In OKD version 4, you can install a cluster on VMware vSphere infrastructure that you provision with customized network configuration options. By customizing your network configuration, your cluster can coexist with existing IP address allocations in your environment and integrate with existing MTU and VXLAN configurations.

You must set most of the network configuration parameters during installation, and you can modify only kubeProxy configuration parameters in a running cluster.

Prerequisites

VMware vSphere infrastructure requirements

You must install the OKD cluster on a VMware vSphere version 6 or 7 instance that meets the requirements for the components that you use.

Table 1. Minimum supported vSphere version for VMware components
Component Minimum supported versions Description

Hypervisor

vSphere 6.5 and later with HW version 13

This version is the minimum version that Fedora CoreOS (FCOS) supports. See the Red Hat Enterprise Linux 8 supported hypervisors list.

Networking (NSX-T)

vSphere 6.5U3 or vSphere 6.7U2 and later

vSphere 6.5U3 or vSphere 6.7U2+ are required for OKD. VMware’s NSX Container Plug-in (NCP) 3.0.2 is certified with OKD 4.6 and NSX-T 3.x+.

Storage with in-tree drivers

vSphere 6.5 and later

This plug-in creates vSphere storage by using the in-tree storage drivers for vSphere included in OKD and can be used when vSphere CSI drivers are not available.

Storage with vSphere CSI driver

vSphere 6.7U3 and later

This plug-in creates vSphere storage by using the standard Container Storage Interface. The vSphere CSI driver is provided and supported by VMware.

If you use a vSphere version 6.5 instance, consider upgrading to 6.7U3 or 7.0 before you install OKD.

You must ensure that the time on your ESXi hosts is synchronized before you install OKD. See Edit Time Configuration for a Host in the VMware documentation.

A limitation of using VPC is that the Storage Distributed Resource Scheduler (SDRS) is not supported. See vSphere Storage for Kubernetes FAQs in the VMware documentation.

Machine requirements for a cluster with user-provisioned infrastructure

For a cluster that contains user-provisioned infrastructure, you must deploy all of the required machines.

Required machines

The smallest OKD clusters require the following hosts:

  • One temporary bootstrap machine

  • Three control plane, or master, machines

  • At least two compute machines, which are also known as worker machines

The cluster requires the bootstrap machine to deploy the OKD cluster on the three control plane machines. You can remove the bootstrap machine after you install the cluster.

To maintain high availability of your cluster, use separate physical hosts for these cluster machines.

The bootstrap, control plane, and compute machines must use the Fedora CoreOS (FCOS) as the operating system.

Network connectivity requirements

All the Fedora CoreOS (FCOS) machines require network in initramfs during boot to fetch Ignition config files from the Machine Config Server. During the initial boot, the machines require either a DHCP server or that static IP addresses be set in order to establish a network connection to download their Ignition config files.

Minimum resource requirements

Each cluster machine must meet the following minimum requirements:

Machine Operating System vCPU Virtual RAM Storage

Bootstrap

FCOS

4

16 GB

120 GB

Control plane

FCOS

4

16 GB

120 GB

Compute

FCOS or RHEL 7.6

2

8 GB

120 GB

Certificate signing requests management

Because your cluster has limited access to automatic machine management when you use infrastructure that you provision, you must provide a mechanism for approving cluster certificate signing requests (CSRs) after installation. The kube-controller-manager only approves the kubelet client CSRs. The machine-approver cannot guarantee the validity of a serving certificate that is requested by using kubelet credentials because it cannot confirm that the correct machine issued the request. You must determine and implement a method of verifying the validity of the kubelet serving certificate requests and approving them.

Creating the user-provisioned infrastructure

Before you deploy an OKD cluster that uses user-provisioned infrastructure, you must create the underlying infrastructure.

Prerequistes
Procedure
  1. Configure DHCP or set static IP addresses on each node.

  2. Provision the required load balancers.

  3. Configure the ports for your machines.

  4. Configure DNS.

  5. Ensure network connectivity.

Networking requirements for user-provisioned infrastructure

All the Fedora CoreOS (FCOS) machines require network in initramfs during boot to fetch Ignition config from the Machine Config Server.

During the initial boot, the machines require either a DHCP server or that static IP addresses be set on each host in the cluster in order to establish a network connection, which allows them to download their Ignition config files.

It is recommended to use the DHCP server to manage the machines for the cluster long-term. Ensure that the DHCP server is configured to provide persistent IP addresses and host names to the cluster machines.

The Kubernetes API server must be able to resolve the node names of the cluster machines. If the API servers and worker nodes are in different zones, you can configure a default DNS search zone to allow the API server to resolve the node names. Another supported approach is to always refer to hosts by their fully-qualified domain names in both the node objects and all DNS requests.

You must configure the network connectivity between machines to allow cluster components to communicate. Each machine must be able to resolve the host names of all other machines in the cluster.

Table 2. All machines to all machines
Protocol Port Description

ICMP

N/A

Network reachability tests

TCP

9000-9999

Host level services, including the node exporter on ports 9100-9101 and the Cluster Version Operator on port 9099.

10250-10259

The default ports that Kubernetes reserves

10256

openshift-sdn

UDP

4789

VXLAN and Geneve

6081

VXLAN and Geneve

9000-9999

Host level services, including the node exporter on ports 9100-9101.

TCP/UDP

30000-32767

Kubernetes NodePort

Table 3. All machines to control plane
Protocol Port Description

TCP

2379-2380

etcd server, peer, and metrics ports

6443

Kubernetes API

Network topology requirements

The infrastructure that you provision for your cluster must meet the following network topology requirements.

OKD requires all nodes to have internet access to pull images for platform containers and provide telemetry data to Red Hat.

Load balancers

Before you install OKD, you must provision two load balancers that meet the following requirements:

  1. API load balancer: Provides a common endpoint for users, both human and machine, to interact with and configure the platform. Configure the following conditions:

    • Layer 4 load balancing only. This can be referred to as Raw TCP, SSL Passthrough, or SSL Bridge mode. If you use SSL Bridge mode, you must enable Server Name Indication (SNI) for the API routes.

    • A stateless load balancing algorithm. The options vary based on the load balancer implementation.

    Session persistence is not required for the API load balancer to function properly.

    Configure the following ports on both the front and back of the load balancers:

    Table 4. API load balancer
    Port Back-end machines (pool members) Internal External Description

    6443

    Bootstrap and control plane. You remove the bootstrap machine from the load balancer after the bootstrap machine initializes the cluster control plane. You must configure the /readyz endpoint for the API server health check probe.

    X

    X

    Kubernetes API server

    22623

    Bootstrap and control plane. You remove the bootstrap machine from the load balancer after the bootstrap machine initializes the cluster control plane.

    X

    Machine Config server

    The load balancer must be configured to take a maximum of 30 seconds from the time the API server turns off the /readyz endpoint to the removal of the API server instance from the pool. Within the time frame after /readyz returns an error or becomes healthy, the endpoint must have been removed or added. Probing every 5 or 10 seconds, with two successful requests to become healthy and three to become unhealthy, are well-tested values.

  2. Application Ingress load balancer: Provides an Ingress point for application traffic flowing in from outside the cluster. Configure the following conditions:

    • Layer 4 load balancing only. This can be referred to as Raw TCP, SSL Passthrough, or SSL Bridge mode. If you use SSL Bridge mode, you must enable Server Name Indication (SNI) for the Ingress routes.

    • A connection-based or session-based persistence is recommended, based on the options available and types of applications that will be hosted on the platform.

    Configure the following ports on both the front and back of the load balancers:

    Table 5. Application Ingress load balancer
    Port Back-end machines (pool members) Internal External Description

    443

    The machines that run the Ingress router pods, compute, or worker, by default.

    X

    X

    HTTPS traffic

    80

    The machines that run the Ingress router pods, compute, or worker by default.

    X

    X

    HTTP traffic

If the true IP address of the client can be seen by the load balancer, enabling source IP-based session persistence can improve performance for applications that use end-to-end TLS encryption.

A working configuration for the Ingress router is required for an OKD cluster. You must configure the Ingress router after the control plane initializes.

Ethernet adaptor hardware address requirements

When provisioning VMs for the cluster, the ethernet interfaces configured for each VM must use a MAC address from the VMware Organizationally Unique Identifier (OUI) allocation ranges:

  • 00:05:69:00:00:00 to 00:05:69:FF:FF:FF

  • 00:0c:29:00:00:00 to 00:0c:29:FF:FF:FF

  • 00:1c:14:00:00:00 to 00:1c:14:FF:FF:FF

  • 00:50:56:00:00:00 to 00:50:56:FF:FF:FF

If a MAC address outside the VMware OUI is used, the cluster installation will not succeed.

User-provisioned DNS requirements

The following DNS records are required for an OKD cluster that uses user-provisioned infrastructure. In each record, <cluster_name> is the cluster name and <base_domain> is the cluster base domain that you specify in the install-config.yaml file. A complete DNS record takes the form: <component>.<cluster_name>.<base_domain>..

Table 6. Required DNS records
Component Record Description

Kubernetes API

api.<cluster_name>.<base_domain>.

This DNS A/AAAA or CNAME record must point to the load balancer for the control plane machines. This record must be resolvable by both clients external to the cluster and from all the nodes within the cluster.

api-int.<cluster_name>.<base_domain>.

This DNS A/AAAA or CNAME record must point to the load balancer for the control plane machines. This record must be resolvable from all the nodes within the cluster.

The API server must be able to resolve the worker nodes by the host names that are recorded in Kubernetes. If it cannot resolve the node names, proxied API calls can fail, and you cannot retrieve logs from pods.

Routes

*.apps.<cluster_name>.<base_domain>.

A wildcard DNS A/AAAA or CNAME record that points to the load balancer that targets the machines that run the Ingress router pods, which are the worker nodes by default. This record must be resolvable by both clients external to the cluster and from all the nodes within the cluster.

Generating an SSH private key and adding it to the agent

If you want to perform installation debugging or disaster recovery on your cluster, you must provide an SSH key to both your ssh-agent and the installation program. You can use this key to access the bootstrap machine in a public cluster to troubleshoot installation issues.

In a production environment, you require disaster recovery and debugging.

You can use this key to SSH into the master nodes as the user core. When you deploy the cluster, the key is added to the core user’s ~/.ssh/authorized_keys list.

You must use a local key, not one that you configured with platform-specific approaches such as AWS key pairs.

Procedure
  1. If you do not have an SSH key that is configured for password-less authentication on your computer, create one. For example, on a computer that uses a Linux operating system, run the following command:

    $ ssh-keygen -t rsa -b 4096 -N '' \
        -f <path>/<file_name> (1)
    1 Specify the path and file name, such as ~/.ssh/id_rsa, of the new SSH key.

    Running this command generates an SSH key that does not require a password in the location that you specified.

  2. Start the ssh-agent process as a background task:

    $ eval "$(ssh-agent -s)"
    Example output
    Agent pid 31874
  3. Add your SSH private key to the ssh-agent:

    $ ssh-add <path>/<file_name> (1)
    Example output
    Identity added: /home/<you>/<path>/<file_name> (<computer_name>)
    1 Specify the path and file name for your SSH private key, such as ~/.ssh/id_rsa
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 a local computer.

Prerequisites
  • A computer that runs Linux or macOS, with 500 MB of local disk space

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 both the installation program and the files that the installation program creates after you finish installing 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. From the Pull Secret page on the Red Hat OpenShift Cluster Manager site, download your installation pull secret as a .txt file. 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.

Manually creating the installation configuration file

For installations of OKD that use user-provisioned infrastructure, you manually generate your installation configuration file.

Prerequisites
  • Obtain the OKD installation program and the access token for your cluster.

Procedure
  1. Create an installation directory to store your required installation assets in:

    $ mkdir <installation_directory>

    You must create a directory. Some installation assets, like bootstrap X.509 certificates have short expiration intervals, so 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. Customize the following install-config.yaml file template and save it in the <installation_directory>.

    You must name this configuration file install-config.yaml.

  3. Back up the install-config.yaml file so that you can use it to install multiple clusters.

    The install-config.yaml file is consumed during the next step of the installation process. You must back it up now.

Sample install-config.yaml file for VMware vSphere

You can customize the install-config.yaml file to specify more details about your OKD cluster’s platform or modify the values of the required parameters.

apiVersion: v1
baseDomain: example.com (1)
compute:
- hyperthreading: Enabled  (2) (3)
  name: worker
  replicas: 0 (4)
controlPlane:
  hyperthreading: Enabled  (2) (3)
  name: master
  replicas: 3 (5)
metadata:
  name: test (6)
platform:
  vsphere:
    vcenter: your.vcenter.server (7)
    username: username (8)
    password: password (9)
    datacenter: datacenter (10)
    defaultDatastore: datastore (11)
    folder: "/<datacenter_name>/vm/<folder_name>/<subfolder_name>" (12)
fips: false (13)
pullSecret: '{"auths": ...}' (14)
sshKey: 'ssh-ed25519 AAAA...' (15)
1 The base domain of the cluster. All DNS records must be sub-domains of this base and include the cluster name.
2 The controlPlane section is a single mapping, but the compute section is a sequence of mappings. To meet the requirements of the different data structures, the first line of the compute section must begin with a hyphen, -, and the first line of the controlPlane section must not. Although both sections currently define a single machine pool, it is possible that future versions of OKD will support defining multiple compute pools during installation. Only one control plane pool is used.
3 Whether to enable or disable simultaneous multithreading, or hyperthreading. By default, simultaneous multithreading is enabled to increase the performance of your machines' cores. You can disable it by setting the parameter value to Disabled. If you disable simultaneous multithreading in some cluster machines, you must disable it in all cluster machines.

If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance. Your machines must use at least 8 CPUs and 32 GB of RAM if you disable simultaneous multithreading.

4 You must set the value of the replicas parameter to 0. This parameter controls the number of workers that the cluster creates and manages for you, which are functions that the cluster does not perform when you use user-provisioned infrastructure. You must manually deploy worker machines for the cluster to use before you finish installing OKD.
5 The number of control plane machines that you add to the cluster. Because the cluster uses this values as the number of etcd endpoints in the cluster, the value must match the number of control plane machines that you deploy.
6 The cluster name that you specified in your DNS records.
7 The fully-qualified host name or IP address of the vCenter server.
8 The name of the user for accessing the server. This user must have at least the roles and privileges that are required for static or dynamic persistent volume provisioning in vSphere.
9 The password associated with the vSphere user.
10 The vSphere datacenter.
11 The default vSphere datastore to use.
12 Optional: For installer-provisioned infrastructure, the absolute path of an existing folder where the installation program creates the virtual machines, for example, /<datacenter_name>/vm/<folder_name>/<subfolder_name>. If you do not provide this value, the installation program creates a top-level folder in the datacenter virtual machine folder that is named with the infrastructure ID. If you are providing the infrastructure for the cluster, omit this parameter.
13 Whether to enable or disable FIPS mode. By default, FIPS mode is not enabled. If FIPS mode is enabled, the Fedora CoreOS (FCOS) machines that OKD runs on bypass the default Kubernetes cryptography suite and use the cryptography modules that are provided with FCOS instead.
14 The pull secret that you obtained from the Pull Secret page on the Red Hat OpenShift Cluster Manager site. 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.
15 The public portion of the default SSH key for the core user in Fedora CoreOS (FCOS).

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.

Network configuration parameters

You can modify your cluster network configuration parameters in the install-config.yaml configuration file. The following table describes the parameters.

You cannot modify these parameters in the install-config.yaml file after installation.

Table 7. Required network parameters
Parameter Description Value

networking.networkType

The default Container Network Interface (CNI) network provider plug-in to deploy.

Either OpenShiftSDN or OVNKubernetes. The default value is OVNKubernetes.

networking.clusterNetwork[].cidr

A block of IP addresses from which Pod IP addresses are allocated. The OpenShiftSDN network plug-in supports multiple cluster networks. The address blocks for multiple cluster networks must not overlap. Select address pools large enough to fit your anticipated workload.

An IP address allocation in CIDR format. The default value is 10.128.0.0/14.

networking.clusterNetwork[].hostPrefix

The subnet prefix length to assign to each individual node. For example, if hostPrefix is set to 23, then each node is assigned a /23 subnet out of the given cidr, allowing for 510 (2^(32 - 23) - 2) Pod IP addresses.

A subnet prefix. The default value is 23.

networking.serviceNetwork[]

A block of IP addresses for services. OpenShiftSDN allows only one serviceNetwork block. The address block must not overlap with any other network block.

An IP address allocation in CIDR format. The default value is 172.30.0.0/16.

networking.machineNetwork[].cidr

A block of IP addresses assigned to nodes created by the OKD installation program while installing the cluster. The address block must not overlap with any other network block. Multiple CIDR ranges may be specified.

An IP address allocation in CIDR format. The default value is 10.0.0.0/16.

Modifying advanced network configuration parameters

You can modify the advanced network configuration parameters only before you install the cluster. Advanced configuration customization lets you integrate your cluster into your existing network environment by specifying an MTU or VXLAN port, by allowing customization of kube-proxy settings, and by specifying a different mode for the openshiftSDNConfig parameter.

Modifying the OKD manifest files directly is not supported.

Prerequisites
  • Create the install-config.yaml file and complete any modifications to it.

  • Create the Ignition config files for your cluster.

Procedure
  1. Use the following command to create manifests:

    $ ./openshift-install create manifests --dir=<installation_directory> (1)
    1 For <installation_directory>, specify the name of the directory that contains the install-config.yaml file for your cluster.
  2. Create a file that is named cluster-network-03-config.yml in the <installation_directory>/manifests/ directory:

    $ touch <installation_directory>/manifests/cluster-network-03-config.yml (1)
    1 For <installation_directory>, specify the directory name that contains the manifests/ directory for your cluster.

    After creating the file, several network configuration files are in the manifests/ directory, as shown:

    $ ls <installation_directory>/manifests/cluster-network-*
    Example output
    cluster-network-01-crd.yml
    cluster-network-02-config.yml
    cluster-network-03-config.yml
  3. Open the cluster-network-03-config.yml file in an editor and enter a CR that describes the Operator configuration you want:

    apiVersion: operator.openshift.io/v1
    kind: Network
    metadata:
      name: cluster
    spec: (1)
      clusterNetwork:
      - cidr: 10.128.0.0/14
        hostPrefix: 23
      serviceNetwork:
      - 172.30.0.0/16
      defaultNetwork:
        type: OpenShiftSDN
        openshiftSDNConfig:
          mode: NetworkPolicy
          mtu: 1450
          vxlanPort: 4789
    1 The parameters for the spec parameter are only an example. Specify your configuration for the Cluster Network Operator in the CR.

    The CNO provides default values for the parameters in the CR, so you must specify only the parameters that you want to change.

  4. Save the cluster-network-03-config.yml file and quit the text editor.

  5. Optional: Back up the manifests/cluster-network-03-config.yml file. The installation program deletes the manifests/ directory when creating the cluster.

  6. Remove the Kubernetes manifest files that define the control plane machines and compute machineSets:

    $ rm -f openshift/99_openshift-cluster-api_master-machines-*.yaml openshift/99_openshift-cluster-api_worker-machineset-*.yaml

    Because you create and manage these resources yourself, you do not have to initialize them.

    • You can preserve the MachineSet files to create compute machines by using the machine API, but you must update references to them to match your environment.

Cluster Network Operator configuration

The configuration for the cluster network is specified as part of the Cluster Network Operator (CNO) configuration and stored in a CR object that is named cluster. The CR specifies the parameters for the Network API in the operator.openshift.io API group.

You can specify the cluster network configuration for your OKD cluster by setting the parameter values for the defaultNetwork parameter in the CNO CR. The following CR displays the default configuration for the CNO and explains both the parameters you can configure and the valid parameter values:

Cluster Network Operator CR
apiVersion: operator.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
  clusterNetwork: (1)
  - cidr: 10.128.0.0/14
    hostPrefix: 23
  serviceNetwork: (1)
  - 172.30.0.0/16
  defaultNetwork: (2)
    ...
  kubeProxyConfig: (3)
    iptablesSyncPeriod: 30s (4)
    proxyArguments:
      iptables-min-sync-period: (5)
      - 0s
1 Specified in the install-config.yaml file.
2 Configures the default Container Network Interface (CNI) network provider for the cluster network.
3 The parameters for this object specify the kube-proxy configuration. If you do not specify the parameter values, the Cluster Network Operator applies the displayed default parameter values. If you are using the OVN-Kubernetes default CNI network provider, the kube-proxy configuration has no effect.
4 The refresh period for iptables rules. The default value is 30s. Valid suffixes include s, m, and h and are described in the Go time package documentation.
Because of performance improvements introduced in OKD 4.3 and greater, adjusting the iptablesSyncPeriod parameter is no longer necessary.
5 The minimum duration before refreshing iptables rules. This parameter ensures that the refresh does not happen too frequently. Valid suffixes include s, m, and h and are described in the Go time package.

Configuration parameters for the OpenShift SDN default CNI network provider

The following YAML object describes the configuration parameters for the OpenShift SDN default Container Network Interface (CNI) network provider.

defaultNetwork:
  type: OpenShiftSDN (1)
  openshiftSDNConfig: (2)
    mode: NetworkPolicy (3)
    mtu: 1450 (4)
    vxlanPort: 4789 (5)
1 Specified in the install-config.yaml file.
2 Specify only if you want to override part of the OpenShift SDN configuration.
3 Configures the network isolation mode for OpenShift SDN. The allowed values are Multitenant, Subnet, or NetworkPolicy. The default value is NetworkPolicy.
4 The maximum transmission unit (MTU) for the VXLAN overlay network. This value is normally configured automatically, but if the nodes in your cluster do not all use the same MTU, then you must set this explicitly to 50 less than the smallest node MTU value.
5 The port to use for all VXLAN packets. The default value is 4789. If you are running in a virtualized environment with existing nodes that are part of another VXLAN network, then you might be required to change this. For example, when running an OpenShift SDN overlay on top of VMware NSX-T, you must select an alternate port for VXLAN, since both SDNs use the same default VXLAN port number.

On Amazon Web Services (AWS), you can select an alternate port for the VXLAN between port 9000 and port 9999.

Configuration parameters for the OVN-Kubernetes default CNI network provider

The following YAML object describes the configuration parameters for the OVN-Kubernetes default CNI network provider.

defaultNetwork:
  type: OVNKubernetes (1)
  ovnKubernetesConfig: (2)
    mtu: 1400 (3)
    genevePort: 6081 (4)
1 Specified in the install-config.yaml file.
2 Specify only if you want to override part of the OVN-Kubernetes configuration.
3 The MTU for the Geneve (Generic Network Virtualization Encapsulation) overlay network. This value is normally configured automatically, but if the nodes in your cluster do not all use the same MTU, then you must set this explicitly to 100 less than the smallest node MTU value.
4 The UDP port for the Geneve overlay network.

Cluster Network Operator example configuration

A complete CR object for the CNO is displayed in the following example:

Cluster Network Operator example CR
apiVersion: operator.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
  clusterNetwork:
  - cidr: 10.128.0.0/14
    hostPrefix: 23
  serviceNetwork:
  - 172.30.0.0/16
  defaultNetwork:
    type: OpenShiftSDN
    openshiftSDNConfig:
      mode: NetworkPolicy
      mtu: 1450
      vxlanPort: 4789
  kubeProxyConfig:
    iptablesSyncPeriod: 30s
    proxyArguments:
      iptables-min-sync-period:
      - 0s

Creating the Ignition config files

Because you must manually start the cluster machines, you must generate the Ignition config files that the cluster needs to make its machines.

The Ignition config files that the installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending node-bootstrapper certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information.

Prerequisites
  • Obtain the OKD installation program and the pull secret for your cluster.

Procedure
  • Obtain the Ignition config files:

    $ ./openshift-install create ignition-configs --dir=<installation_directory> (1)
    1 For <installation_directory>, specify the directory name to store the files that the installation program creates.

    If you created an install-config.yaml file, specify the directory that contains it. Otherwise, specify an empty directory. Some installation assets, like bootstrap X.509 certificates have short expiration intervals, so 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.

    The following files are generated in the directory:

    .
    ├── auth
    │   ├── kubeadmin-password
    │   └── kubeconfig
    ├── bootstrap.ign
    ├── master.ign
    ├── metadata.json
    └── worker.ign

Extracting the infrastructure name

Prerequisites
  • Obtain the OKD installation program and the pull secret for your cluster.

  • Generate the Ignition config files for your cluster.

  • Install the jq package.

Procedure
  • To extract and view the infrastructure name from the Ignition config file metadata, run the following command:

    $ jq -r .infraID <installation_directory>/metadata.json (1)
    1 For <installation_directory>, specify the path to the directory that you stored the installation files in.
    Example output
    openshift-vw9j6 (1)
    
    1 The output of this command is your cluster name and a random string.

Creating Fedora CoreOS (FCOS) machines in vSphere

Before you install a cluster that contains user-provisioned infrastructure on VMware vSphere, you must create FCOS machines on vSphere hosts for it to use.

Prerequisites
  • Obtain the Ignition config files for your cluster.

  • Have access to an HTTP server that you can access from your computer and that the machines that you create can access.

  • Create a vSphere cluster.

Procedure
  1. Upload the bootstrap Ignition config file, which is named <installation_directory>/bootstrap.ign, that the installation program created to your HTTP server. Note the URL of this file.

    You must host the bootstrap Ignition config file because it is too large to fit in a vApp property.

  2. Save the following secondary Ignition config file for your bootstrap node to your computer as <installation_directory>/append-bootstrap.ign.

    {
      "ignition": {
        "config": {
          "merge": [
            {
              "source": "<bootstrap_ignition_config_url>", (1)
              "verification": {}
            }
          ]
        },
        "timeouts": {},
        "version": "3.0.0"
      },
      "networkd": {},
      "passwd": {},
      "storage": {},
      "systemd": {}
    }
    1 Specify the URL of the bootstrap Ignition config file that you hosted.

    When you create the Virtual Machine (VM) for the bootstrap machine, you use this Ignition config file.

  3. Convert the master, worker, and secondary bootstrap Ignition config files to Base64 encoding.

    For example, if you use a Linux operating system, you can use the base64 command to encode the files.

    $ base64 -w0 <installation_directory>/master.ign > <installation_directory>/master.64
    $ base64 -w0 <installation_directory>/worker.ign > <installation_directory>/worker.64
    $ base64 -w0 <installation_directory>/append-bootstrap.ign > <installation_directory>/append-bootstrap.64

    If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.

  4. Obtain the FCOS images from the FCOS Downloads page

  5. In the vSphere Client, create a folder in your datacenter to store your VMs.

    1. Click the VMs and Templates view.

    2. Right-click the name of your datacenter.

    3. Click New FolderNew VM and Template Folder.

    4. In the window that is displayed, enter the folder name. If you did not specify an existing folder in the install-config.yaml file, then create a folder with the same name as the infrastructure ID.

  6. In the vSphere Client, create a template for the OVA image.

    In the following steps, you use the same template for all of your cluster machines and provide the location for the Ignition config file for that machine type when you provision the VMs.

    1. From the Hosts and Clusters tab, right-click your cluster’s name and click Deploy OVF Template.

    2. On the Select an OVF tab, specify the name of the FCOS OVA file that you downloaded.

    3. On the Select a name and folder tab, set a Virtual machine name, such as FCOS, click the name of your vSphere cluster, and select the folder you created in the previous step.

    4. On the Select a compute resource tab, click the name of your vSphere cluster.

    5. On the Select storage tab, configure the storage options for your VM.

      • Select Thin Provision or Thick Provision, based on your storage preferences.

      • Select the datastore that you specified in your install-config.yaml file.

    6. On the Select network tab, specify the network that you configured for the cluster, if available.

    7. If you plan to use the same template for all cluster machine types, do not specify values on the Customize template tab.

      If you plan to add more compute machines to your cluster after you finish installation, do not delete this template.

  7. After the template deploys, deploy a VM for a machine in the cluster.

    1. Right-click the template’s name and click CloneClone to Virtual Machine.

    2. On the Select a name and folder tab, specify a name for the VM. You might include the machine type in the name, such as control-plane-0 or compute-1.

    3. On the Select a name and folder tab, select the name of the folder that you created for the cluster.

    4. On the Select a compute resource tab, select the name of a host in your datacenter.

    5. Optional: On the Select storage tab, customize the storage options.

    6. On the Select clone options, select Customize this virtual machine’s hardware.

    7. On the Customize hardware tab, click VM OptionsAdvanced.

      • Optional: In the event of cluster performance issues, from the Latency Sensitivity list, select High.

      • Click Edit Configuration, and on the Configuration Parameters window, click Add Configuration Params. Define the following parameter names and values:

        • guestinfo.ignition.config.data: Paste the contents of the base64-encoded Ignition config file for this machine type.

        • guestinfo.ignition.config.data.encoding: Specify base64.

        • disk.EnableUUID: Specify TRUE.

      • Alternatively, prior to powering on the virtual machine add via vApp properties:

        • Navigate to a virtual machine from the vCenter Server inventory.

        • On the Configure tab, expand Settings and select vApp options.

        • Scroll down and under Properties apply the configurations from above.

    8. In the Virtual Hardware panel of the Customize hardware tab, modify the specified values as required. Ensure that the amount of RAM, CPU, and disk storage meets the minimum requirements for the machine type.

    9. Complete the configuration and power on the VM.

  8. Create the rest of the machines for your cluster by following the preceding steps for each machine.

    You must create the bootstrap and control plane machines at this time. Because some pods are deployed on compute machines by default, also create at least two compute machines before you install the cluster.

Installing the CLI by downloading the binary

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

If you installed an earlier version of oc, you cannot use it to complete all of the commands in OKD 4. Download and install the new version of oc.

Installing the 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 xvzf <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 CLI, it is available using the oc command:

$ oc <command>

Installing the 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 CLI, it is available using the oc command:

C:\> oc <command>

Installing the 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 CLI, it is available using the oc command:

$ oc <command>

Creating the cluster

To create the OKD cluster, you wait for the bootstrap process to complete on the machines that you provisioned by using the Ignition config files that you generated with the installation program.

Prerequisites
  • Create the required infrastructure for the cluster.

  • You obtained the installation program and generated the Ignition config files for your cluster.

  • You used the Ignition config files to create FCOS machines for your cluster.

  • Your machines have direct internet access.

Procedure
  1. Monitor the bootstrap process:

    $ ./openshift-install --dir=<installation_directory> wait-for bootstrap-complete \ (1)
        --log-level=info (2)
    
    1 For <installation_directory>, specify the path to the directory that you stored the installation files in.
    2 To view different installation details, specify warn, debug, or error instead of info.
    Example output
    INFO Waiting up to 30m0s for the Kubernetes API at https://api.test.example.com:6443...
    INFO API v1.19.0 up
    INFO Waiting up to 30m0s for bootstrapping to complete...
    INFO It is now safe to remove the bootstrap resources

    The command succeeds when the Kubernetes API server signals that it has been bootstrapped on the control plane machines.

  2. After bootstrap process is complete, remove the bootstrap machine from the load balancer.

    You must remove the bootstrap machine from the load balancer at this point. You can also remove or reformat the machine itself.

Logging in to the cluster

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
  • Deploy an OKD cluster.

  • Install 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

Approving the CSRs for your machines

When you add machines to a cluster, two pending certificate signing requests (CSRs) are generated for each machine that you added. You must confirm that these CSRs are approved or, if necessary, approve them yourself.

Prerequisites
  • You added machines to your cluster.

Procedure
  1. Confirm that the cluster recognizes the machines:

    $ oc get nodes
    Example output
    NAME      STATUS    ROLES   AGE  VERSION
    master-0  Ready     master  63m  v1.19.0
    master-1  Ready     master  63m  v1.19.0
    master-2  Ready     master  64m  v1.19.0
    worker-0  NotReady  worker  76s  v1.19.0
    worker-1  NotReady  worker  70s  v1.19.0

    The output lists all of the machines that you created.

  2. Review the pending CSRs and ensure that you see a client and server request with the Pending or Approved status for each machine that you added to the cluster:

    $ oc get csr
    Example output
    NAME        AGE     REQUESTOR                                                                   CONDITION
    csr-8b2br   15m     system:serviceaccount:openshift-machine-config-operator:node-bootstrapper   Pending (1)
    csr-8vnps   15m     system:serviceaccount:openshift-machine-config-operator:node-bootstrapper   Pending
    csr-bfd72   5m26s   system:node:ip-10-0-50-126.us-east-2.compute.internal                       Pending (2)
    csr-c57lv   5m26s   system:node:ip-10-0-95-157.us-east-2.compute.internal                       Pending
    ...
    1 A client request CSR.
    2 A server request CSR.

    In this example, two machines are joining the cluster. You might see more approved CSRs in the list.

  3. If the CSRs were not approved, after all of the pending CSRs for the machines you added are in Pending status, approve the CSRs for your cluster machines:

    Because the CSRs rotate automatically, approve your CSRs within an hour of adding the machines to the cluster. If you do not approve them within an hour, the certificates will rotate, and more than two certificates will be present for each node. You must approve all of these certificates. After you approve the initial CSRs, the subsequent node client CSRs are automatically approved by the cluster kube-controller-manager. You must implement a method of automatically approving the kubelet serving certificate requests.

    • To approve them individually, run the following command for each valid CSR:

      $ oc adm certificate approve <csr_name> (1)
      1 <csr_name> is the name of a CSR from the list of current CSRs.
    • To approve all pending CSRs, run the following command:

      $ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs oc adm certificate approve
Additional information

Initial Operator configuration

After the control plane initializes, you must immediately configure some Operators so that they all become available.

Prerequisites
  • Your control plane has initialized.

Procedure
  1. Watch the cluster components come online:

    $ watch -n5 oc get clusteroperators
    Example output
    NAME                                       VERSION AVAILABLE   PROGRESSING   DEGRADED   SINCE
    authentication                             4.6.0   True        False         False      3h56m
    cloud-credential                           4.6.0   True        False         False      29h
    cluster-autoscaler                         4.6.0   True        False         False      29h
    config-operator                            4.6.0   True        False         False      6h39m
    console                                    4.6.0   True        False         False      3h59m
    csi-snapshot-controller                    4.6.0   True        False         False      4h12m
    dns                                        4.6.0   True        False         False      4h15m
    etcd                                       4.6.0   True        False         False      29h
    image-registry                             4.6.0   True        False         False      3h59m
    ingress                                    4.6.0   True        False         False      4h30m
    insights                                   4.6.0   True        False         False      29h
    kube-apiserver                             4.6.0   True        False         False      29h
    kube-controller-manager                    4.6.0   True        False         False      29h
    kube-scheduler                             4.6.0   True        False         False      29h
    kube-storage-version-migrator              4.6.0   True        False         False      4h2m
    machine-api                                4.6.0   True        False         False      29h
    machine-approver                           4.6.0   True        False         False      6h34m
    machine-config                             4.6.0   True        False         False      3h56m
    marketplace                                4.6.0   True        False         False      4h2m
    monitoring                                 4.6.0   True        False         False      6h31m
    network                                    4.6.0   True        False         False      29h
    node-tuning                                4.6.0   True        False         False      4h30m
    openshift-apiserver                        4.6.0   True        False         False      3h56m
    openshift-controller-manager               4.6.0   True        False         False      4h36m
    openshift-samples                          4.6.0   True        False         False      4h30m
    operator-lifecycle-manager                 4.6.0   True        False         False      29h
    operator-lifecycle-manager-catalog         4.6.0   True        False         False      29h
    operator-lifecycle-manager-packageserver   4.6.0   True        False         False      3h59m
    service-ca                                 4.6.0   True        False         False      29h
    storage                                    4.6.0   True        False         False      4h30m
  2. Configure the Operators that are not available.

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.

The Prometheus console provides an ImageRegistryRemoved alert, for example:

"Image Registry has been removed. ImageStreamTags, BuildConfigs and DeploymentConfigs which reference ImageStreamTags may not work as expected. Please configure storage and update the config to Managed state by editing configs.imageregistry.operator.openshift.io."

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 PersistentVolume, 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 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.

Block storage volumes are supported but not recommended for use with image registry on production clusters. An installation where the registry is configured on block storage is not highly available because the registry cannot have more than one replica.

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:

      kind: PersistentVolumeClaim
      apiVersion: v1
      metadata:
        name: image-registry-storage (1)
      spec:
        accessModes:
        - ReadWriteOnce (2)
        resources:
          requests:
            storage: 100Gi (3)
      1 A unique name that represents the PersistentVolumeClaim.
      2 The access mode of the PersistentVolumeClaim. With ReadWriteOnce, the volume can be mounted with read and write permissions by a single node.
      3 The size of the PersistentVolumeClaim.
    2. Create the PersistentVolumeClaim from the file:

      $ oc create -f pvc.yaml
  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 Creating a custom PVC allows you to 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.

Completing installation on user-provisioned infrastructure

After you complete the Operator configuration, you can finish installing the cluster on infrastructure that you provide.

Prerequisites
  • Your control plane has initialized.

  • You have completed the initial Operator configuration.

Procedure
  1. Confirm that all the cluster components are online:

    $ watch -n5 oc get clusteroperators
    Example output
    NAME                                       VERSION AVAILABLE   PROGRESSING   DEGRADED   SINCE
    authentication                             4.6.0   True        False         False      3h56m
    cloud-credential                           4.6.0   True        False         False      29h
    cluster-autoscaler                         4.6.0   True        False         False      29h
    config-operator                            4.6.0   True        False         False      6h39m
    console                                    4.6.0   True        False         False      3h59m
    csi-snapshot-controller                    4.6.0   True        False         False      4h12m
    dns                                        4.6.0   True        False         False      4h15m
    etcd                                       4.6.0   True        False         False      29h
    image-registry                             4.6.0   True        False         False      3h59m
    ingress                                    4.6.0   True        False         False      4h30m
    insights                                   4.6.0   True        False         False      29h
    kube-apiserver                             4.6.0   True        False         False      29h
    kube-controller-manager                    4.6.0   True        False         False      29h
    kube-scheduler                             4.6.0   True        False         False      29h
    kube-storage-version-migrator              4.6.0   True        False         False      4h2m
    machine-api                                4.6.0   True        False         False      29h
    machine-approver                           4.6.0   True        False         False      6h34m
    machine-config                             4.6.0   True        False         False      3h56m
    marketplace                                4.6.0   True        False         False      4h2m
    monitoring                                 4.6.0   True        False         False      6h31m
    network                                    4.6.0   True        False         False      29h
    node-tuning                                4.6.0   True        False         False      4h30m
    openshift-apiserver                        4.6.0   True        False         False      3h56m
    openshift-controller-manager               4.6.0   True        False         False      4h36m
    openshift-samples                          4.6.0   True        False         False      4h30m
    operator-lifecycle-manager                 4.6.0   True        False         False      29h
    operator-lifecycle-manager-catalog         4.6.0   True        False         False      29h
    operator-lifecycle-manager-packageserver   4.6.0   True        False         False      3h59m
    service-ca                                 4.6.0   True        False         False      29h
    storage                                    4.6.0   True        False         False      4h30m

    When all of the cluster Operators are AVAILABLE, you can complete the installation.

  2. Monitor for cluster completion:

    $ ./openshift-install --dir=<installation_directory> wait-for install-complete (1)
    1 For <installation_directory>, specify the path to the directory that you stored the installation files in.
    Example output
    INFO Waiting up to 30m0s for the cluster to initialize...

    The command succeeds when the Cluster Version Operator finishes deploying the OKD cluster from Kubernetes API server.

    The Ignition config files that the installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending node-bootstrapper certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information.

  3. Confirm that the Kubernetes API server is communicating with the pods.

    1. To view a list of all pods, use the following command:

      $ oc get pods --all-namespaces
      Example output
      NAMESPACE                         NAME                                            READY   STATUS      RESTARTS   AGE
      openshift-apiserver-operator      openshift-apiserver-operator-85cb746d55-zqhs8   1/1     Running     1          9m
      openshift-apiserver               apiserver-67b9g                                 1/1     Running     0          3m
      openshift-apiserver               apiserver-ljcmx                                 1/1     Running     0          1m
      openshift-apiserver               apiserver-z25h4                                 1/1     Running     0          2m
      openshift-authentication-operator authentication-operator-69d5d8bf84-vh2n8        1/1     Running     0          5m
      ...
    2. View the logs for a Pod that is listed in the output of the previous command by using the following command:

      $ oc logs <pod_name> -n <namespace> (1)
      1 Specify the Pod name and namespace, as shown in the output of the previous command.

      If the Pod logs display, the Kubernetes API server can communicate with the cluster machines.

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.