consisting of multiple nodes in a cloud environment. A Kubernetes cluster includes a control plane and worker nodes. You can run Kubernetes containers across various machines and environments. The control plane node controls and maintains the state of a cluster. You can run the Kubernetes application by using worker nodes. You can use the Kubernetes namespace to differentiate cluster resources in a cluster. Namespace scoping is applicable for resource objects, such as deployment, service, and pods. You cannot use namespace for cluster-wide resource objects such as storage class, nodes, and persistent volumes.
3.3. Kubernetes conceptual guidelines
Before getting started with the OpenShift Container Platform, consider these conceptual guidelines of Kubernetes:
- Start with one or more worker nodes to run the container workloads.
- Manage the deployment of those workloads from one or more control plane nodes.
- Wrap containers in a deployment unit called a pod. By using pods provides extra metadata with the container and offers the ability to group several containers in a single deployment entity.
-
Create special kinds of assets. For example, services are represented by a set of pods and a policy that defines how they are accessed. This policy allows containers to connect to the services that they need even if they do not have the specific IP addresses for the services. Replication controllers are another special asset that indicates how many pod replicas are required to run at a time. You can use this capability to automatically scale your application to adapt to its current demand. The API to OpenShift Container Platform cluster is 100% Kubernetes. Nothing changes between a container running on any other Kubernetes and running on OpenShift Container Platform. No changes to the application. OpenShift Container Platform brings added-value features to provide enterprise-ready enhancements to Kubernetes. OpenShift Container Platform CLI tool (
oc) is compatible withkubectl. While the Kubernetes API is 100% accessible within OpenShift Container Platform, thekubectlcommand-line lacks many features that could make it more user-friendly. OpenShift Container Platform offers a set of features and command-line tool likeoc. Although Kubernetes excels at managing your applications, it does not specify or manage platform-level requirements or deployment processes. Powerful and flexible platform management tools and processes are important benefits that OpenShift Container Platform offers. You must add authentication, networking, security, monitoring, and logs management to your containerization platform.
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