Chapter 8. Installing a private cluster on AWS

To create a private cluster on Amazon Web Services (AWS), you must provide an existing private VPC and subnets to host the cluster. The installation program must also be able to resolve the DNS records that the cluster requires. The installation program configures the Ingress Operator and API server for access from only the private network.

The cluster still requires access to internet to access the AWS APIs.

The following items are not required or created when you install a private cluster:

The installation program does use the baseDomain that you specify to create a private Route 53 zone and the required records for the cluster. The cluster is configured so that the Operators do not create public records for the cluster and all cluster machines are placed in the private subnets that you specify.

The installation program no longer creates the following components:

If you use a custom VPC, you must correctly configure it and its subnets for the installation program and the cluster to use. See Create a VPC in the Amazon Web Services documentation for more information about AWS VPC console wizard configurations and creating and managing an AWS VPC.

The installation program cannot:

You must complete these tasks before you install the cluster. See VPC networking components and Route tables for your VPC for more information on configuring networking in an AWS VPC.

Your VPC must meet the following characteristics:

If you are working in a disconnected environment, you are unable to reach the public IP addresses for EC2, ELB, and S3 endpoints. Depending on the level to which you want to restrict internet traffic during the installation, the following configuration options are available:

Option 1: Create VPC endpoints

Create a VPC endpoint and attach it to the subnets that the clusters are using. Name the endpoints as follows:

With this option, network traffic remains private between your VPC and the required AWS services.

Option 2: Create a proxy without VPC endpoints

As part of the installation process, you can configure an HTTP or HTTPS proxy. With this option, internet traffic goes through the proxy to reach the required AWS services.

Option 3: Create a proxy with VPC endpoints

As part of the installation process, you can configure an HTTP or HTTPS proxy with VPC endpoints. Create a VPC endpoint and attach it to the subnets that the clusters are using. Name the endpoints as follows:

When configuring the proxy in the install-config.yaml file, add these endpoints to the noProxy field. With this option, the proxy prevents the cluster from accessing the internet directly. However, network traffic remains private between your VPC and the required AWS services.

To ensure that the subnets that you provide are suitable, the installation program confirms the following data:

If you destroy a cluster that uses an existing VPC, the VPC is not deleted. When you remove the OpenShift Container Platform cluster from a VPC, the kubernetes.io/cluster/.*: shared tag is removed from the subnets that it used.

Starting with OpenShift Container Platform 4.3, you do not need all of the permissions that are required for an installation program-provisioned infrastructure cluster to deploy a cluster. This change mimics the division of permissions that you might have at your company: some individuals can create different resource in your clouds than others. For example, you might be able to create application-specific items, like instances, buckets, and load balancers, but not networking-related components such as VPCs, subnets, or ingress rules.

The AWS credentials that you use when you create your cluster do not need the networking permissions that are required to make VPCs and core networking components within the VPC, such as subnets, routing tables, internet gateways, NAT, and VPN. You still need permission to make the application resources that the machines within the cluster require, such as ELBs, security groups, S3 buckets, and nodes.

If you deploy OpenShift Container Platform to an existing network, the isolation of cluster services is reduced in the following ways:

By default, the installation program creates and attaches security groups to control plane and compute machines. The rules associated with the default security groups cannot be modified.

However, you can apply additional existing AWS security groups, which are associated with your existing VPC, to control plane and compute machines. Applying custom security groups can help you meet the security needs of your organization, in such cases where you need to control the incoming or outgoing traffic of these machines.

As part of the installation process, you apply custom security groups by modifying the install-config.yaml file before deploying the cluster.

For more information, see "Applying existing AWS security groups to the cluster".

Each cluster machine must meet the following minimum requirements:

If an instance type for your platform meets the minimum requirements for cluster machines, it is supported to use in OpenShift Container Platform.

The following Amazon Web Services (AWS) instance types have been tested with OpenShift Container Platform.

The following Amazon Web Services (AWS) 64-bit ARM instance types have been tested with OpenShift Container Platform.

You can customize the installation configuration file (install-config.yaml) 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
credentialsMode: Mint 2
controlPlane: 3 4
  hyperthreading: Enabled 5
  name: master
  platform:
    aws:
      zones:
      - us-west-2a
      - us-west-2b
      rootVolume:
        iops: 4000
        size: 500
        type: io1 6
      metadataService:
        authentication: Optional 7
      type: m6i.xlarge
  replicas: 3
compute: 8
- hyperthreading: Enabled 9
  name: worker
  platform:
    aws:
      rootVolume:
        iops: 2000
        size: 500
        type: io1 10
      metadataService:
        authentication: Optional 11
      type: c5.4xlarge
      zones:
      - us-west-2c
  replicas: 3
metadata:
  name: test-cluster 12
networking:
  clusterNetwork:
  - cidr: 10.128.0.0/14
    hostPrefix: 23
  machineNetwork:
  - cidr: 10.0.0.0/16
  networkType: OVNKubernetes 13
  serviceNetwork:
  - 172.30.0.0/16
platform:
  aws:
    region: us-west-2 14
    propagateUserTags: true 15
    userTags:
      adminContact: jdoe
      costCenter: 7536
    subnets: 16
    - subnet-1
    - subnet-2
    - subnet-3
    amiID: ami-0c5d3e03c0ab9b19a 17
    serviceEndpoints: 18
      - name: ec2
        url: https://vpce-id.ec2.us-west-2.vpce.amazonaws.com
    hostedZone: Z3URY6TWQ91KVV 19
fips: false 20
sshKey: ssh-ed25519 AAAA... 21
publish: Internal 22
pullSecret: '{"auths": ...}' 23

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.

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.

Applying existing AWS security groups to your control plane and compute machines can help you meet the security needs of your organization, in such cases where you need to control the incoming or outgoing traffic of these machines.

# ...
compute:
- hyperthreading: Enabled
  name: worker
  platform:
    aws:
      additionalSecurityGroupIDs:
        - sg-1 1
        - sg-2
  replicas: 3
controlPlane:
  hyperthreading: Enabled
  name: master
  platform:
    aws:
      additionalSecurityGroupIDs:
        - sg-3
        - sg-4
  replicas: 3
platform:
  aws:
    region: us-east-1
    subnets: 2
      - subnet-1
      - subnet-2
      - subnet-3

The Cloud Credential Operator (CCO) can be put into manual mode prior to installation in environments where the cloud identity and access management (IAM) APIs are not reachable, or the administrator prefers not to store an administrator-level credential secret in the cluster kube-system namespace.

To install a cluster that is configured to use the AWS Security Token Service (STS), you must configure the CCO utility and create the required AWS resources for your cluster.