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. |
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 |
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. |
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.
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.
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. |
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.
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. |
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.
The smallest OpenShift Container Platform clusters require the following 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.
Each cluster machine must meet the following minimum 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.
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.
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.
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.
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. |
Protocol | Port | Description |
---|---|---|
ICMP |
N/A |
Network reachability tests |
TCP |
|
Metrics |
|
Host level services, including the node exporter on ports |
|
|
The default ports that Kubernetes reserves |
|
|
openshift-sdn |
|
UDP |
|
VXLAN and Geneve |
|
VXLAN and Geneve |
|
|
Host level services, including the node exporter on ports |
|
|
IPsec IKE packets |
|
|
IPsec NAT-T packets |
|
TCP/UDP |
|
Kubernetes node port |
ESP |
N/A |
IPsec Encapsulating Security Payload (ESP) |
Protocol | Port | Description |
---|---|---|
TCP |
|
Kubernetes API |
Protocol | Port | Description |
---|---|---|
TCP |
|
etcd server and peer ports |
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.
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 |
|
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. |
|
|
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.
|
||
Routes |
|
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, |
|
Bootstrap machine |
|
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 |
|
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 |
|
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 |
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
.
The following example is a BIND zone file that shows sample A records for name resolution in a user-provisioned cluster.
$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
1 | Provides name resolution for the Kubernetes API. The record refers to the IP address of the API load balancer. | ||
2 | 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. | ||
3 | 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.
|
||
4 | Provides name resolution for the bootstrap machine. | ||
5 | Provides name resolution for the control plane machines. | ||
6 | Provides name resolution for the compute machines. |
The following example BIND zone file shows sample PTR records for reverse name resolution in a user-provisioned cluster.
$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. |
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:
Port | Back-end machines (pool members) | Internal | External | Description |
---|---|---|---|---|
|
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 |
X |
X |
Kubernetes API server |
|
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 |
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:
Port | Back-end machines (pool members) | Internal | External | Description |
---|---|---|---|---|
|
The machines that run the Ingress Controller pods, compute, or worker, by default. |
X |
X |
HTTPS traffic |
|
The machines that run the Ingress Controller pods, compute, or worker, by default. |
X |
X |
HTTP traffic |
|
The worker nodes that run the Ingress Controller pods, by default. You must configure the |
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. |
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. |
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. |
||
6 | 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 |
If you are using HAProxy as a load balancer and SELinux is set to |
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.
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.
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.
Configure DNS name resolution for the Kubernetes API, the application wildcard, the bootstrap machine, the control plane machines, and the compute machines.
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.
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.
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. |
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. |
You have configured the required DNS records for your user-provisioned infrastructure.
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. |
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>
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>
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>
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>
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
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
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.
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. |
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 |
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 |
If the ssh-agent
process is not already running for your local user, start it as a background task:
$ eval "$(ssh-agent -s)"
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 |
Identity added: /home/<you>/<path>/<file_name> (<computer_name>)
When you install OpenShift Container Platform, provide the SSH public key to the installation program.
Before you install OpenShift Container Platform, download the installation file on a local computer.
You have a computer that runs Linux or macOS, with 500 MB of local disk space
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.
For user-provisioned installations of OpenShift Container Platform, you manually generate your installation configuration file.
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.
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 |
For some platform types, you can alternatively run |
Back up the install-config.yaml
file so that you can use it to install
multiple clusters.
The |
install-config.yaml
file for VMware vSphereYou 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. |
||
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.
|
||
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. |
||
13 | 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.
|
||
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). |
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.
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 For installations on Amazon Web Services (AWS), Google Cloud Platform (GCP), Microsoft Azure, and Red Hat OpenStack Platform (RHOSP), the |
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 |
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 |
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. |
You have created the install-config.yaml
file and completed any modifications to it.
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:
apiVersion: operator.openshift.io/v1
kind: Network
metadata:
name: cluster
spec:
defaultNetwork:
openshiftSDNConfig:
vxlanPort: 4800
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.
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
.
The fields for the Cluster Network Operator (CNO) are described in the following table:
Field | Type | Description |
---|---|---|
|
|
The name of the CNO object. This name is always |
|
|
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:
You can customize this field only in the |
|
|
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:
You can customize this field only in the |
|
|
Configures the Container Network Interface (CNI) cluster network provider for the cluster network. |
|
|
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. |
The values for the defaultNetwork
object are defined in the following table:
Field | Type | Description | ||
---|---|---|---|---|
|
|
Either
|
||
|
|
This object is only valid for the OpenShift SDN cluster network provider. |
||
|
|
This object is only valid for the OVN-Kubernetes cluster network provider. |
The following table describes the configuration fields for the OpenShift SDN Container Network Interface (CNI) cluster network provider.
Field | Type | Description |
---|---|---|
|
|
Configures the network isolation mode for OpenShift SDN. The default value is The values |
|
|
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 This value cannot be changed after cluster installation. |
|
|
The port to use for all VXLAN packets. The default value is 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 |
defaultNetwork:
type: OpenShiftSDN
openshiftSDNConfig:
mode: NetworkPolicy
mtu: 1450
vxlanPort: 4789
The following table describes the configuration fields for the OVN-Kubernetes CNI cluster network provider.
Field | Type | Description |
---|---|---|
|
|
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 This value cannot be changed after cluster installation. |
|
|
The port to use for all Geneve packets. The default value is |
|
|
Specify an empty object to enable IPsec encryption. This value cannot be changed after cluster installation. |
|
|
Specify a configuration object for customizing network policy audit logging. If unset, the defaults audit log settings are used. |
Field | Type | Description |
---|---|---|
|
integer |
The maximum number of messages to generate every second per node. The default value is |
|
integer |
The maximum size for the audit log in bytes. The default value is |
|
string |
One of the following additional audit log targets:
|
|
string |
The syslog facility, such as |
defaultNetwork:
type: OVNKubernetes
ovnKubernetesConfig:
mtu: 1400
genevePort: 6081
ipsecConfig: {}
The values for the kubeProxyConfig
object are defined in the following table:
Field | Type | Description | ||
---|---|---|---|---|
|
|
The refresh period for
|
||
|
|
The minimum duration before refreshing
|
Because you must manually start the cluster machines, you must generate the Ignition config files that the cluster needs to make its machines.
|
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.
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 |
The following files are generated in the directory:
. ├── auth │ ├── kubeadmin-password │ └── kubeconfig ├── bootstrap.ign ├── master.ign ├── metadata.json └── worker.ign
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.
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.
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. |
openshift-vw9j6 (1)
1 | The output of this command is your cluster name and a random string. |