Installing a cluster on vSphere

In OKD version 4.14, you can install a cluster on your VMware vSphere instance by using installer-provisioned infrastructure.

Prerequisites

• You reviewed details about the OKD installation and update processes.

• You read the documentation on selecting a cluster installation method and preparing it for users.

• You provisioned persistent storage for your cluster. To deploy a private image registry, your storage must provide ReadWriteMany access modes.

• The OKD installer requires access to port 443 on the vCenter and ESXi hosts. You verified that port 443 is accessible.

• If you use a firewall, you confirmed with the administrator that port 443 is accessible. Control plane nodes must be able to reach vCenter and ESXi hosts on port 443 for the installation to succeed.

• If you use a firewall, you configured it to allow the sites that your cluster requires access to.

  Be sure to also review this site list if you are configuring a proxy.

VMware vSphere infrastructure requirements

You must install the OKD cluster on a VMware vSphere version 7.0 Update 2 or later instance that meets the requirements for the components that you use.

You can host the VMware vSphere infrastructure on-premise or on a VMware Cloud Verified provider that meets the requirements outlined in the following tables:

Network connectivity requirements

You must configure the network connectivity between machines to allow OKD cluster components to communicate.

Review the following details about the required network ports.

VMware vSphere CSI Driver Operator requirements

To install the vSphere CSI Driver Operator, the following requirements must be met:

• VMware vSphere version 7.0 Update 2 or later

• vCenter 7.0 Update 2 or later

• Virtual machines of hardware version 15 or later

• No third-party vSphere CSI driver already installed in the cluster

If a third-party vSphere CSI driver is present in the cluster, OKD does not overwrite it. The presence of a third-party vSphere CSI driver prevents OKD from updating to OKD 4.13 or later.

Additional resources

• To remove a third-party vSphere CSI driver, see Removing a third-party vSphere CSI Driver.

• To update the hardware version for your vSphere nodes, see Updating hardware on nodes running in vSphere.

vCenter requirements

Before you install an OKD cluster on your vCenter that uses infrastructure that the installer provisions, you must prepare your environment.

Required vCenter account privileges

To install an OKD cluster in a vCenter, the installation program requires access to an account with privileges to read and create the required resources. Using an account that has global administrative privileges is the simplest way to access all of the necessary permissions.

If you cannot use an account with global administrative privileges, you must create roles to grant the privileges necessary for OKD cluster installation. While most of the privileges are always required, some are required only if you plan for the installation program to provision a folder to contain the OKD cluster on your vCenter instance, which is the default behavior. You must create or amend vSphere roles for the specified objects to grant the required privileges.

An additional role is required if the installation program is to create a vSphere virtual machine folder.

Roles and privileges required for installation in vSphere API

Roles and privileges required for installation in vCenter graphical user interface (GUI)

Additionally, the user requires some ReadOnly permissions, and some of the roles require permission to propogate the permissions to child objects. These settings vary depending on whether or not you install the cluster into an existing folder.

Required permissions and propagation settings

For more information about creating an account with only the required privileges, see vSphere Permissions and User Management Tasks in the vSphere documentation.

Using OKD with vMotion

If you intend on using vMotion in your vSphere environment, consider the following before installing an OKD cluster.

• OKD generally supports compute-only vMotion. Using Storage vMotion can cause issues and is not supported.

  To help ensure the uptime of your compute and control plane nodes, it is recommended that you follow the VMware best practices for vMotion. It is also recommended to use VMware anti-affinity rules to improve the availability of OKD during maintenance or hardware issues.

  For more information about vMotion and anti-affinity rules, see the VMware vSphere documentation for vMotion networking requirements and VM anti-affinity rules.

• If you are using vSphere volumes in your pods, migrating a VM across datastores either manually or through Storage vMotion causes, invalid references within OKD persistent volume (PV) objects. These references prevent affected pods from starting up and can result in data loss.

• Similarly, OKD does not support selective migration of VMDKs across datastores, using datastore clusters for VM provisioning or for dynamic or static provisioning of PVs, or using a datastore that is part of a datastore cluster for dynamic or static provisioning of PVs.

  You can specify the path of any datastore that exists in a datastore cluster. By default, Storage Distributed Resource Scheduler (SDRS), which uses Storage vMotion, is automatically enabled for a datastore cluster. Red Hat does not support Storage vMotion, so you must disable Storage DRS to avoid data loss issues for your OKD cluster. If you must specify VMs across multiple datastores, use a datastore object to specify a failure domain in your cluster’s install-config.yaml configuration file. For more information, see “VMware vSphere region and zone enablement”.

Cluster resources

When you deploy an OKD cluster that uses installer-provisioned infrastructure, the installation program must be able to create several resources in your vCenter instance.

A standard OKD installation creates the following vCenter resources:

• 1 Folder

• 1 Tag category

• 1 Tag

• Virtual machines:

  • 1 template

  • 1 temporary bootstrap node

  • 3 control plane nodes

  • 3 compute machines

Although these resources use 856 GB of storage, the bootstrap node is destroyed during the cluster installation process. A minimum of 800 GB of storage is required to use a standard cluster.

If you deploy more compute machines, the OKD cluster will use more storage.

Cluster limits

Available resources vary between clusters. The number of possible clusters within a vCenter is limited primarily by available storage space and any limitations on the number of required resources. Be sure to consider both limitations to the vCenter resources that the cluster creates and the resources that you require to deploy a cluster, such as IP addresses and networks.

Networking requirements

Use Dynamic Host Configuration Protocol (DHCP) for the network and ensure that the DHCP server is configured to provide persistent IP addresses to the cluster machines.

Configure the default gateway to use the DHCP server. All nodes must be in the same VLAN. You cannot scale the cluster using a second VLAN as a Day 2 operation.

You must use the Dynamic Host Configuration Protocol (DHCP) for the network and ensure that the DHCP server is configured to provide persistent IP addresses to the cluster machines. In the DHCP lease, you must configure the DHCP to use the default gateway. All nodes must be in the same VLAN. You cannot scale the cluster using a second VLAN as a Day 2 operation.

Additionally, you must create the following networking resources before you install the OKD cluster:

Required IP Addresses

For a network that uses DHCP, an installer-provisioned vSphere installation requires two static IP addresses:

• The API address is used to access the cluster API.

• The Ingress address is used for cluster ingress traffic.

You must provide these IP addresses to the installation program when you install the OKD cluster.

DNS records

You must create DNS records for two static IP addresses in the appropriate DNS server for the vCenter instance that hosts your OKD cluster. In each record, <cluster_name> is the cluster name and <base_domain> is the cluster base domain that you specify when you install the cluster. A complete DNS record takes the form: <component>.<cluster_name>.<base_domain>..

Static IP addresses for vSphere nodes

You can provision bootstrap, control plane, and compute nodes to be configured with static IP addresses in environments where Dynamic Host Configuration Protocol (DHCP) does not exist. To configure this environment, you must provide values to the platform.vsphere.hosts.role parameter in the install-config.yaml file.

By default, the installation program is configured to use the DHCP for the network, but this network has limited configurable capabilities.

After you define one or more machine pools in your install-config.yaml file, you can define network definitions for nodes on your network. Ensure that the number of network definitions matches the number of machine pools that you configured for your cluster.

The following example shows a network configuration for a node with the role compute:

---
platform:
  vsphere:
    hosts:
    - role: compute (1)
      networkDevice:
        ipAddrs:
        - 192.168.204.10/24 (2)
        gateway: 192.168.204.1 (3)
        nameservers:
        - 192.168.204.1 (4)
---

After you deployed your cluster to run nodes with static IP addresses, you can scale a machine to use one of these static IP addresses. Additionally, you can use a machine set to configure a machine to use one of the configured static IP addresses.

• Scaling machines to use static IP addresses

• Using a machine set to scale machines with configured static IP addresses

Generating a key pair for cluster node SSH access

During an OKD installation, you can provide an SSH public key to the installation program. The key is passed to the Fedora CoreOS (FCOS) nodes through their Ignition config files and is used to authenticate SSH access to the nodes. The key is added to the ~/.ssh/authorized_keys list for the core user on each node, which enables password-less authentication.

After the key is passed to the nodes, you can use the key pair to SSH in to the FCOS nodes as the user core. To access the nodes through SSH, the private key identity must be managed by SSH for your local user.

If you want to SSH in to your cluster nodes to perform installation debugging or disaster recovery, you must provide the SSH public key during the installation process. The ./openshift-install gather command also requires the SSH public key to be in place on the cluster nodes.

Procedure

1. If you do not have an existing SSH key pair on your local machine to use for authentication onto your cluster nodes, create one. For example, on a computer that uses a Linux operating system, run the following command:

   $ ssh-keygen -t ed25519 -N '' -f <path>/<file_name> (1)

   1	Specify the path and file name, such as ~/.ssh/id_ed25519, of the new SSH key. If you have an existing key pair, ensure your public key is in the your ~/.ssh directory.

   If you plan to install an OKD cluster that uses the Fedora cryptographic libraries that have been submitted to NIST for FIPS 140-2/140-3 Validation on only the x86_64, ppc64le, and s390x architectures, do not create a key that uses the ed25519 algorithm. Instead, create a key that uses the rsa or ecdsa algorithm.

2. View the public SSH key:

   $ cat <path>/<file_name>.pub

   For example, run the following to view the ~/.ssh/id_ed25519.pub public key:

   $ cat ~/.ssh/id_ed25519.pub

3. Add the SSH private key identity to the SSH agent for your local user, if it has not already been added. SSH agent management of the key is required for password-less SSH authentication onto your cluster nodes, or if you want to use the ./openshift-install gather command.

   On some distributions, default SSH private key identities such as ~/.ssh/id_rsa and ~/.ssh/id_dsa are managed automatically.

   1. If the ssh-agent process is not already running for your local user, start it as a background task:

      $ eval "$(ssh-agent -s)"

      Example output

      Agent pid 31874

      If your cluster is in FIPS mode, only use FIPS-compliant algorithms to generate the SSH key. The key must be either RSA or ECDSA.

4. Add your SSH private key to the ssh-agent:

   $ ssh-add <path>/<file_name> (1)

   1	Specify the path and file name for your SSH private key, such as ~/.ssh/id_ed25519

   Example output

   Identity added: /home/<you>/<path>/<file_name> (<computer_name>)

Next steps

• When you install OKD, provide the SSH public key to the installation program.

Obtaining the installation program

Before you install OKD, download the installation file on the host you are using for installation.

Prerequisites

• You have a machine that runs Linux, for example Red Hat Enterprise Linux 8, with 500 MB of local disk space.

  If you attempt to run the installation program on macOS, a known issue related to the golang compiler causes the installation of the OKD cluster to fail. For more information about this issue, see the section named “Known Issues” in the OKD 4.14 release notes document.

Procedure

1. Download installer from https://github.com/openshift/okd/releases

   The installation program creates several files on the computer that you use to install your cluster. You must keep the installation program and the files that the installation program creates after you finish installing the cluster. Both files are required to delete the cluster.

   Deleting the files created by the installation program does not remove your cluster, even if the cluster failed during installation. To remove your cluster, complete the OKD uninstallation procedures for your specific cloud provider.

2. Extract the installation program. For example, on a computer that uses a Linux operating system, run the following command:

   $ tar -xvf openshift-install-linux.tar.gz

3. Download your installation pull secret from the Red Hat OpenShift Cluster Manager. This pull secret allows you to authenticate with the services that are provided by the included authorities, including Quay.io, which serves the container images for OKD components.

   Using a pull secret from the Red Hat OpenShift Cluster Manager is not required. You can use a pull secret for another private registry. Or, if you do not need the cluster to pull images from a private registry, you can use {"auths":{"fake":{"auth":"aWQ6cGFzcwo="}}} as the pull secret when prompted during the installation.

   If you do not use the pull secret from the Red Hat OpenShift Cluster Manager:

   • Red Hat Operators are not available.

   • The Telemetry and Insights operators do not send data to Red Hat.

   • Content from the Red Hat Container Catalog registry, such as image streams and Operators, are not available.

Adding vCenter root CA certificates to your system trust

Because the installation program requires access to your vCenter’s API, you must add your vCenter’s trusted root CA certificates to your system trust before you install an OKD cluster.

Procedure

1. From the vCenter home page, download the vCenter’s root CA certificates. Click Download trusted root CA certificates in the vSphere Web Services SDK section. The <vCenter>/certs/download.zip file downloads.

2. Extract the compressed file that contains the vCenter root CA certificates. The contents of the compressed file resemble the following file structure:

   certs
   ├── lin
   │   ├── 108f4d17.0
   │   ├── 108f4d17.r1
   │   ├── 7e757f6a.0
   │   ├── 8e4f8471.0
   │   └── 8e4f8471.r0
   ├── mac
   │   ├── 108f4d17.0
   │   ├── 108f4d17.r1
   │   ├── 7e757f6a.0
   │   ├── 8e4f8471.0
   │   └── 8e4f8471.r0
   └── win
       ├── 108f4d17.0.crt
       ├── 108f4d17.r1.crl
       ├── 7e757f6a.0.crt
       ├── 8e4f8471.0.crt
       └── 8e4f8471.r0.crl
   3 directories, 15 files

3. Add the files for your operating system to the system trust. For example, on a Fedora operating system, run the following command:

   # cp certs/lin/* /etc/pki/ca-trust/source/anchors

4. Update your system trust. For example, on a Fedora operating system, run the following command:

   # update-ca-trust extract

Deploying the cluster

You can install OKD on a compatible cloud platform.

Prerequisites

• You have the OKD installation program and the pull secret for your cluster.

• You have verified that the cloud provider account on your host has the correct permissions to deploy the cluster. An account with incorrect permissions causes the installation process to fail with an error message that displays the missing permissions.

• Optional: Before you create the cluster, configure an external load balancer in place of the default load balancer.

  You do not need to specify API and Ingress static addresses for your installation program. If you choose this configuration, you must take additional actions to define network targets that accept an IP address from each referenced vSphere subnet. See the section “Configuring an external load balancer”.

Procedure

1. Change to the directory that contains the installation program and initialize the cluster deployment:

   $ ./openshift-install create cluster --dir <installation_directory> \ (1)
       --log-level=info (2)

   1	For <installation_directory>, specify the directory name to store the files that the installation program creates.
   2	To view different installation details, specify warn, debug, or error instead of info.

   When specifying the directory:

   • Verify that the directory has the execute permission. This permission is required to run Terraform binaries under the installation directory.

   • Use an empty directory. Some installation assets, such as bootstrap X.509 certificates, have short expiration intervals, therefore you must not reuse an installation directory. If you want to reuse individual files from another cluster installation, you can copy them into your directory. However, the file names for the installation assets might change between releases. Use caution when copying installation files from an earlier OKD version.

2. Provide values at the prompts:

   1. Optional: Select an SSH key to use to access your cluster machines.

      For production OKD clusters on which you want to perform installation debugging or disaster recovery, specify an SSH key that your ssh-agent process uses.

   2. Select vsphere as the platform to target.

   3. Specify the name of your vCenter instance.

   4. Specify the user name and password for the vCenter account that has the required permissions to create the cluster.

      The installation program connects to your vCenter instance.

      Some VMware vCenter Single Sign-On (SSO) environments with Active Directory (AD) integration might primarily require you to use the traditional login method, which requires the <domain>\ construct. To ensure that vCenter account permission checks complete properly, consider using the User Principal Name (UPN) login method, such as <username>@<fully_qualified_domainname>.

   5. Select the data center in your vCenter instance to connect to.

   6. Select the default vCenter datastore to use.

      Datastore and cluster names cannot exceed 60 characters; therefore, ensure the combined string length does not exceed the 60 character limit.

   7. Select the vCenter cluster to install the OKD cluster in. The installation program uses the root resource pool of the vSphere cluster as the default resource pool.

   8. Select the network in the vCenter instance that contains the virtual IP addresses and DNS records that you configured.

   9. Enter the virtual IP address that you configured for control plane API access.

   10. Enter the virtual IP address that you configured for cluster ingress.

   11. Enter the base domain. This base domain must be the same one that you used in the DNS records that you configured.

   12. Enter a descriptive name for your cluster. The cluster name must be the same one that you used in the DNS records that you configured.

       Datastore and cluster names cannot exceed 60 characters; therefore, ensure the combined string length does not exceed the 60 character limit.

   13. Paste the pull secret from the Red Hat OpenShift Cluster Manager.

       • If you do not have a pull secret from the Red Hat OpenShift Cluster Manager, you can paste the pull secret another private registry.

       • If you do not need the cluster to pull images from a private registry, you can paste {"auths":{"fake":{"auth":"aWQ6cGFzcwo="}}} as the pull secret.

Verification

When the cluster deployment completes successfully:

• The terminal displays directions for accessing your cluster, including a link to the web console and credentials for the kubeadmin user.

• Credential information also outputs to <installation_directory>/.openshift_install.log.

Example output

...
INFO Install complete!
INFO To access the cluster as the system:admin user when using 'oc', run 'export KUBECONFIG=/home/myuser/install_dir/auth/kubeconfig'
INFO Access the OpenShift web-console here: https://console-openshift-console.apps.mycluster.example.com
INFO Login to the console with user: "kubeadmin", and password: "password"
INFO Time elapsed: 36m22s

Installing the OpenShift CLI by downloading the binary

You can install the OpenShift CLI (oc) to interact with OKD from a command-line interface. You can install oc on Linux, Windows, or macOS.

Installing the OpenShift CLI on Linux

You can install the OpenShift CLI (oc) binary on Linux by using the following procedure.

Procedure

1. Navigate to https://mirror.openshift.com/pub/openshift-v4/clients/oc/latest/ and choose the folder for your operating system and architecture.

2. Download oc.tar.gz.

3. Unpack the archive:

   $ tar xvf <file>

4. Place the oc binary in a directory that is on your PATH.

   To check your PATH, execute the following command:

   $ echo $PATH

After you install the OpenShift CLI, it is available using the oc command:

$ oc <command>

Installing the OpenShift CLI on Windows

You can install the OpenShift CLI (oc) binary on Windows by using the following procedure.

Procedure

1. Navigate to https://mirror.openshift.com/pub/openshift-v4/clients/oc/latest/ and choose the folder for your operating system and architecture.

2. Download oc.zip.

3. Unzip the archive with a ZIP program.

4. Move the oc binary to a directory that is on your PATH.

   To check your PATH, open the command prompt and execute the following command:

   C:\> path

After you install the OpenShift CLI, it is available using the oc command:

C:\> oc <command>

Installing the OpenShift CLI on macOS

You can install the OpenShift CLI (oc) binary on macOS by using the following procedure.

Procedure

1. Navigate to https://mirror.openshift.com/pub/openshift-v4/clients/oc/latest/ and choose the folder for your operating system and architecture.

2. Download oc.tar.gz.

3. Unpack and unzip the archive.

4. Move the oc binary to a directory on your PATH.

   To check your PATH, open a terminal and execute the following command:

   $ echo $PATH

After you install the OpenShift CLI, it is available using the oc command:

$ oc <command>

Logging in to the cluster by using the CLI

You can log in to your cluster as a default system user by exporting the cluster kubeconfig file. The kubeconfig file contains information about the cluster that is used by the CLI to connect a client to the correct cluster and API server. The file is specific to a cluster and is created during OKD installation.

Prerequisites

• You deployed an OKD cluster.

• You installed the oc CLI.

Procedure

1. Export the kubeadmin credentials:

   $ export KUBECONFIG=<installation_directory>/auth/kubeconfig (1)

   1	For <installation_directory>, specify the path to the directory that you stored the installation files in.

2. Verify you can run oc commands successfully using the exported configuration:

   $ oc whoami

   Example output

   system:admin

Creating registry storage

After you install the cluster, you must create storage for the registry Operator.

Image registry removed during installation

On platforms that do not provide shareable object storage, the OpenShift Image Registry Operator bootstraps itself as Removed. This allows openshift-installer to complete installations on these platform types.

After installation, you must edit the Image Registry Operator configuration to switch the managementState from Removed to Managed.

Image registry storage configuration

The Image Registry Operator is not initially available for platforms that do not provide default storage. After installation, you must configure your registry to use storage so that the Registry Operator is made available.

Instructions are shown for configuring a persistent volume, which is required for production clusters. Where applicable, instructions are shown for configuring an empty directory as the storage location, which is available for only non-production clusters.

Additional instructions are provided for allowing the image registry to use block storage types by using the Recreate rollout strategy during upgrades.

Configuring registry storage for VMware vSphere

As a cluster administrator, following installation you must configure your registry to use storage.

Prerequisites

• Cluster administrator permissions.

• A cluster on VMware vSphere.

• Persistent storage provisioned for your cluster, such as Red Hat OpenShift Data Foundation.

  OKD supports ReadWriteOnce access for image registry storage when you have only one replica. ReadWriteOnce access also requires that the registry uses the Recreate rollout strategy. To deploy an image registry that supports high availability with two or more replicas, ReadWriteMany access is required.

• Must have “100Gi” capacity.

Procedure

1. To configure your registry to use storage, change the spec.storage.pvc in the configs.imageregistry/cluster resource.

   When you use shared storage, review your security settings to prevent outside access.

2. Verify that you do not have a registry pod:

   $ oc get pod -n openshift-image-registry -l docker-registry=default

   Example output

   No resourses found in openshift-image-registry namespace

   If you do have a registry pod in your output, you do not need to continue with this procedure.

3. Check the registry configuration:

   $ oc edit configs.imageregistry.operator.openshift.io

   Example output

   storage:
     pvc:
       claim: (1)

   1

   Leave the claim field blank to allow the automatic creation of an image-registry-storage persistent volume claim (PVC). The PVC is generated based on the default storage class. However, be aware that the default storage class might provide ReadWriteOnce (RWO) volumes, such as a RADOS Block Device (RBD), which can cause issues when you replicate to more than one replica.

4. Check the clusteroperator status:

   $ oc get clusteroperator image-registry

   Example output

   NAME             VERSION                              AVAILABLE   PROGRESSING   DEGRADED   SINCE   MESSAGE
   image-registry   4.7                                  True        False         False      6h50m

Configuring block registry storage for VMware vSphere

To allow the image registry to use block storage types such as vSphere Virtual Machine Disk (VMDK) during upgrades as a cluster administrator, you can use the Recreate rollout strategy.

Procedure

1. To set the image registry storage as a block storage type, patch the registry so that it uses the Recreate rollout strategy and runs with only 1 replica:

   $ oc patch config.imageregistry.operator.openshift.io/cluster --type=merge -p '{"spec":{"rolloutStrategy":"Recreate","replicas":1}}'

2. Provision the PV for the block storage device, and create a PVC for that volume. The requested block volume uses the ReadWriteOnce (RWO) access mode.

   1. Create a pvc.yaml file with the following contents to define a VMware vSphere PersistentVolumeClaim object:

      kind: PersistentVolumeClaim
      apiVersion: v1
      metadata:
        name: image-registry-storage (1)
        namespace: openshift-image-registry (2)
      spec:
        accessModes:
        - ReadWriteOnce (3)
        resources:
          requests:
            storage: 100Gi (4)

      1	A unique name that represents the PersistentVolumeClaim object.
      2	The namespace for the PersistentVolumeClaim object, which is openshift-image-registry.
      3	The access mode of the persistent volume claim. With ReadWriteOnce, the volume can be mounted with read and write permissions by a single node.
      4	The size of the persistent volume claim.

   2. Create the PersistentVolumeClaim object from the file:

      $ oc create -f pvc.yaml -n openshift-image-registry

3. Edit the registry configuration so that it references the correct PVC:

   $ oc edit config.imageregistry.operator.openshift.io -o yaml

   Example output

   storage:
     pvc:
       claim: (1)

   1	By creating a custom PVC, you can leave the claim field blank for the default automatic creation of an image-registry-storage PVC.

For instructions about configuring registry storage so that it references the correct PVC, see Configuring the registry for vSphere.

Backing up VMware vSphere volumes

OKD provisions new volumes as independent persistent disks to freely attach and detach the volume on any node in the cluster. As a consequence, it is not possible to back up volumes that use snapshots, or to restore volumes from snapshots. See Snapshot Limitations for more information.

Procedure

To create a backup of persistent volumes:

1. Stop the application that is using the persistent volume.

2. Clone the persistent volume.

3. Restart the application.

4. Create a backup of the cloned volume.

5. Delete the cloned volume.

Additional resources

• See About remote health monitoring for more information about the Telemetry service

Configuring an external load balancer

You can configure an OKD cluster to use an external load balancer in place of the default load balancer.

Red Hat supports the following services for an external load balancer:

• OpenShift API

• Ingress Controller

You can choose to configure one or both of these services for an external load balancer. Configuring only the Ingress Controller service is a common configuration option.

The following configuration options are supported for external load balancers:

• Use a node selector to map the Ingress Controller to a specific set of nodes. You must assign a static IP address to each node in this set, or configure each node to receive the same IP address from the Dynamic Host Configuration Protocol (DHCP). Infrastructure nodes commonly receive this type of configuration.

• Target all IP addresses on a subnet. This configuration can reduce maintenance overhead, because you can create and destroy nodes within those networks without reconfiguring the load balancer targets. If you deploy your ingress pods by using a machine set on a smaller network, such as a /27 or /28, you can simplify your load balancer targets.

  You can list all IP addresses that exist in a network by checking the machine config pool’s resources.

Considerations

• For a front-end IP address, you can use the same IP address for the front-end IP address, the Ingress Controller’s load balancer, and API load balancer. Check the vendor’s documentation for this capability.

• For a back-end IP address, ensure that an IP address for an OKD control plane node does not change during the lifetime of the external load balancer. You can achieve this by completing one of the following actions:

  • Assign a static IP address to each control plane node.

  • Configure each node to receive the same IP address from the DHCP every time the node requests a DHCP lease. Depending on the vendor, the DHCP lease might be in the form of an IP reservation or a static DHCP assignment.

• Manually define each node that runs the Ingress Controller in the external load balancer for the Ingress Controller back-end service. For example, if the Ingress Controller moves to an undefined node, a connection outage can occur.

OpenShift API prerequisites

• You defined a front-end IP address.

• TCP ports 6443 and 22623 are exposed on the front-end IP address of your load balancer. Check the following items:

  • Port 6443 provides access to the OpenShift API service.

  • Port 22623 can provide ignition startup configurations to nodes.

• The front-end IP address and port 6443 are reachable by all users of your system with a location external to your OKD cluster.

• The front-end IP address and port 22623 are reachable only by OKD nodes.

• The load balancer backend can communicate with OKD control plane nodes on port 6443 and 22623.

Ingress Controller prerequisites

• You defined a front-end IP address.

• TCP ports 443 and 80 are exposed on the front-end IP address of your load balancer.

• The front-end IP address, port 80 and port 443 are be reachable by all users of your system with a location external to your OKD cluster.

• The front-end IP address, port 80 and port 443 are reachable to all nodes that operate in your OKD cluster.

• The load balancer backend can communicate with OKD nodes that run the Ingress Controller on ports 80, 443, and 1936.

Prerequisite for health check URL specifications

You can configure most load balancers by setting health check URLs that determine if a service is available or unavailable. OKD provides these health checks for the OpenShift API, Machine Configuration API, and Ingress Controller backend services.

The following examples demonstrate health check specifications for the previously listed backend services:

Example of a Kubernetes API health check specification

Path: HTTPS:6443/readyz
Healthy threshold: 2
Unhealthy threshold: 2
Timeout: 10
Interval: 10

Example of a Machine Config API health check specification

Path: HTTPS:22623/healthz
Healthy threshold: 2
Unhealthy threshold: 2
Timeout: 10
Interval: 10

Example of an Ingress Controller health check specification

Path: HTTP:1936/healthz/ready
Healthy threshold: 2
Unhealthy threshold: 2
Timeout: 5
Interval: 10

Procedure

1. Configure the HAProxy Ingress Controller, so that you can enable access to the cluster from your load balancer on ports 6443, 443, and 80:

   Example HAProxy configuration

   #...
   listen my-cluster-api-6443
       bind 192.168.1.100:6443
       mode tcp
       balance roundrobin
     option httpchk
     http-check connect
     http-check send meth GET uri /readyz
     http-check expect status 200
       server my-cluster-master-2 192.168.1.101:6443 check inter 10s rise 2 fall 2
       server my-cluster-master-0 192.168.1.102:6443 check inter 10s rise 2 fall 2
       server my-cluster-master-1 192.168.1.103:6443 check inter 10s rise 2 fall 2
   listen my-cluster-machine-config-api-22623
       bind 192.168.1.1000.0.0.0:22623
       mode tcp
       balance roundrobin
     option httpchk
     http-check connect
     http-check send meth GET uri /healthz
     http-check expect status 200
       server my-cluster-master-2 192.0168.21.2101:22623 check inter 10s rise 2 fall 2
       server my-cluster-master-0 192.168.1.1020.2.3:22623 check inter 10s rise 2 fall 2
       server my-cluster-master-1 192.168.1.1030.2.1:22623 check inter 10s rise 2 fall 2
   listen my-cluster-apps-443
           bind 192.168.1.100:443
           mode tcp
           balance roundrobin
       option httpchk
       http-check connect
       http-check send meth GET uri /healthz/ready
       http-check expect status 200
           server my-cluster-worker-0 192.168.1.111:443 check port 1936 inter 10s rise 2 fall 2
           server my-cluster-worker-1 192.168.1.112:443 check port 1936 inter 10s rise 2 fall 2
           server my-cluster-worker-2 192.168.1.113:443 check port 1936 inter 10s rise 2 fall 2
   listen my-cluster-apps-80
           bind 192.168.1.100:80
           mode tcp
           balance roundrobin
       option httpchk
       http-check connect
       http-check send meth GET uri /healthz/ready
       http-check expect status 200
           server my-cluster-worker-0 192.168.1.111:80 check port 1936 inter 10s rise 2 fall 2
           server my-cluster-worker-1 192.168.1.112:80 check port 1936 inter 10s rise 2 fall 2
           server my-cluster-worker-2 192.168.1.113:80 check port 1936 inter 10s rise 2 fall 2
   # ...

2. Use the curl CLI command to verify that the external load balancer and its resources are operational:

   1. Verify that the cluster machine configuration API is accessible to the Kubernetes API server resource, by running the following command and observing the response:

      $ curl https://<loadbalancer_ip_address>:6443/version --insecure

      If the configuration is correct, you receive a JSON object in response:

      {
        "major": "1",
        "minor": "11+",
        "gitVersion": "v1.11.0+ad103ed",
        "gitCommit": "ad103ed",
        "gitTreeState": "clean",
        "buildDate": "2019-01-09T06:44:10Z",
        "goVersion": "go1.10.3",
        "compiler": "gc",
        "platform": "linux/amd64"
      }

   2. Verify that the cluster machine configuration API is accessible to the Machine config server resource, by running the following command and observing the output:

      $ curl -v https://<loadbalancer_ip_address>:22623/healthz --insecure

      If the configuration is correct, the output from the command shows the following response:

      HTTP/1.1 200 OK
      Content-Length: 0

   3. Verify that the controller is accessible to the Ingress Controller resource on port 80, by running the following command and observing the output:

      $ curl -I -L -H "Host: console-openshift-console.apps.<cluster_name>.<base_domain>" http://<load_balancer_front_end_IP_address>

      If the configuration is correct, the output from the command shows the following response:

      HTTP/1.1 302 Found
      content-length: 0
      location: https://console-openshift-console.apps.ocp4.private.opequon.net/
      cache-control: no-cache

   4. Verify that the controller is accessible to the Ingress Controller resource on port 443, by running the following command and observing the output:

      $ curl -I -L --insecure --resolve console-openshift-console.apps.<cluster_name>.<base_domain>:443:<Load Balancer Front End IP Address> https://console-openshift-console.apps.<cluster_name>.<base_domain>

      If the configuration is correct, the output from the command shows the following response:

      HTTP/1.1 200 OK
      referrer-policy: strict-origin-when-cross-origin
      set-cookie: csrf-token=UlYWOyQ62LWjw2h003xtYSKlh1a0Py2hhctw0WmV2YEdhJjFyQwWcGBsja261dGLgaYO0nxzVErhiXt6QepA7g==; Path=/; Secure; SameSite=Lax
      x-content-type-options: nosniff
      x-dns-prefetch-control: off
      x-frame-options: DENY
      x-xss-protection: 1; mode=block
      date: Wed, 04 Oct 2023 16:29:38 GMT
      content-type: text/html; charset=utf-8
      set-cookie: 1e2670d92730b515ce3a1bb65da45062=1bf5e9573c9a2760c964ed1659cc1673; path=/; HttpOnly; Secure; SameSite=None
      cache-control: private

3. Configure the DNS records for your cluster to target the front-end IP addresses of the external load balancer. You must update records to your DNS server for the cluster API and applications over the load balancer.

   Examples of modified DNS records

   <load_balancer_ip_address>  A  api.<cluster_name>.<base_domain>
   A record pointing to Load Balancer Front End

   <load_balancer_ip_address>   A apps.<cluster_name>.<base_domain>
   A record pointing to Load Balancer Front End

   DNS propagation might take some time for each DNS record to become available. Ensure that each DNS record propagates before validating each record.

4. Use the curl CLI command to verify that the external load balancer and DNS record configuration are operational:

   1. Verify that you can access the cluster API, by running the following command and observing the output:

      $ curl https://api.<cluster_name>.<base_domain>:6443/version --insecure

      If the configuration is correct, you receive a JSON object in response:

      {
        "major": "1",
        "minor": "11+",
        "gitVersion": "v1.11.0+ad103ed",
        "gitCommit": "ad103ed",
        "gitTreeState": "clean",
        "buildDate": "2019-01-09T06:44:10Z",
        "goVersion": "go1.10.3",
        "compiler": "gc",
        "platform": "linux/amd64"
        }

   2. Verify that you can access the cluster machine configuration, by running the following command and observing the output:

      $ curl -v https://api.<cluster_name>.<base_domain>:22623/healthz --insecure

      If the configuration is correct, the output from the command shows the following response:

      HTTP/1.1 200 OK
      Content-Length: 0

   3. Verify that you can access each cluster application on port, by running the following command and observing the output:

      $ curl http://console-openshift-console.apps.<cluster_name>.<base_domain> -I -L --insecure

      If the configuration is correct, the output from the command shows the following response:

      HTTP/1.1 302 Found
      content-length: 0
      location: https://console-openshift-console.apps.<cluster-name>.<base domain>/
      cache-control: no-cacheHTTP/1.1 200 OK
      referrer-policy: strict-origin-when-cross-origin
      set-cookie: csrf-token=39HoZgztDnzjJkq/JuLJMeoKNXlfiVv2YgZc09c3TBOBU4NI6kDXaJH1LdicNhN1UsQWzon4Dor9GWGfopaTEQ==; Path=/; Secure
      x-content-type-options: nosniff
      x-dns-prefetch-control: off
      x-frame-options: DENY
      x-xss-protection: 1; mode=block
      date: Tue, 17 Nov 2020 08:42:10 GMT
      content-type: text/html; charset=utf-8
      set-cookie: 1e2670d92730b515ce3a1bb65da45062=9b714eb87e93cf34853e87a92d6894be; path=/; HttpOnly; Secure; SameSite=None
      cache-control: private

   4. Verify that you can access each cluster application on port 443, by running the following command and observing the output:

      $ curl https://console-openshift-console.apps.<cluster_name>.<base_domain> -I -L --insecure

      If the configuration is correct, the output from the command shows the following response:

      HTTP/1.1 200 OK
      referrer-policy: strict-origin-when-cross-origin
      set-cookie: csrf-token=UlYWOyQ62LWjw2h003xtYSKlh1a0Py2hhctw0WmV2YEdhJjFyQwWcGBsja261dGLgaYO0nxzVErhiXt6QepA7g==; Path=/; Secure; SameSite=Lax
      x-content-type-options: nosniff
      x-dns-prefetch-control: off
      x-frame-options: DENY
      x-xss-protection: 1; mode=block
      date: Wed, 04 Oct 2023 16:29:38 GMT
      content-type: text/html; charset=utf-8
      set-cookie: 1e2670d92730b515ce3a1bb65da45062=1bf5e9573c9a2760c964ed1659cc1673; path=/; HttpOnly; Secure; SameSite=None
      cache-control: private

Next steps

• Customize your cluster.

• If necessary, you can opt out of remote health reporting.

• Set up your registry and configure registry storage.

• Optional: View the events from the vSphere Problem Detector Operator to determine if the cluster has permission or storage configuration issues.