Installing a cluster on VMC with user-provisioned infrastructure and network customizations

Setting up VMC for vSphere
- VMC Sizer tool
vSphere prerequisites
Internet access for OpenShift Container Platform
VMware vSphere infrastructure requirements
Requirements for a cluster with user-provisioned infrastructure
- Required machines
- Minimum resource requirements
- Certificate signing requests management
- Networking requirements for user-provisioned infrastructure
- User-provisioned DNS requirements
- Load balancing requirements for user-provisioned infrastructure
Preparing the user-provisioned infrastructure
Validating DNS resolution for user-provisioned infrastructure
Generating a key pair for cluster node SSH access
Obtaining the installation program
Manually creating the installation configuration file
- Sample install-config.yaml file for VMware vSphere
- Configuring the cluster-wide proxy during installation
Specifying advanced network configuration
Cluster Network Operator configuration
- Cluster Network Operator configuration object
Creating the Ignition config files
Extracting the infrastructure name
Installing RHCOS and starting the OpenShift Container Platform bootstrap process
Adding more compute machines to a cluster in vSphere
Disk partitioning
Updating the bootloader using bootupd
Waiting for the bootstrap process to complete
Logging in to the cluster by using the CLI
Approving the certificate signing requests for your machines
Initial Operator configuration
- Image registry removed during installation
- Image registry storage configuration
Completing installation on user-provisioned infrastructure
Backing up VMware vSphere volumes
Telemetry access for OpenShift Container Platform
Next steps

In OpenShift Container Platform version 4.8, you can install a cluster on your VMware vSphere instance using infrastructure you provision with customized network configuration options by deploying it to VMware Cloud (VMC) on AWS.

Once you configure your VMC environment for OpenShift Container Platform deployment, you use the OpenShift Container Platform installation program from the bastion management host, co-located in the VMC environment. The installation program and control plane automates the process of deploying and managing the resources needed for the OpenShift Container Platform cluster.

By customizing your network configuration, your cluster can coexist with existing IP address allocations in your environment and integrate with existing 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.

OpenShift Container Platform supports deploying a cluster to a single VMware vCenter only. Deploying a cluster with machines/machine sets on multiple vCenters is not supported.

Setting up VMC for vSphere

You can install OpenShift Container Platform on VMware Cloud (VMC) on AWS hosted vSphere clusters to enable applications to be deployed and managed both on-premise and off-premise, across the hybrid cloud.

You must configure several options in your VMC environment prior to installing OpenShift Container Platform on VMware vSphere. Ensure your VMC environment has the following prerequisites:

Create a non-exclusive, DHCP-enabled, NSX-T network segment and subnet. Other virtual machines (VMs) can be hosted on the subnet, but at least eight IP addresses must be available for the OpenShift Container Platform deployment.
Configure the following firewall rules:
- An ANY:ANY firewall rule between the OpenShift Container Platform compute network and the internet. This is used by nodes and applications to download container images.
- An ANY:ANY firewall rule between the installation host and the software-defined data center (SDDC) management network on port 443. This allows you to upload the Red Hat Enterprise Linux CoreOS (RHCOS) OVA during deployment.
- An HTTPS firewall rule between the OpenShift Container Platform compute network and vCenter. This connection allows OpenShift Container Platform to communicate with vCenter for provisioning and managing nodes, persistent volume claims (PVCs), and other resources.
You must have the following information to deploy OpenShift Container Platform:
- The OpenShift Container Platform cluster name, such as vmc-prod-1.
- The base DNS name, such as companyname.com.
- If not using the default, the pod network CIDR and services network CIDR must be identified, which are set by default to 10.128.0.0/14 and 172.30.0.0/16, respectively. These CIDRs are used for pod-to-pod and pod-to-service communication and are not accessible externally; however, they must not overlap with existing subnets in your organization.
- The following vCenter information:
  - vCenter hostname, username, and password
  - Datacenter name, such as SDDC-Datacenter
  - Cluster name, such as Cluster-1
  - Network name
  - Datastore name, such as WorkloadDatastore
    
    It is recommended to move your vSphere cluster to the VMC Compute-ResourcePool resource pool after your cluster installation is finished.
A Linux-based host deployed to VMC as a bastion.
- The bastion host can be Red Hat Enterprise Linux (RHEL) or any another Linux-based host; it must have internet connectivity and the ability to upload an OVA to the ESXi hosts.
- Download and install the OpenShift CLI tools to the bastion host.
  - The openshift-install installation program
  - The OpenShift CLI (oc) tool

You cannot use the VMware NSX Container Plugin for Kubernetes (NCP), and NSX is not used as the OpenShift SDN. The version of NSX currently available with VMC is incompatible with the version of NCP certified with OpenShift Container Platform.

However, the NSX DHCP service is used for virtual machine IP management with the full-stack automated OpenShift Container Platform deployment and with nodes provisioned, either manually or automatically, by the Machine API integration with vSphere. Additionally, NSX firewall rules are created to enable access with the OpenShift Container Platform cluster and between the bastion host and the VMC vSphere hosts.

VMC Sizer tool

VMware Cloud on AWS is built on top of AWS bare metal infrastructure; this is the same bare metal infrastructure which runs AWS native services. When a VMware cloud on AWS software-defined data center (SDDC) is deployed, you consume these physical server nodes and run the VMware ESXi hypervisor in a single tenant fashion. This means the physical infrastructure is not accessible to anyone else using VMC. It is important to consider how many physical hosts you will need to host your virtual infrastructure.

To determine this, VMware provides the VMC on AWS Sizer. With this tool, you can define the resources you intend to host on VMC:

Types of workloads
Total number of virtual machines
Specification information such as:
- Storage requirements
- vCPUs
- vRAM
- Overcommit ratios

With these details, the sizer tool can generate a report, based on VMware best practices, and recommend your cluster configuration and the number of hosts you will need.

vSphere prerequisites

You reviewed details about the OpenShift Container Platform installation and update processes.
You read the documentation on selecting a cluster installation method and preparing it for users.
You provisioned block registry storage. For more information on persistent storage, see Understanding persistent storage.
If you use a firewall, you configured it to allow the sites that your cluster requires access to.

Internet access for OpenShift Container Platform

In OpenShift Container Platform 4.8, you require access to the internet to install your cluster.

You must have internet access to:

Access OpenShift Cluster Manager to download the installation program and perform subscription management. If the cluster has internet access and you do not disable Telemetry, that service automatically entitles your cluster.
Access Quay.io to obtain the packages that are required to install your cluster.
Obtain the packages that are required to perform cluster updates.

If your cluster cannot have direct internet access, you can perform a restricted network installation on some types of infrastructure that you provision. During that process, you download the content that is required and use it to populate a mirror registry with the packages that you need to install a cluster and generate the installation program. With some installation types, the environment that you install your cluster in will not require internet access. Before you update the cluster, you update the content of the mirror registry.

VMware vSphere infrastructure requirements

You must install the OpenShift Container Platform 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 Red Hat Enterprise Linux CoreOS (RHCOS) supports. See the Red Hat Enterprise Linux 8 supported hypervisors list.
Storage with in-tree drivers	vSphere 6.5 and later	This plugin creates vSphere storage by using the in-tree storage drivers for vSphere included in OpenShift Container Platform.

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

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

Requirements for a cluster with user-provisioned infrastructure

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

This section describes the requirements for deploying OpenShift Container Platform on user-provisioned infrastructure.

Required machines

The smallest OpenShift Container Platform clusters require the following hosts:

Table 2. Minimum required hosts
Hosts	Description
One temporary bootstrap machine	The cluster requires the bootstrap machine to deploy the OpenShift Container Platform cluster on the three control plane machines. You can remove the bootstrap machine after you install the cluster.
Three control plane machines	The control plane machines run the Kubernetes and OpenShift Container Platform services that form the control plane.
At least two compute machines, which are also known as worker machines.	The workloads requested by OpenShift Container Platform users run on the compute machines.

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

The bootstrap and control plane machines must use Red Hat Enterprise Linux CoreOS (RHCOS) as the operating system. However, the compute machines can choose between Red Hat Enterprise Linux CoreOS (RHCOS) or Red Hat Enterprise Linux (RHEL) 7.9.

Note that RHCOS is based on Red Hat Enterprise Linux (RHEL) 8 and inherits all of its hardware certifications and requirements. See Red Hat Enterprise Linux technology capabilities and limits.

Minimum resource requirements

Each cluster machine must meet the following minimum requirements:

Table 3. Minimum resource requirements
Machine	Operating System	vCPU ^[1]	Virtual RAM	Storage	IOPS ^[2]
Bootstrap	RHCOS	4	16 GB	100 GB	300
Control plane	RHCOS	4	16 GB	100 GB	300
Compute	RHCOS or RHEL 7.9 ^[3]	2	8 GB	100 GB	300

One vCPU is equivalent to one physical core when simultaneous multithreading (SMT), or hyperthreading, is not enabled. When enabled, use the following formula to calculate the corresponding ratio: (threads per core × cores) × sockets = vCPUs.
OpenShift Container Platform and Kubernetes are sensitive to disk performance, and faster storage is recommended, particularly for etcd on the control plane nodes which require a 10 ms p99 fsync duration. Note that on many cloud platforms, storage size and IOPS scale together, so you might need to over-allocate storage volume to obtain sufficient performance.
As with all user-provisioned installations, if you choose to use RHEL 7 compute machines in your cluster, you take responsibility for all operating system life cycle management and maintenance, including performing system updates, applying patches, and completing all other required tasks. Use of RHEL 7 compute machines is deprecated and planned for removal in a future release of OpenShift Container Platform 4.

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.

Networking requirements for user-provisioned infrastructure

All the Red Hat Enterprise Linux CoreOS (RHCOS) machines require networking to be configured in initramfs during boot to fetch their Ignition config files.

During the initial boot, the machines require an IP address configuration that is set either through a DHCP server or statically by providing the required boot options. After a network connection is established, the machines download their Ignition config files from an HTTP or HTTPS server. The Ignition config files are then used to set the exact state of each machine. The Machine Config Operator completes more changes to the machines, such as the application of new certificates or keys, after installation.

It is recommended to use a DHCP server for long-term management of the cluster machines. Ensure that the DHCP server is configured to provide persistent IP addresses, DNS server information, and hostnames to the cluster machines.

If a DHCP service is not available for your user-provisioned infrastructure, you can instead provide the IP networking configuration and the address of the DNS server to the nodes at RHCOS install time. These can be passed as boot arguments if you are installing from an ISO image. See the Installing RHCOS and starting the OpenShift Container Platform bootstrap process section for more information about static IP provisioning and advanced networking options.

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.

Setting the cluster node hostnames through DHCP

On Red Hat Enterprise Linux CoreOS (RHCOS) machines, the hostname is set through NetworkManager. By default, the machines obtain their hostname through DHCP. If the hostname is not provided by DHCP, set statically through kernel arguments, or another method, it is obtained through a reverse DNS lookup. Reverse DNS lookup occurs after the network has been initialized on a node and can take time to resolve. Other system services can start prior to this and detect the hostname as localhost or similar. You can avoid this by using DHCP to provide the hostname for each cluster node.

Additionally, setting the hostnames through DHCP can bypass any manual DNS record name configuration errors in environments that have a DNS split-horizon implementation.

Network connectivity requirements

You must configure the network connectivity between machines to allow OpenShift Container Platform cluster components to communicate. Each machine must be able to resolve the hostnames of all other machines in the cluster.

This section provides details about the ports that are required.

In connected OpenShift Container Platform environments, all nodes are required to have internet access to pull images for platform containers and provide telemetry data to Red Hat.

Table 4. Ports used for all-machine to all-machine communications
Protocol	Port	Description
ICMP	N/A	Network reachability tests
TCP	`1936`	Metrics
	`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`.
	`500`	IPsec IKE packets
	`4500`	IPsec NAT-T packets
TCP/UDP	`30000`-`32767`	Kubernetes node port
ESP	N/A	IPsec Encapsulating Security Payload (ESP)

Table 5. Ports used for all-machine to control plane communications
Protocol	Port	Description
TCP	`6443`	Kubernetes API

Table 6. Ports used for control plane machine to control plane machine communications
Protocol	Port	Description
TCP	`2379`-`2380`	etcd server and peer ports

NTP configuration for user-provisioned infrastructure

OpenShift Container Platform clusters are configured to use a public Network Time Protocol (NTP) server by default. If you want to use a local enterprise NTP server, or if your cluster is being deployed in a disconnected network, you can configure the cluster to use a specific time server. For more information, see the documentation for Configuring chrony time service.

If a DHCP server provides NTP server information, the chrony time service on the Red Hat Enterprise Linux CoreOS (RHCOS) machines read the information and can sync the clock with the NTP servers.

User-provisioned DNS requirements

In OpenShift Container Platform deployments, DNS name resolution is required for the following components:

The Kubernetes API
The OpenShift Container Platform application wildcard
The bootstrap, control plane, and compute machines

Reverse DNS resolution is also required for the Kubernetes API, the bootstrap machine, the control plane machines, and the compute machines.

DNS A/AAAA or CNAME records are used for name resolution and PTR records are used for reverse name resolution. The reverse records are important because Red Hat Enterprise Linux CoreOS (RHCOS) uses the reverse records to set the hostnames for all the nodes, unless the hostnames are provided by DHCP. Additionally, the reverse records are used to generate the certificate signing requests (CSR) that OpenShift Container Platform needs to operate.

It is recommended to use a DHCP server to provide the hostnames to each cluster node. See the DHCP recommendations for user-provisioned infrastructure section for more information.

The following DNS records are required for a user-provisioned OpenShift Container Platform cluster and they must be in place before installation. In each record, <cluster_name> is the cluster name and <base_domain> is the base domain that you specify in the install-config.yaml file. A complete DNS record takes the form: <component>.<cluster_name>.<base_domain>..

Component Record Description

Kubernetes API

api.<cluster_name>.<base_domain>.

A DNS A/AAAA or CNAME record, and a DNS PTR record, to identify the API load balancer. These records must be resolvable by both clients external to the cluster and from all the nodes within the cluster.

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

A DNS A/AAAA or CNAME record, and a DNS PTR record, to internally identify the API load balancer. These records must be resolvable from all the nodes within the cluster.

The API server must be able to resolve the worker nodes by the hostnames that are recorded in Kubernetes. If the API server cannot resolve the node names, then 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 refers to the application ingress load balancer. The application ingress load balancer targets the machines that run the Ingress Controller pods. The Ingress Controller pods run on the compute machines by default. These records must be resolvable by both clients external to the cluster and from all the nodes within the cluster.

For example, console-openshift-console.apps.<cluster_name>.<base_domain> is used as a wildcard route to the OpenShift Container Platform console.

Bootstrap machine

bootstrap.<cluster_name>.<base_domain>.

A DNS A/AAAA or CNAME record, and a DNS PTR record, to identify the bootstrap machine. These records must be resolvable by the nodes within the cluster.

Control plane machines

<master><n>.<cluster_name>.<base_domain>.

DNS A/AAAA or CNAME records and DNS PTR records to identify each machine for the control plane nodes (also known as the master nodes). These records must be resolvable by the nodes within the cluster.

Compute machines

<worker><n>.<cluster_name>.<base_domain>.

DNS A/AAAA or CNAME records and DNS PTR records to identify each machine for the worker nodes. These records must be resolvable by the nodes within the cluster.

In OpenShift Container Platform 4.4 and later, you do not need to specify etcd host and SRV records in your DNS configuration.

You can use the dig command to verify name and reverse name resolution. See the section on Validating DNS resolution for user-provisioned infrastructure for detailed validation steps.

Example DNS configuration for user-provisioned clusters

This section provides A and PTR record configuration samples that meet the DNS requirements for deploying OpenShift Container Platform on user-provisioned infrastructure. The samples are not meant to provide advice for choosing one DNS solution over another.

In the examples, the cluster name is ocp4 and the base domain is example.com.

Example DNS A record configuration for a user-provisioned cluster

The following example is a BIND zone file that shows sample A records for name resolution in a user-provisioned cluster.

Sample DNS zone database

$TTL 1W
@	IN	SOA	ns1.example.com.	root (
			2019070700	; serial
			3H		; refresh (3 hours)
			30M		; retry (30 minutes)
			2W		; expiry (2 weeks)
			1W )		; minimum (1 week)
	IN	NS	ns1.example.com.
	IN	MX 10	smtp.example.com.
;
;
ns1.example.com.		IN	A	192.168.1.5
smtp.example.com.		IN	A	192.168.1.5
;
helper.example.com.		IN	A	192.168.1.5
helper.ocp4.example.com.	IN	A	192.168.1.5
;
api.ocp4.example.com.		IN	A	192.168.1.5 (1)
api-int.ocp4.example.com.	IN	A	192.168.1.5 (2)
;
*.apps.ocp4.example.com.	IN	A	192.168.1.5 (3)
;
bootstrap.ocp4.example.com.	IN	A	192.168.1.96 (4)
;
master0.ocp4.example.com.	IN	A	192.168.1.97 (5)
master1.ocp4.example.com.	IN	A	192.168.1.98 (5)
master2.ocp4.example.com.	IN	A	192.168.1.99 (5)
;
worker0.ocp4.example.com.	IN	A	192.168.1.11 (6)
worker1.ocp4.example.com.	IN	A	192.168.1.7 (6)
;
;EOF

Provides name resolution for the Kubernetes API. The record refers to the IP address of the API load balancer.

Provides name resolution for the Kubernetes API. The record refers to the IP address of the API load balancer and is used for internal cluster communications.

Provides name resolution for the wildcard routes. The record refers to the IP address of the application ingress load balancer. The application ingress load balancer targets the machines that run the Ingress Controller pods. The Ingress Controller pods run on the compute machines by default.

In the example, the same load balancer is used for the Kubernetes API and application ingress traffic. In production scenarios, you can deploy the API and application ingress load balancers separately so that you can scale the load balancer infrastructure for each in isolation.

Provides name resolution for the bootstrap machine.

Provides name resolution for the control plane machines.

Provides name resolution for the compute machines.

Example DNS PTR record configuration for a user-provisioned cluster

The following example BIND zone file shows sample PTR records for reverse name resolution in a user-provisioned cluster.

Sample DNS zone database for reverse records

$TTL 1W
@	IN	SOA	ns1.example.com.	root (
			2019070700	; serial
			3H		; refresh (3 hours)
			30M		; retry (30 minutes)
			2W		; expiry (2 weeks)
			1W )		; minimum (1 week)
	IN	NS	ns1.example.com.
;
5.1.168.192.in-addr.arpa.	IN	PTR	api.ocp4.example.com. (1)
5.1.168.192.in-addr.arpa.	IN	PTR	api-int.ocp4.example.com. (2)
;
96.1.168.192.in-addr.arpa.	IN	PTR	bootstrap.ocp4.example.com. (3)
;
97.1.168.192.in-addr.arpa.	IN	PTR	master0.ocp4.example.com. (4)
98.1.168.192.in-addr.arpa.	IN	PTR	master1.ocp4.example.com. (4)
99.1.168.192.in-addr.arpa.	IN	PTR	master2.ocp4.example.com. (4)
;
11.1.168.192.in-addr.arpa.	IN	PTR	worker0.ocp4.example.com. (5)
7.1.168.192.in-addr.arpa.	IN	PTR	worker1.ocp4.example.com. (5)
;
;EOF

1	Provides reverse DNS resolution for the Kubernetes API. The PTR record refers to the record name of the API load balancer.
2	Provides reverse DNS resolution for the Kubernetes API. The PTR record refers to the record name of the API load balancer and is used for internal cluster communications.
3	Provides reverse DNS resolution for the bootstrap machine.
4	Provides reverse DNS resolution for the control plane machines.
5	Provides reverse DNS resolution for the compute machines.

A PTR record is not required for the OpenShift Container Platform application wildcard.

Load balancing requirements for user-provisioned infrastructure

Before you install OpenShift Container Platform, you must provision the API and application ingress load balancing infrastructure. In production scenarios, you can deploy the API and application ingress load balancers separately so that you can scale the load balancer infrastructure for each in isolation.

If you want to deploy the API and application ingress load balancers with a Red Hat Enterprise Linux (RHEL) instance, you must purchase the RHEL subscription separately.

The load balancing infrastructure must meet the following requirements:

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 8. 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.

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.

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

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

Table 9. Application ingress load balancer
Port	Back-end machines (pool members)	Internal	External	Description
`443`	The machines that run the Ingress Controller pods, compute, or worker, by default.	X	X	HTTPS traffic
`80`	The machines that run the Ingress Controller pods, compute, or worker, by default.	X	X	HTTP traffic
`1936`	The worker nodes that run the Ingress Controller pods, by default. You must configure the `/healthz/ready` endpoint for the ingress health check probe.	X	X	HTTP traffic

If you are deploying a three-node cluster with zero compute nodes, the Ingress Controller pods run on the control plane nodes. In three-node cluster deployments, you must configure your application ingress load balancer to route HTTP and HTTPS traffic to the control plane nodes.

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

Example load balancer configuration for user-provisioned clusters

This section provides an example API and application ingress load balancer configuration that meets the load balancing requirements for user-provisioned clusters. The sample is an /etc/haproxy/haproxy.cfg configuration for an HAProxy load balancer. The example is not meant to provide advice for choosing one load balancing solution over another.

In the example, the same load balancer is used for the Kubernetes API and application ingress traffic. In production scenarios you can deploy the API and application ingress load balancers separately so that you can scale the load balancer infrastructure for each in isolation.

Sample API and application ingress load balancer configuration

global
  log         127.0.0.1 local2
  pidfile     /var/run/haproxy.pid
  maxconn     4000
  daemon
defaults
  mode                    http
  log                     global
  option                  dontlognull
  option http-server-close
  option                  redispatch
  retries                 3
  timeout http-request    10s
  timeout queue           1m
  timeout connect         10s
  timeout client          1m
  timeout server          1m
  timeout http-keep-alive 10s
  timeout check           10s
  maxconn                 3000
frontend stats
  bind *:1936
  mode            http
  log             global
  maxconn 10
  stats enable
  stats hide-version
  stats refresh 30s
  stats show-node
  stats show-desc Stats for ocp4 cluster (1)
  stats auth admin:ocp4
  stats uri /stats
listen api-server-6443 (2)
  bind *:6443
  mode tcp
  server bootstrap bootstrap.ocp4.example.com:6443 check inter 1s backup (3)
  server master0 master0.ocp4.example.com:6443 check inter 1s
  server master1 master1.ocp4.example.com:6443 check inter 1s
  server master2 master2.ocp4.example.com:6443 check inter 1s
listen machine-config-server-22623 (4)
  bind *:22623
  mode tcp
  server bootstrap bootstrap.ocp4.example.com:22623 check inter 1s backup (3)
  server master0 master0.ocp4.example.com:22623 check inter 1s
  server master1 master1.ocp4.example.com:22623 check inter 1s
  server master2 master2.ocp4.example.com:22623 check inter 1s
listen ingress-router-443 (5)
  bind *:443
  mode tcp
  balance source
  server worker0 worker0.ocp4.example.com:443 check inter 1s
  server worker1 worker1.ocp4.example.com:443 check inter 1s
listen ingress-router-80 (6)
  bind *:80
  mode tcp
  balance source
  server worker0 worker0.ocp4.example.com:80 check inter 1s
  server worker1 worker1.ocp4.example.com:80 check inter 1s

1 In the example, the cluster name is ocp4.

2 Port 6443 handles the Kubernetes API traffic and points to the control plane machines.

3 The bootstrap entries must be in place before the OpenShift Container Platform cluster installation and they must be removed after the bootstrap process is complete.

4 Port 22623 handles the machine config server traffic and points to the control plane machines.

5 Port 443 handles the HTTPS traffic and points to the machines that run the Ingress Controller pods. The Ingress Controller pods run on the compute machines by default.

Port 80 handles the HTTP traffic and points to the machines that run the Ingress Controller pods. The Ingress Controller pods run on the compute machines by default.

If you are using HAProxy as a load balancer, you can check that the haproxy process is listening on ports 6443, 22623, 443, and 80 by running netstat -nltupe on the HAProxy node.

If you are using HAProxy as a load balancer and SELinux is set to enforcing, you must ensure that the HAProxy service can bind to the configured TCP port by running setsebool -P haproxy_connect_any=1.

Preparing the user-provisioned infrastructure

Before you install OpenShift Container Platform on user-provisioned infrastructure, you must prepare the underlying infrastructure.

This section provides details about the high-level steps required to set up your cluster infrastructure in preparation for an OpenShift Container Platform installation. This includes configuring IP networking and network connectivity for your cluster nodes, enabling the required ports through your firewall, and setting up the required DNS and load balancing infrastructure.

After preparation, your cluster infrastructure must meet the requirements outlined in the Requirements for a cluster with user-provisioned infrastructure section.

Prerequisites

You have reviewed the OpenShift Container Platform 4.x Tested Integrations page.
You have reviewed the infrastructure requirements detailed in the Requirements for a cluster with user-provisioned infrastructure section.

Procedure

If you are using DHCP to provide the IP networking configuration to your cluster nodes, configure your DHCP service.

Add persistent IP addresses for the nodes to your DHCP server configuration. In your configuration, match the MAC address of the relevant network interface to the intended IP address for each node.

When you use DHCP to configure IP addressing for the cluster machines, the machines also obtain the DNS server information through DHCP. Define the persistent DNS server address that is used by the cluster nodes through your DHCP server configuration.

If you are not using a DHCP service, you must provide the IP networking configuration and the address of the DNS server to the nodes at RHCOS install time. These can be passed as boot arguments if you are installing from an ISO image. See the Installing RHCOS and starting the OpenShift Container Platform bootstrap process section for more information about static IP provisioning and advanced networking options.

Define the hostnames of your cluster nodes in your DHCP server configuration. See the Setting the cluster node hostnames through DHCP section for details about hostname considerations.

If you are not using a DHCP service, the cluster nodes obtain their hostname through a reverse DNS lookup.

Ensure that your network infrastructure provides the required network connectivity between the cluster components. See the Networking requirements for user-provisioned infrastructure section for details about the requirements.
Configure your firewall to enable the ports required for the OpenShift Container Platform cluster components to communicate. See Networking requirements for user-provisioned infrastructure section for details about the ports that are required.
Setup the required DNS infrastructure for your cluster.
1. Configure DNS name resolution for the Kubernetes API, the application wildcard, the bootstrap machine, the control plane machines, and the compute machines.
2. Configure reverse DNS resolution for the Kubernetes API, the bootstrap machine, the control plane machines, and the compute machines.
  
  See the User-provisioned DNS requirements section for more information about the OpenShift Container Platform DNS requirements.
Validate your DNS configuration.
1. From your installation node, run DNS lookups against the record names of the Kubernetes API, the wildcard routes, and the cluster nodes. Validate that the IP addresses in the responses correspond to the correct components.
2. From your installation node, run reverse DNS lookups against the IP addresses of the load balancer and the cluster nodes. Validate that the record names in the responses correspond to the correct components.
  
  See the Validating DNS resolution for user-provisioned infrastructure section for detailed DNS validation steps.
Provision the required API and application ingress load balancing infrastructure. See the Load balancing requirements for user-provisioned infrastructure section for more information about the requirements.

Some load balancing solutions require the DNS name resolution for the cluster nodes to be in place before the load balancing is initialized.

Validating DNS resolution for user-provisioned infrastructure

You can validate your DNS configuration before installing OpenShift Container Platform on user-provisioned infrastructure.

The validation steps detailed in this section must succeed before you install your cluster.

Prerequisites

You have configured the required DNS records for your user-provisioned infrastructure.

Procedure

From your installation node, run DNS lookups against the record names of the Kubernetes API, the wildcard routes, and the cluster nodes. Validate that the IP addresses contained in the responses correspond to the correct components.

Perform a lookup against the Kubernetes API record name. Check that the result points to the IP address of the API load balancer:
```
$ dig +noall +answer @<nameserver_ip> api.<cluster_name>.<base_domain> (1)
```
1 Replace <nameserver_ip> with the IP address of the nameserver, <cluster_name> with your cluster name, and <base_domain> with your base domain name.
Example output
```
api.ocp4.example.com.		0	IN	A	192.168.1.5
```
Perform a lookup against the Kubernetes internal API record name. Check that the result points to the IP address of the API load balancer:
```
$ dig +noall +answer @<nameserver_ip> api-int.<cluster_name>.<base_domain>
```
Example output
```
api-int.ocp4.example.com.		0	IN	A	192.168.1.5
```

Test an example *.apps.<cluster_name>.<base_domain> DNS wildcard lookup. All of the application wildcard lookups must resolve to the IP address of the application ingress load balancer:

$ dig +noall +answer @<nameserver_ip> random.apps.<cluster_name>.<base_domain>

Example output

random.apps.ocp4.example.com.		0	IN	A	192.168.1.5

In the example outputs, the same load balancer is used for the Kubernetes API and application ingress traffic. In production scenarios, you can deploy the API and application ingress load balancers separately so that you can scale the load balancer infrastructure for each in isolation.

You can replace random with another wildcard value. For example, you can query the route to the OpenShift Container Platform console:

$ dig +noall +answer @<nameserver_ip> console-openshift-console.apps.<cluster_name>.<base_domain>

Example output

console-openshift-console.apps.ocp4.example.com. 0 IN	A 192.168.1.5

Run a lookup against the bootstrap DNS record name. Check that the result points to the IP address of the bootstrap node:
```
$ dig +noall +answer @<nameserver_ip> bootstrap.<cluster_name>.<base_domain>
```
Example output
```
bootstrap.ocp4.example.com.		0	IN	A	192.168.1.96
```
Use this method to perform lookups against the DNS record names for the control plane and compute nodes. Check that the results correspond to the IP addresses of each node.

From your installation node, run reverse DNS lookups against the IP addresses of the load balancer and the cluster nodes. Validate that the record names contained in the responses correspond to the correct components.

Perform a reverse lookup against the IP address of the API load balancer. Check that the response includes the record names for the Kubernetes API and the Kubernetes internal API:

$ dig +noall +answer @<nameserver_ip> -x 192.168.1.5

Example output

5.1.168.192.in-addr.arpa. 0	IN	PTR	api-int.ocp4.example.com. (1)
5.1.168.192.in-addr.arpa. 0	IN	PTR	api.ocp4.example.com. (2)

1	Provides the record name for the Kubernetes internal API.
2	Provides the record name for the Kubernetes API.

A PTR record is not required for the OpenShift Container Platform application wildcard. No validation step is needed for reverse DNS resolution against the IP address of the application ingress load balancer.

Perform a reverse lookup against the IP address of the bootstrap node. Check that the result points to the DNS record name of the bootstrap node:
```
$ dig +noall +answer @<nameserver_ip> -x 192.168.1.96
```
Example output
```
96.1.168.192.in-addr.arpa. 0	IN	PTR	bootstrap.ocp4.example.com.
```
Use this method to perform reverse lookups against the IP addresses for the control plane and compute nodes. Check that the results correspond to the DNS record names of each node.

Generating a key pair for cluster node SSH access

During an OpenShift Container Platform installation, you can provide an SSH public key to the installation program. The key is passed to the Red Hat Enterprise Linux CoreOS (RHCOS) 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 RHCOS 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.

Do not skip this procedure in production environments, where disaster recovery and debugging is required.

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

Procedure

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 OpenShift Container Platform cluster that uses FIPS Validated / Modules in Process cryptographic libraries on the x86_64 architecture, do not create a key that uses the ed25519 algorithm. Instead, create a key that uses the rsa or ecdsa algorithm.

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
```
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.
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 OpenShift Container Platform, provide the SSH public key to the installation program.

Obtaining the installation program

Before you install OpenShift Container Platform, download the installation file on a local computer.

Prerequisites

You have a computer that runs Linux or macOS, with 500 MB of local disk space

Procedure

Access the Infrastructure Provider page on the OpenShift Cluster Manager site. If you have a Red Hat account, log in with your credentials. If you do not, create an account.
Select your infrastructure provider.

Navigate to the page for your installation type, download the installation program for your operating system, and place the file in the directory where you will store the installation configuration files.

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 OpenShift Container Platform uninstallation procedures for your specific cloud provider.

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
```
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 OpenShift Container Platform components.

Manually creating the installation configuration file

For user-provisioned installations of OpenShift Container Platform, you manually generate your installation configuration file.

Prerequisites

You have an SSH public key on your local machine to provide to the installation program. The key will be used for SSH authentication onto your cluster nodes for debugging and disaster recovery.
You have obtained the OpenShift Container Platform installation program and the pull secret for your cluster.

Procedure

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 OpenShift Container Platform version.

Customize the sample install-config.yaml file template that is provided and save it in the <installation_directory>.

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

For some platform types, you can alternatively run ./openshift-install create install-config --dir <installation_directory> to generate an install-config.yaml file. You can provide details about your cluster configuration at the prompts.

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 OpenShift Container Platform 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 OpenShift Container Platform will support defining multiple compute pools during installation. Only one control plane pool is used.

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 OpenShift Container Platform.

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 hostname 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.

Whether to enable or disable FIPS mode. By default, FIPS mode is not enabled. If FIPS mode is enabled, the Red Hat Enterprise Linux CoreOS (RHCOS) machines that OpenShift Container Platform runs on bypass the default Kubernetes cryptography suite and use the cryptography modules that are provided with RHCOS instead.

The use of FIPS Validated / Modules in Process cryptographic libraries is only supported on OpenShift Container Platform deployments on the x86_64 architecture.

14 The pull secret that you obtained from 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 OpenShift Container Platform components.

15 The public portion of the default SSH key for the core user in Red Hat Enterprise Linux CoreOS (RHCOS).

Configuring the cluster-wide proxy during installation

Production environments can deny direct access to the internet and instead have an HTTP or HTTPS proxy available. You can configure a new OpenShift Container Platform cluster to use a proxy by configuring the proxy settings in the install-config.yaml file.

Prerequisites

You have an existing install-config.yaml file.

You reviewed the sites that your cluster requires access to and determined whether any of them need to bypass the proxy. By default, all cluster egress traffic is proxied, including calls to hosting cloud provider APIs. You added sites to the Proxy object’s spec.noProxy field to bypass the proxy if necessary.

The Proxy object status.noProxy field is populated with the values of the networking.machineNetwork[].cidr, networking.clusterNetwork[].cidr, and networking.serviceNetwork[] fields from your installation configuration.

For installations on Amazon Web Services (AWS), Google Cloud Platform (GCP), Microsoft Azure, and Red Hat OpenStack Platform (RHOSP), the Proxy object status.noProxy field is also populated with the instance metadata endpoint (169.254.169.254).

Procedure

Edit your install-config.yaml file and add the proxy settings. For example:

apiVersion: v1
baseDomain: my.domain.com
proxy:
  httpProxy: http://<username>:<pswd>@<ip>:<port> (1)
  httpsProxy: https://<username>:<pswd>@<ip>:<port> (2)
  noProxy: example.com (3)
additionalTrustBundle: | (4)
    -----BEGIN CERTIFICATE-----
    <MY_TRUSTED_CA_CERT>
    -----END CERTIFICATE-----
...

1	A proxy URL to use for creating HTTP connections outside the cluster. The URL scheme must be `http`.
2	A proxy URL to use for creating HTTPS connections outside the cluster.
3	A comma-separated list of destination domain names, IP addresses, or other network CIDRs to exclude from proxying. Preface a domain with `.` to match subdomains only. For example, `.y.com` matches `x.y.com`, but not `y.com`. Use `*` to bypass the proxy for all destinations. You must include vCenter’s IP address and the IP range that you use for its machines.
4	If provided, the installation program generates a config map that is named `user-ca-bundle` in the `openshift-config` namespace to hold the additional CA certificates. If you provide `additionalTrustBundle` and at least one proxy setting, the `Proxy` object is configured to reference the `user-ca-bundle` config map in the `trustedCA` field. The Cluster Network Operator then creates a `trusted-ca-bundle` config map that merges the contents specified for the `trustedCA` parameter with the RHCOS trust bundle. The `additionalTrustBundle` field is required unless the proxy’s identity certificate is signed by an authority from the RHCOS trust bundle.

The installation program does not support the proxy readinessEndpoints field.

Save the file and reference it when installing OpenShift Container Platform.

The installation program creates a cluster-wide proxy that is named cluster that uses the proxy settings in the provided install-config.yaml file. If no proxy settings are provided, a cluster Proxy object is still created, but it will have a nil spec.

Only the Proxy object named cluster is supported, and no additional proxies can be created.

Specifying advanced network configuration

You can use advanced network configuration for your cluster network provider to integrate your cluster into your existing network environment. You can specify advanced network configuration only before you install the cluster.

Customizing your network configuration by modifying the OpenShift Container Platform manifest files created by the installation program is not supported. Applying a manifest file that you create, as in the following procedure, is supported.

Prerequisites

You have created the install-config.yaml file and completed any modifications to it.

Procedure

Change to the directory that contains the installation program and create the manifests:
```
$ ./openshift-install create manifests --dir <installation_directory> (1)
```
1 <installation_directory> specifies the name of the directory that contains the install-config.yaml file for your cluster.
Create a stub manifest file for the advanced network configuration that is named cluster-network-03-config.yml in the <installation_directory>/manifests/ directory:
```
apiVersion: operator.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
```

Specify the advanced network configuration for your cluster in the cluster-network-03-config.yml file, such as in the following examples:

Specify a different VXLAN port for the OpenShift SDN network provider

apiVersion: operator.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
  defaultNetwork:
    openshiftSDNConfig:
      vxlanPort: 4800

Enable IPsec for the OVN-Kubernetes network provider

apiVersion: operator.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
  defaultNetwork:
    ovnKubernetesConfig:
      ipsecConfig: {}

Optional: Back up the manifests/cluster-network-03-config.yml file. The installation program consumes the manifests/ directory when you create the Ignition config files.
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 custom resource (CR) object that is named cluster. The CR specifies the fields for the Network API in the operator.openshift.io API group.

The CNO configuration inherits the following fields during cluster installation from the Network API in the Network.config.openshift.io API group and these fields cannot be changed:

clusterNetwork: IP address pools from which pod IP addresses are allocated.
serviceNetwork: IP address pool for services.
defaultNetwork.type: Cluster network provider, such as OpenShift SDN or OVN-Kubernetes.

You can specify the cluster network provider configuration for your cluster by setting the fields for the defaultNetwork object in the CNO object named cluster.

Cluster Network Operator configuration object

The fields for the Cluster Network Operator (CNO) are described in the following table:

Table 10. Cluster Network Operator configuration object
Field	Type	Description
`metadata.name`	`string`	The name of the CNO object. This name is always `cluster`.
`spec.clusterNetwork`	`array`	A list specifying the blocks of IP addresses from which pod IP addresses are allocated and the subnet prefix length assigned to each individual node in the cluster. For example: `spec: clusterNetwork: - cidr: 10.128.0.0/19 hostPrefix: 23 - cidr: 10.128.32.0/19 hostPrefix: 23` You can customize this field only in the `install-config.yaml` file before you create the manifests. The value is read-only in the manifest file.
`spec.serviceNetwork`	`array`	A block of IP addresses for services. The OpenShift SDN and OVN-Kubernetes Container Network Interface (CNI) network providers support only a single IP address block for the service network. For example: `spec: serviceNetwork: - 172.30.0.0/14` You can customize this field only in the `install-config.yaml` file before you create the manifests. The value is read-only in the manifest file.
`spec.defaultNetwork`	`object`	Configures the Container Network Interface (CNI) cluster network provider for the cluster network.
`spec.kubeProxyConfig`	`object`	The fields for this object specify the kube-proxy configuration. If you are using the OVN-Kubernetes cluster network provider, the kube-proxy configuration has no effect.

defaultNetwork object configuration

The values for the defaultNetwork object are defined in the following table:

Field Type Description

type

string

Either OpenShiftSDN or OVNKubernetes. The cluster network provider is selected during installation. This value cannot be changed after cluster installation.

OpenShift Container Platform uses the OpenShift SDN Container Network Interface (CNI) cluster network provider by default.

openshiftSDNConfig

object

This object is only valid for the OpenShift SDN cluster network provider.

ovnKubernetesConfig

object

This object is only valid for the OVN-Kubernetes cluster network provider.

Configuration for the OpenShift SDN CNI cluster network provider

The following table describes the configuration fields for the OpenShift SDN Container Network Interface (CNI) cluster network provider.

Table 12. `openshiftSDNConfig` object
Field	Type	Description
`mode`	`string`	Configures the network isolation mode for OpenShift SDN. The default value is `NetworkPolicy`. The values `Multitenant` and `Subnet` are available for backwards compatibility with OpenShift Container Platform 3.x but are not recommended. This value cannot be changed after cluster installation.
`mtu`	`integer`	The maximum transmission unit (MTU) for the VXLAN overlay network. This is detected automatically based on the MTU of the primary network interface. You do not normally need to override the detected MTU. If the auto-detected value is not what you expect it to be, confirm that the MTU on the primary network interface on your nodes is correct. You cannot use this option to change the MTU value of the primary network interface on the nodes. If your cluster requires different MTU values for different nodes, you must set this value to `50` less than the lowest MTU value in your cluster. For example, if some nodes in your cluster have an MTU of `9001`, and some have an MTU of `1500`, you must set this value to `1450`. This value cannot be changed after cluster installation.
`vxlanPort`	`integer`	The port to use for all VXLAN packets. The default value is `4789`. This value cannot be changed after cluster installation. 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 the VXLAN, because 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`.

Example OpenShift SDN configuration

defaultNetwork:
  type: OpenShiftSDN
  openshiftSDNConfig:
    mode: NetworkPolicy
    mtu: 1450
    vxlanPort: 4789

Configuration for the OVN-Kubernetes CNI cluster network provider

The following table describes the configuration fields for the OVN-Kubernetes CNI cluster network provider.

Table 13. `ovnKubernetesConfig` object
Field	Type	Description
`mtu`	`integer`	The maximum transmission unit (MTU) for the Geneve (Generic Network Virtualization Encapsulation) overlay network. This is detected automatically based on the MTU of the primary network interface. You do not normally need to override the detected MTU. If the auto-detected value is not what you expect it to be, confirm that the MTU on the primary network interface on your nodes is correct. You cannot use this option to change the MTU value of the primary network interface on the nodes. If your cluster requires different MTU values for different nodes, you must set this value to `100` less than the lowest MTU value in your cluster. For example, if some nodes in your cluster have an MTU of `9001`, and some have an MTU of `1500`, you must set this value to `1400`. This value cannot be changed after cluster installation.
`genevePort`	`integer`	The port to use for all Geneve packets. The default value is `6081`. This value cannot be changed after cluster installation.
`ipsecConfig`	`object`	Specify an empty object to enable IPsec encryption. This value cannot be changed after cluster installation.
`policyAuditConfig`	`object`	Specify a configuration object for customizing network policy audit logging. If unset, the defaults audit log settings are used.

Table 14. `policyAuditConfig` object
Field	Type	Description
`rateLimit`	integer	The maximum number of messages to generate every second per node. The default value is `20` messages per second.
`maxFileSize`	integer	The maximum size for the audit log in bytes. The default value is `50000000` or 50 MB.
`destination`	string	One of the following additional audit log targets: `libc` The libc `syslog()` function of the journald process on the host. `udp:<host>:<port>` A syslog server. Replace `<host>:<port>` with the host and port of the syslog server. `unix:<file>` A Unix Domain Socket file specified by `<file>`. `null` Do not send the audit logs to any additional target.
`syslogFacility`	string	The syslog facility, such as `kern`, as defined by RFC5424. The default value is `local0`.

Example OVN-Kubernetes configuration

defaultNetwork:
  type: OVNKubernetes
  ovnKubernetesConfig:
    mtu: 1400
    genevePort: 6081
    ipsecConfig: {}

kubeProxyConfig object configuration

The values for the kubeProxyConfig object are defined in the following table:

Field Type Description

iptablesSyncPeriod

string

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 OpenShift Container Platform 4.3 and greater, adjusting the iptablesSyncPeriod parameter is no longer necessary.

proxyArguments.iptables-min-sync-period

array

The minimum duration before refreshing iptables rules. This field ensures that the refresh does not happen too frequently. Valid suffixes include s, m, and h and are described in the Go time package. The default value is:

kubeProxyConfig:
  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.
It is recommended that you use Ignition config files within 12 hours after they are generated because the 24-hour certificate rotates from 16 to 22 hours after the cluster is installed. By using the Ignition config files within 12 hours, you can avoid installation failure if the certificate update runs during installation.

Prerequisites

Obtain the OpenShift Container Platform installation program and the pull secret for your cluster. For a restricted network installation, these files are on your mirror host.

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 OpenShift Container Platform 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

The Ignition config files contain a unique cluster identifier that you can use to uniquely identify your cluster in VMware Cloud on AWS. If you plan to use the cluster identifier as the name of your virtual machine folder, you must extract it.

Prerequisites

You obtained the OpenShift Container Platform installation program and the pull secret for your cluster.
You generated the Ignition config files for your cluster.
You installed 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.

Setting up VMC for vSphere

VMC Sizer tool

vSphere prerequisites

Internet access for OpenShift Container Platform

VMware vSphere infrastructure requirements

Requirements for a cluster with user-provisioned infrastructure

Required machines

Minimum resource requirements

Certificate signing requests management

Networking requirements for user-provisioned infrastructure

Setting the cluster node hostnames through DHCP

Network connectivity requirements

NTP configuration for user-provisioned infrastructure

User-provisioned DNS requirements

Example DNS configuration for user-provisioned clusters

Load balancing requirements for user-provisioned infrastructure

Example load balancer configuration for user-provisioned clusters

Preparing the user-provisioned infrastructure

Validating DNS resolution for user-provisioned infrastructure

Generating a key pair for cluster node SSH access

Obtaining the installation program

Manually creating the installation configuration file

Sample install-config.yaml file for VMware vSphere

Configuring the cluster-wide proxy during installation

Specifying advanced network configuration

Cluster Network Operator configuration

Cluster Network Operator configuration object

defaultNetwork object configuration

Configuration for the OpenShift SDN CNI cluster network provider

Configuration for the OVN-Kubernetes CNI cluster network provider

kubeProxyConfig object configuration

Creating the Ignition config files

Extracting the infrastructure name

Sample `install-config.yaml` file for VMware vSphere