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OpenShift Requirements

Before deploying OpenShift using the Digital Rebar content pack, ensure your environment meets the following requirements.

Hardware Requirements

Control Plane Nodes

  • Quantity: 3 nodes (required for HA)
  • CPU: 4 vCPUs minimum per node
  • RAM: 16GB minimum per node
  • Storage: 100GB minimum per node

Worker Nodes

  • Quantity: 2 nodes minimum
  • CPU: 2 vCPUs minimum per node
  • RAM: 8GB minimum per node
  • Storage: 100GB minimum per node

Load Balancer Nodes

  • Quantity: 1 node minimum (2+ recommended for HA)
  • CPU: 2 vCPUs minimum per node
  • RAM: 4GB minimum per node
  • Storage: 20GB minimum per node

Network Requirements

Network Segments

All network segments must be unique and non-overlapping:

  1. Machine Network: 172.21.0.0/20 (default)

    • Must be routable within your infrastructure
    • Used for node communication

  2. Service Network: 172.30.0.0/16 (default)

    • Used internally by Kubernetes
    • Does not need to be routable

  3. Pod Network: 10.128.0.0/14 (default)

    • Used for container networking
    • Managed by OVN-Kubernetes

Required Ports

Load Balancer Ports

  • 6443/tcp: Kubernetes API
  • 22623/tcp: Machine Config Server
  • 80/tcp: HTTP traffic
  • 443/tcp: HTTPS traffic
  • 8443/tcp: HTTPS traffic (used by some services)

Node Ports

  • 2379-2380/tcp: etcd (control plane only)
  • 10250/tcp: Kubelet
  • 10257/tcp: kube-controller-manager
  • 10259/tcp: kube-scheduler
  • 9000-9999/tcp: Host level services
  • 30000-32767/tcp: NodePort service range

Software Requirements

Red Hat Requirements

Digital Rebar Requirements

  • Digital Rebar Platform (DRP) v4.14.0 or later
  • DRP Community Content Bundle v4.14.0 or later
  • Configured resource broker (typically pool-broker)

DNS Requirements

Either use DRP-managed DNS (default) or configure external DNS with the following records:

Record Type Name Value
A api.\(cluster_name.\)base_domain Load Balancer IP
A api-int.\(cluster_name.\)base_domain Load Balancer IP
A *.apps.\(cluster_name.\)base_domain Load Balancer IP
A \(node_name.\)cluster_name.$base_domain Node IP

Internet Access

Connected Installation

  • Access to Red Hat container registries
  • Access to Red Hat update repositories
  • Access to OpenShift mirror sites

Disconnected Installation

  • Local registry with mirrored OpenShift images
  • Local package repository
  • Configure using:
  • openshift/external-registry
  • openshift/external-registry-create
  • openshift/external-registry-update