From VA 5.1 a 2-Node cluster will no longer be a supported configuration, subsequently the option to provision this configuration will no longer be available.
To upgrade to 5.1 the cluster will first need to be converted to a “3+ Node” cluster configuration, or the cluster entirely removed, prior to an upgrade.
To upgrade to a “3+ Node” configuration, you will need to revert the existing nodes:
After reverting both nodes, you will then be able to configure the cluster again. Note that a “3+ Node” configuration is the default and no selection is available to change this:
Once the cluster is created with this new configuration, or removed, you may then update to 5.1
Please note that a minimum of 3 nodes is highly recommended, but is not required during provisioning - you may configure 2 nodes during the provisioning and should add a 3rd node as soon as possible for redundancy, or prior to performing an upgrade.