Chapter 1. About the Assisted Installer
Chapter 1. About the Assisted Installer The Assisted Installer for Red Hat OpenShift Container Platform is a user-friendly installation solution offered on the Red Hat Hybrid Cloud Console . The Assisted Installer supports various deployment platforms with a focus on bare metal, Nutanix, vSphere, and Oracle Cloud Infrastructure. The Assisted Installer also supports various CPU architectures, including x86_64, s390x (IBM Z(R)), arm64, and ppc64le (IBM Power(R)). You can install OpenShift Container Platform on premises in a connected environment, with an optional HTTP/S proxy, for the following platforms: Highly available OpenShift Container Platform or single-node OpenShift cluster OpenShift Container Platform on bare metal or vSphere with full platform integration, or other virtualization platforms without integration Optionally, OpenShift Virtualization and Red Hat OpenShift Data Foundation 1.1. Features The Assisted Installer provides installation functionality as a service. This software-as-a-service (SaaS) approach has the following features: Web interface You can install your cluster by using the Hybrid Cloud Console instead of creating installation configuration files manually. No bootstrap node You do not need a bootstrap node because the bootstrapping process runs on a node within the cluster. Streamlined installation workflow You do not need in-depth knowledge of OpenShift Container Platform to deploy a cluster. The Assisted Installer provides reasonable default configurations. You do not need to run the OpenShift Container Platform installer locally. You have access to the latest Assisted Installer for the latest tested z-stream releases. Advanced networking options The Assisted Installer supports IPv4 and dual stack networking with OVN only, NMState-based static IP addressing, and an HTTP/S proxy. OVN is the default Container Network Interface (CNI) for OpenShift Container Platform 4.12 and later. SDN is supported up to OpenShift Container Platform 4.14. SDN supports IPv4 only. Preinstallation validation Before installing, the Assisted Installer checks the following configurations: Network connectivity Network bandwidth Connectivity to the registry Upstream DNS resolution of the domain name Time synchronization between cluster nodes Cluster node hardware Installation configuration parameters REST API You can automate the installation process by using the Assisted Installer REST API. 1.2. Customizing your installation by using Operators You can customize your deployment by selecting one or more Operators, either during the installation or afterward. Operators are used to package, deploy, and manage services and applications. This section presents the supported Assisted Installer Operators, together with their prerequisites and limitations. Important The additional requirements specified below apply to each Operator individually. If you select more than one Operator, or if the Assisted Installer automatically selects an Operator due to dependencies, the total required resources is the sum of the resource requirements for each Operator. For instructions on installing and modifying the Assisted Installer Operators, see the following sections: Installing Operators by using the web console . Installing Operators by using the API . Modifying Operators by using the API . 1.2.1. OpenShift Virtualization You can deploy OpenShift Virtualization to perform the following tasks: Create and manage Linux and Windows virtual machines (VMs). Run pod and VM workloads alongside each other in a cluster. Connect to VMs through a variety of consoles and CLI tools. Import and clone existing VMs. Manage network interface controllers and storage drives attached to VMs. Live migrate VMs between nodes. Prerequisites Requires enabled CPU virtualization support in the firmware on all nodes. Each worker node requires an additional 360 MiB of memory and 2 CPU cores. Each control plane node requires an additional 150 MiB of memory and 4 CPU cores. Requires Red Hat OpenShift Data Foundation (recommended for creating additional on-premise clusters), Logical Volume Manager Storage, or another persistent storage service. Important Deploying OpenShift Virtualization without Red Hat OpenShift Data Foundation results in the following scenarios: Multi-node cluster: No storage is configured. You must configure storage after the OpenShift Data Foundation configuration. Single-node OpenShift: Logical Volume Manager Storage (LVM Storage) is installed. You must review the prerequisites to ensure that your environment has sufficient additional resources for OpenShift Virtualization. Additional resources OpenShift Virtualization product overview . Getting started with OpenShift Virtualization . 1.2.2. Migration Toolkit for Virtualization When creating a new OpenShift cluster in the Assisted Installer, you can enable the Migration Toolkit for Virtualization (MTV) Operator. The Migration Toolkit for Virtualization Operator allows you to migrate virtual machines at scale to Red Hat OpenShift Virtualization from the following source providers: VMware vSphere Red Hat Virtualization (RHV) Red Hat OpenShift Virtualization OpenStack You can migrate to a local or a remote OpenShift Virtualization cluster. When you select the Migration Toolkit for Virtualization Operator, the Assisted Installer automatically activates the OpenShift Virtualization Operator. For a Single-node OpenShift installation, the Assisted Installer also activates the LVM Storage Operator. Prerequisites Requires OpenShift Container Platform version 4.14 or later. Requires an x86_64 CPU architecture. Requires an additional 1024 MiB of memory and 1 CPU core for each control plane node and worker node. Requires the additional resources specified for the OpenShift Virtualization Operator, installed together with OpenShift Virtualization. For details, see the prerequisites in the 'OpenShift Virtualization Operator' section. Post-installation steps After completing the installation, the Migration menu appears in the navigation pane of the Red Hat OpenShift web console. The Migration menu provides access to the Migration Toolkit for Virtualization. Use the toolkit to create and execute a migration plan with the relevant source and destination providers. For details, see either of the following chapters in the Migration Toolkit for Virtualization Guide: Migrating virtual machines by using the OpenShift Container Platform web console . Migrating virtual machines from the command line . 1.2.3. Multicluster engine for Kubernetes You can deploy the multicluster engine for Kubernetes to perform the following tasks in a large, multi-cluster environment: Provision and manage additional Kubernetes clusters from your initial cluster. Use hosted control planes to reduce management costs and optimize cluster deployment by decoupling the control and data planes. Use GitOps Zero Touch Provisioning to manage remote edge sites at scale. You can deploy the multicluster engine with OpenShift Data Foundation on all OpenShift Container Platform clusters. Prerequisites Each worker node requires an additional 16384 MiB of memory and 4 CPU cores. Each control plane node requires an additional 16384 MiB of memory and 4 CPU cores. Requires OpenShift Data Foundation (recommended for creating additional on-premise clusters), LVM Storage, or another persistent storage service. Important Deploying multicluster engine without OpenShift Data Foundation results in the following scenarios: Multi-node cluster: No storage is configured. You must configure storage after the installation process. Single-node OpenShift: LVM Storage is installed. You must review the prerequisites to ensure that your environment has sufficient additional resources for the multicluster engine. Prerequisites About the multicluster engine Operator . Red Hat OpenShift Cluster Manager documentation 1.2.4. Logical Volume Manager Storage You can use LVM Storage to dynamically provision block storage on a limited resources cluster. Prerequisites Requires at least 1 non-boot drive per host. Requires 100 MiB of additional RAM. Requires 1 additional CPU core for each non-boot drive. Additional resources Persistent storage using Logical Volume Manager Storage . Logical Volume Manager Storage documentation 1.2.5. Red Hat OpenShift Data Foundation You can use OpenShift Data Foundation for file, block, and object storage. This storage option is recommended for all OpenShift Container Platform clusters. OpenShift Data Foundation requires a separate subscription. Prerequisites There are at least 3 compute (workers) nodes, each with 19 additional GiB of memory and 8 additional CPU cores. There are at least 2 drives per compute node. For each drive, there is an additional 5 GB of RAM. You comply to the additional requirements specified here: Planning your deployment . Additional resources OpenShift Data Foundation datasheet . OpenShift Data Foundation documentation . 1.2.6. OpenShift Artificial Intelligence (AI) Red Hat(R) OpenShift(R) Artificial Intelligence (AI) is a flexible, scalable artificial intelligence (AI) and machine learning (ML) platform that enables enterprises to create and deliver AI-enabled applications at scale across hybrid cloud environments. Red Hat(R) OpenShift(R) AI enables the following functionality: Data acquisition and preparation. Model training and fine-tuning. Model serving and model monitoring. Hardware acceleration. The OpenShift AI Operator enables you to install Red Hat(R) OpenShift(R) AI on your OpenShift Container Platform cluster. From OpenShift Container Platform version 4.17 and later, you can use the Assisted Installer to deploy the OpenShift AI Operator to your cluster during the installation. For the developer preview, installing the OpenShift AI Operator automatically installs the following Operators: Red Hat OpenShift Data Foundation (in this section) Node Feature Discovery Operator Nvidia GPU Operator OpenShift Container Platform Pipelines Operator OpenShift Container Platform Service Mesh Operator OpenShift Container Platform Serverless Operator Authorino (Kubernetes) Important The integration of the OpenShift AI Operator into the Assisted Installer is a Developer Preview feature only. Developer Preview features are not supported by Red Hat in any way and are not functionally complete or production-ready. Do not use Developer Preview features for production or business-critical workloads. Developer Preview features provide early access to upcoming product features in advance of their possible inclusion in a Red Hat product offering, enabling customers to test functionality and provide feedback during the development process. These features might not have any documentation, are subject to change or removal at any time, and testing is limited. Red Hat might provide ways to submit feedback on Developer Preview features without an associated SLA. Prerequisites You are installing OpenShift Container Platform version 4.17 or later. For the OpenShift AI Operator, you meet the following miminum requirements: There are at least 2 compute (worker) nodes, each with 32 additional GiB of memory and 8 additional CPU cores. There is at least 1 supported GPU. Currently only NVIDIA GPUs are supported. Nodes that have NVIDIA GPUs installed have Secure Boot disabled. For the dependent OpenShift Data Foundation Operator, you meet the minimum additional requirements specified for that Operator in this section. You meet the additional requirements specified here: Requirements for OpenShift AI . Additional resources Red Hat(R) OpenShift(R) AI 1.2.7. Additional resources Working with Operators in OpenShift Container Platform . Introduction to hosted control planes . Configure and deploy OpenShift Container Platform clusters at the network edge . 1.3. OpenShift Container Platform host architecture: control plane and compute nodes The OpenShift Container Platform architecture allows you to select a standard Kubernetes role for each of the discovered hosts. These roles define the function of the host within the cluster. The roles can be one of the standard Kubernetes types: control plane (master) or compute (worker) . 1.3.1. About assigning roles to hosts During the installation process, you can select a role for a host or configure the Assisted Installer to assign it for you. The options are as follows: Control plane (master) node - The control plane nodes run the services that are required to control the cluster, including the API server. The control plane schedules workloads, maintains cluster state, and ensures stability. Control plane nodes are also known as master nodes. Compute (worker) node - The compute nodes are responsible for executing workloads for cluster users. Compute nodes advertise their capacity, so that the control plane scheduler can identify suitable compute nodes for running pods and containers. Compute nodes are also known as worker nodes. Auto-assign - This option allows the Assisted Installer to automatically select a role for each of the hosts, based on detected hardware and network latency. You can change the role at any time before installation starts. To assign a role to a host, see either of the following sections: Configuring hosts (Web console), step 4 Assigning roles to hosts (Web console and API) 1.3.2. About specifying the number of control plane nodes for your cluster Using a higher number of control plane (master) nodes boosts fault tolerance and availability, minimizing downtime during failures. All versions of OpenShift Container Platform support one or three control plane nodes, where one control plane node is a Single-node OpenShift cluster. From OpenShift Container Platform version 4.18 and higher, the Assisted Installer also supports four or five control plane nodes on a bare metal or user-managed networking platform with an x86_64 architecture. An implementation can support any number of compute nodes. To define the required number of control plane nodes, see either of the following sections: Setting the cluster details (web console), step 12 Registering a new cluster (API), step 2 1.3.3. About scheduling workloads on control plane nodes Scheduling workloads to run on control plane nodes improves efficiency and maximizes resource utilization. You can enable this option during installation setup or as a postinstallation step. Use the following guidelines to determine when to use this feature: single-node OpenShift or small clusters (up to four nodes): The system schedules workloads on control plane nodes by default. This setting cannot be changed. Medium clusters (five to ten nodes): Scheduling workloads to run on control plane nodes in addition to worker nodes is the recommended configuration. Large clusters (more than ten nodes): Configuring control plane nodes as schedulable is not recommended. For instructions on configuring control plane nodes as schedulable during the installation setup, see the following sections: Adding hosts to the cluster (web console), step 2 . Scheduling workloads to run on control plane nodes (API) . For instructions on configuring schedulable control plane nodes following an installation, see Configuring control plane nodes as schedulable in the OpenShift Container Platform documentation. Important When you configure control plane nodes to be schedulable for workloads, an additional subscription is required for each control plane node that function as a compute (worker) node. 1.3.4. Role-related configuration validations The Assisted Installer monitors the number of hosts as one of the conditions for proceding through the cluster installation stages. The logic for determining when a cluster has a sufficient number of installed hosts to proceed is as follows: The number of control plane (master) nodes to install must match the number of control plane nodes that the user requests. For compute (worker) nodes, the requirement depends on the number of compute nodes that the user requests: If the user requests fewer than two compute nodes, the Assisted Installer accepts any number of installed compute nodes, because the control plane nodes remain schedulable for workloads. If the user requests two or more compute nodes, the Assisted Installer installs at least two compute nodes, ensuring that the control plane nodes are not schedulable for workloads. For details, see "About scheduling workloads on control plane nodes" in this section. This logic ensures that the cluster reaches a stable and expected state before continuing with the installation process. 1.3.5. Additional resources For detailed information on control plane and compute nodes, see OpenShift Container Platform architecture . 1.4. API support policy Assisted Installer APIs are supported for a minimum of three months from the announcement of deprecation.