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Installer-provisioned installation of OpenShift Container Platform requires:

  1. One provisioner node with Red Hat Enterprise Linux (RHEL) 8.x installed.

  2. Three control plane nodes.

  3. Baseboard Management Controller (BMC) access to each node.

  4. At least one network:

    1. One required routable network

    2. One optional network for provisioning nodes; and,

    3. One optional management network.

Before starting an installer-provisioned installation of OpenShift Container Platform, ensure the hardware environment meets the following requirements.

Node requirements

Installer-provisioned installation involves a number of hardware node requirements:

  • CPU architecture: All nodes must use x86_64 CPU architecture.

  • Similar nodes: Red Hat recommends nodes have an identical configuration per role. That is, Red Hat recommends nodes be the same brand and model with the same CPU, memory, and storage configuration.

  • Baseboard Management Controller: The provisioner node must be able to access the baseboard management controller (BMC) of each OpenShift Container Platform cluster node. You may use IPMI, Redfish, or a proprietary protocol.

  • Latest generation: Nodes must be of the most recent generation. Installer-provisioned installation relies on BMC protocols, which must be compatible across nodes. Additionally, RHEL 8 ships with the most recent drivers for RAID controllers. Ensure that the nodes are recent enough to support RHEL 8 for the provisioner node and RHCOS 8 for the control plane and worker nodes.

  • Registry node: (Optional) If setting up a disconnected mirrored registry, it is recommended the registry reside in its own node.

  • Provisioner node: Installer-provisioned installation requires one provisioner node.

  • Control plane: Installer-provisioned installation requires three control plane nodes for high availability. You can deploy an OpenShift Container Platform cluster with only three control plane nodes, making the control plane nodes schedulable as worker nodes. Smaller clusters are more resource efficient for administrators and developers during development, production, and testing.

  • Worker nodes: While not required, a typical production cluster has two or more worker nodes.

    Do not deploy a cluster with only one worker node, because the cluster will deploy with routers and ingress traffic in a degraded state.

  • Network interfaces: Each node must have at least one 10GB network interface for the routable baremetal network. Each node must have one 10GB network interface for a provisioning network when using the provisioning network for deployment. Using the provisioning network is the default configuration. Network interface names must follow the same naming convention across all nodes. For example, the first NIC name on a node, such as eth0 or eno1, must be the same name on all of the other nodes. The same principle applies to the remaining NICs on each node.

  • Unified Extensible Firmware Interface (UEFI): Installer-provisioned installation requires UEFI boot on all OpenShift Container Platform nodes when using IPv6 addressing on the provisioning network. In addition, UEFI Device PXE Settings must be set to use the IPv6 protocol on the provisioning network NIC, but omitting the provisioning network removes this requirement.

  • Secure Boot: Many production scenarios require nodes with Secure Boot enabled to verify the node only boots with trusted software, such as UEFI firmware drivers, EFI applications, and the operating system. You may deploy with Secure Boot manually or managed.

    1. Manually: To deploy an OpenShift Container Platform cluster with Secure Boot manually, you must enable UEFI boot mode and Secure Boot on each control plane node and each worker node. Red Hat supports Secure Boot with manually enabled UEFI and Secure Boot only when installer-provisioned installations use Redfish virtual media. See "Configuring nodes for Secure Boot manually" in the "Configuring nodes" section for additional details.

    2. Managed: To deploy an OpenShift Container Platform cluster with managed Secure Boot, you must set the bootMode value to UEFISecureBoot in the install-config.yaml file. Red Hat only supports installer-provisioned installation with managed Secure Boot on 10th generation HPE hardware and 13th generation Dell hardware running firmware version 2.75.75.75 or greater. Deploying with managed Secure Boot does not require Redfish virtual media. See "Configuring managed Secure Boot" in the "Setting up the environment for an OpenShift installation" section for details.

      Red Hat does not support Secure Boot with self-generated keys.

Firmware requirements for installing with virtual media

The installer for installer-provisioned OpenShift Container Platform clusters validates the hardware and firmware compatibility with Redfish virtual media. The following table lists supported firmware for installer-provisioned OpenShift Container Platform clusters deployed with Redfish virtual media.

Table 1. Firmware compatibility for Redfish virtual media
Hardware Model Management Firmware Versions

HP

10th Generation

iLO5

N/A

9th Generation

iLO4

N/A

Dell

14th Generation

iDRAC 9

v4.20.20.20 - 04.40.00.00

13th Generation

iDRAC 8

v2.75.75.75+

See the hardware documentation for the nodes or contact the hardware vendor for information on updating the firmware.

There are no known firmware limitations for HP servers.

For Dell servers, ensure the OpenShift Container Platform cluster nodes have AutoAttach Enabled through the iDRAC console. The menu path is: ConfigurationVirtual MediaAttach ModeAutoAttach . With iDRAC 9 firmware version 04.40.00.00, the Virtual Console plug-in defaults to eHTML5, which causes problems with the InsertVirtualMedia workflow. Set the plug-in to HTML5 to avoid this issue. The menu path is: ConfigurationVirtual consolePlug-in TypeHTML5 .

The installer will not initiate installation on a node if the node firmware is below the foregoing versions when installing with virtual media.

Network requirements

Installer-provisioned installation of OpenShift Container Platform involves several network requirements. First, installer-provisioned installation involves an optional non-routable provisioning network for provisioning the operating system on each bare metal node. Second, installer-provisioned installation involves a routable baremetal network.

Configuring NICs

OpenShift Container Platform deploys with two networks:

  • provisioning: The provisioning network is an optional non-routable network used for provisioning the underlying operating system on each node that is a part of the OpenShift Container Platform cluster. The network interface for the provisioning network on each cluster node must have the BIOS or UEFI configured to PXE boot.

    The provisioningNetworkInterface configuration setting specifies the provisioning network NIC name on the control plane nodes, which must be identical on the control plane nodes. The bootMACAddress configuration setting provides a means to specify a particular NIC on each node for the provisioning network.

    The provisioning network is optional, but it is required for PXE booting. If you deploy without a provisioning network, you must use a virtual media BMC addressing option such as redfish-virtualmedia or idrac-virtualmedia.

  • baremetal: The baremetal network is a routable network. You can use any NIC to interface with the baremetal network provided the NIC is not configured to use the provisioning network.

When using a VLAN, each NIC must be on a separate VLAN corresponding to the appropriate network.

Configuring the DNS server

Clients access the OpenShift Container Platform cluster nodes over the baremetal network. A network administrator must configure a subdomain or subzone where the canonical name extension is the cluster name.

<cluster_name>.<domain>

For example:

test-cluster.example.com

OpenShift Container Platform includes functionality that uses cluster membership information to generate A/AAAA records. This resolves the node names to their IP addresses. After the nodes are registered with the API, the cluster can disperse node information without using CoreDNS-mDNS. This eliminates the network traffic associated with multicast DNS.

You must create a DNS entry for the api.<cluster_name>.<domain> domain name on the external DNS because removing CoreDNS causes the local entry to disappear. Failure to create a DNS record for the api.<cluster_name>.<domain> domain name in the external DNS server precludes worker nodes from joining the cluster.

Dynamic Host Configuration Protocol (DHCP) requirements

By default, installer-provisioned installation deploys ironic-dnsmasq with DHCP enabled for the provisioning network. No other DHCP servers should be running on the provisioning network when the provisioningNetwork configuration setting is set to managed, which is the default value. If you have a DHCP server running on the provisioning network, you must set the provisioningNetwork configuration setting to unmanaged in the install-config.yaml file.

Network administrators must reserve IP addresses for each node in the OpenShift Container Platform cluster for the baremetal network on an external DHCP server.

Reserving IP addresses for nodes with the DHCP server

For the baremetal network, a network administrator must reserve a number of IP addresses, including:

  1. Two virtual IP addresses.

    • One IP address for the API endpoint

    • One IP address for the wildcard ingress endpoint

  2. One IP address for the provisioner node.

  3. One IP address for each control plane (master) node.

  4. One IP address for each worker node, if applicable.

Reserving IP addresses so they become static IP addresses

Some administrators prefer to use static IP addresses so that each node’s IP address remains constant in the absence of a DHCP server. To use static IP addresses in the OpenShift Container Platform cluster, reserve the IP addresses with an infinite lease. During deployment, the installer will reconfigure the NICs from DHCP assigned addresses to static IP addresses. NICs with DHCP leases that are not infinite will remain configured to use DHCP.

Networking between external load balancers and control plane nodes

External load balancing services and the control plane nodes must run on the same L2 network, and on the same VLAN when using VLANs to route traffic between the load balancing services and the control plane nodes.

The following table provides an exemplary embodiment of fully qualified domain names. The API and Nameserver addresses begin with canonical name extensions. The hostnames of the control plane and worker nodes are exemplary, so you can use any host naming convention you prefer.

Usage Host Name IP

API

api.<cluster_name>.<domain>

<ip>

Ingress LB (apps)

*.apps.<cluster_name>.<domain>

<ip>

Provisioner node

provisioner.<cluster_name>.<domain>

<ip>

Master-0

openshift-master-0.<cluster_name>.<domain>

<ip>

Master-1

openshift-master-1.<cluster_name>-.<domain>

<ip>

Master-2

openshift-master-2.<cluster_name>.<domain>

<ip>

Worker-0

openshift-worker-0.<cluster_name>.<domain>

<ip>

Worker-1

openshift-worker-1.<cluster_name>.<domain>

<ip>

Worker-n

openshift-worker-n.<cluster_name>.<domain>

<ip>

Network Time Protocol (NTP)

Each OpenShift Container Platform node in the cluster must have access to an NTP server. OpenShift Container Platform nodes use NTP to synchronize their clocks. For example, cluster nodes use SSL certificates that require validation, which might fail if the date and time between the nodes are not in sync.

Define a consistent clock date and time format in each cluster node’s BIOS settings, or installation might fail.

You may reconfigure the control plane nodes to act as NTP servers on disconnected clusters, and reconfigure worker nodes to retrieve time from the control plane nodes.

State-driven network configuration requirements (Technology Preview)

OpenShift Container Platform supports additional post-installation state-driven network configuration on the secondary network interfaces of cluster nodes using kubernetes-nmstate. For example, system administrators might configure a secondary network interface on cluster nodes after installation for a storage network.

Configuration must occur before scheduling pods.

State-driven network configuration requires installing kubernetes-nmstate, and also requires Network Manager running on the cluster nodes. See OpenShift Virtualization > Kubernetes NMState (Tech Preview) for additional details.

Configuring nodes

Configuring nodes when using the provisioning network

Each node in the cluster requires the following configuration for proper installation.

A mismatch between nodes will cause an installation failure.

While the cluster nodes can contain more than two NICs, the installation process only focuses on the first two NICs:

NIC Network VLAN

NIC1

provisioning

<provisioning_vlan>

NIC2

baremetal

<baremetal_vlan>

In the foregoing example, NIC1 is a non-routable network (provisioning) that is only used for the installation of the OpenShift Container Platform cluster.

The Red Hat Enterprise Linux (RHEL) 8.x installation process on the provisioner node might vary. To install Red Hat Enterprise Linux (RHEL) 8.x using a local Satellite server or a PXE server, PXE-enable NIC2.

PXE Boot order

NIC1 PXE-enabled provisioning network

1

NIC2 baremetal network. PXE-enabled is optional.

2

Ensure PXE is disabled on all other NICs.

Configure the control plane and worker nodes as follows:

PXE Boot order

NIC1 PXE-enabled (provisioning network)

1

Configuring nodes without the provisioning network

The installation process requires one NIC:

NIC Network VLAN

NICx

baremetal

<baremetal_vlan>

NICx is a routable network (baremetal) that is used for the installation of the OpenShift Container Platform cluster, and routable to the internet.

The provisioning network is optional, but it is required for PXE booting. If you deploy without a provisioning network, you must use a virtual media BMC addressing option such as redfish-virtualmedia or idrac-virtualmedia.

Configuring nodes for Secure Boot manually

Secure Boot prevents a node from booting unless it verifies the node is using only trusted software, such as UEFI firmware drivers, EFI applications, and the operating system.

Red Hat only supports manually configured Secure Boot when deploying with Redfish virtual media.

To enable Secure Boot manually, refer to the hardware guide for the node and execute the following:

  1. Boot the node and enter the BIOS menu.

  2. Set the node’s boot mode to UEFI Enabled.

  3. Enable Secure Boot.

Red Hat does not support Secure Boot with self-generated keys.

Out-of-band management

Nodes will typically have an additional NIC used by the Baseboard Management Controllers (BMCs). These BMCs must be accessible from the provisioner node.

Each node must be accessible via out-of-band management. When using an out-of-band management network, the provisioner node requires access to the out-of-band management network for a successful OpenShift Container Platform 4 installation.

The out-of-band management setup is out of scope for this document. We recommend setting up a separate management network for out-of-band management. However, using the provisioning network or the baremetal network are valid options.

Required data for installation

Prior to the installation of the OpenShift Container Platform cluster, gather the following information from all cluster nodes:

  • Out-of-band management IP

    • Examples

      • Dell (iDRAC) IP

      • HP (iLO) IP

      • Fujitsu (iRMC) IP

When using the provisioning network
  • NIC1 (provisioning) MAC address

  • NIC2 (baremetal) MAC address

When omitting the provisioning network
  • NICx (baremetal) MAC address

Validation checklist for nodes

When using the provisioning network
  • NIC1 VLAN is configured for the provisioning network. (optional)

  • NIC1 is PXE-enabled on the provisioner, control plane (master), and worker nodes when using a provisioning network. (optional)

  • NIC2 VLAN is configured for the baremetal network.

  • PXE has been disabled on all other NICs.

  • Control plane and worker nodes are configured.

  • All nodes accessible via out-of-band management.

  • A separate management network has been created. (optional)

  • Required data for installation.

When omitting the provisioning network
  • NICx VLAN is configured for the baremetal network.

  • Control plane and worker nodes are configured.

  • All nodes accessible via out-of-band management.

  • A separate management network has been created. (optional)

  • Required data for installation.