Experimental Tanzu CLI Features

This topic lists experimental features of the Tanzu CLI and explains how to activate them.

List of Experimental Features

The experimental features below are currently in development and intended for evaluation and test purposes only.

Feature Description
custom-nameservers Do not enable. Reserved for future use.
dual-stack-ipv4-primary (vSphere only) Allows you to deploy dual-stack clusters, with IPv4 as the primary protocol. For more information, see Dual-Stack Clusters below.
dual-stack-ipv6-primary Do not enable. Reserved for future use.
network-separation-beta Do not enable. Reserved for future use.

Activating and Deactivating Experimental Features

By default, experimental features are set to false in the Tanzu CLI:

  • To activate an experimental feature, run:

    tanzu config set features.PLUGIN.FEATURE true
    

    Where:

    • PLUGIN is the name of the CLI plugin. For example, cluster or management-cluster.
    • FEATURE is the name of the feature that you want to activate.
  • To deactivate an experimental feature, run:

    tanzu config set features.PLUGIN.FEATURE false
    

Dual-Stack Clusters

The dual-stack feature lets you deploy clusters with IPv4 and IPv6 IP families. However, the primary IP family is IPv4. Before experimenting with this feature, configure your vCenter Server to support both IPv4 and IPv6 connectivity.

The following are the limitations of the dual-stack feature in this release:

  • The dual-stack feature supports vSphere as the only infrastructure as a service (IaaS) product.

  • You cannot configure dual-stack on clusters with Photon OS nodes. Only clusters configured with an OS_NAME of ubuntu are supported.

  • You cannot configure dual-stack networking for vSphere with Tanzu Supervisor Clusters or the workload clusters that they create.

  • You cannot deploy a dual-stack management cluster with the installer interface.

  • You cannot use the dual-stack or the IPv6 services on the load balancer services provided by NSX Advanced Load Balancer (ALB). You can use kube-vip as the control plane endpoint provider for a dual-stack cluster. Using NSX ALB as the control plane endpoint provider for a dual-stack cluster has not been validated.

  • Only the core add-on components, such as Antrea, Calico, CSI, CPI, and Pinniped, have been validated for dual-stack support in this release.

To configure dual-stack on the clusters:

  1. Set the dual-stack feature flag:

    a. To enable the feature on the management cluster, run the following command:

    tanzu config set features.management-cluster.dual-stack-ipv4-primary true
    

    b. To enable the feature on the workload cluster, run the following command:

    tanzu config set features.cluster.dual-stack-ipv4-primary true
    
  2. Deploy Management Clusters or Deploy Tanzu Kubernetes Clusters, as required.

    In the cluster configuration file:

    • Set the IP family configuration variable TKG_IP_FAMILY: ipv4,ipv6.
    • Optionally, set the service CIDRs and cluster CIDRs.

      Note: There are two CIDRs for each variable. The IP families of these CIDRs follow the order of the configured TKG_IP_FAMILY. The largest CIDR range that is permitted for the IPv4 addresses is /12, and the largest IPv6 SERVICE_CIDR range is /108. If you do not set the CIDRs, the default values are used.

    • Set the following configuration file parameter, if you are using Antrea as the CNI for your cluster:

      ANTREA_ENDPOINTSLICES: true
      

    The services, which have an ipFamilyPolicy specified in their specs of PreferDualStack or RequireDualStack, can now be accessed through IPv4 or IPv6.

Note: The end-to-end tests for the dual-stack feature in upstream Kubernetes can fail as a cluster node advertises only its primary IP address (in this case, the IPv4 address) as its IP address.

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