Chapter 1. Introduction

Supported virtualization platforms to which a Virtual Data Center (VDC) subscription can be applied are:

A VDC subscription applies only to a hypervisor’s guest virtual machines, not the hypervisor itself. For all virtualization platforms which require a Red Hat Enterprise Linux hypervisor, the hypervisor requires its own subscription.

Red Hat recommends a subscription that allows virtual machines to inherit subscriptions, since this allows for flexibility when provisioning virtual machines. However the choice is yours, and should be made according to your requirements. If you are unsure which subscription best meets your needs, contact your Red Hat account manager for advice. For more details of the Red Hat subscription model, see Subscription Concepts and Workflows.

The following are example Red Hat subscriptions which provide inheritable subscriptions:

This guide uses a Red Hat Enterprise Linux for Virtual Datacenters (VDC) subscription in all examples. The workflow for all inheritable subscriptions is identical.

Confirming if virt-who is Required

To confirm if the virt-who daemon is required, either use the Red Hat Certificate Tool, or contact Red Hat Support. The command line Red Hat Certificate Tool (rct) reads a Subscription Manifest file and displays details of the manifest in plain text. The Red Hat Certificate Tool is available in subscription-manager-1.17.10 (or later) package, in either Red Hat Enterprise Linux 7.3 or Fedora 24.

The virt-who daemon is required if the rct output includes Virt Limit: unlimited, Requires Virt-who: True, or both. In this example, both are included, confirming that the virt-who daemon is required.

A Virtual Data Center (VDC) subscription is one type of host-based subscription offered by Red Hat. Host-based subscriptions are applied to a host and inherited by its guests. Host-based subscriptions consist of two parts, a pool attached to the virtualization manager or hypervisor, and a pool from which virtual guests inherit their subscription. It is important to note that the virtualization manager or hypervisor’s subscription does not provide entitlement to product content.

To successfully provision virtual machines, and ensure they inherit host subscriptions, you must do the following:

When a virtual machine is first registered, Satellite does not know with which virtualization manager or hypervisor the virtual machine is associated and so cannot assign a subscription. In this case a temporary subscription is granted, valid for a maximum period of 24 hours.

When the virt-who daemon next runs and identifies the virtual machine’s host, a permanent subscription is applied, provided the host has available subscriptions of the right type. If a permanent subscription is granted, the virtual machine’s subscription status is changed to Subscribed.

A virtual machine that has been granted a temporary subscription might, after the 24-hour period, automatically select a subscription intended for a physical host and so restrict the number of subscriptions available. When the 24-hour period expires, the host’s status is changed to Not subscribed if it has been unable to request a suitable subscription.

When a virtual machine is granted a temporary subscription, you have several options available:

This situation should be avoided as it results in more subscriptions being consumed than would otherwise be consumed. A virtual machine assigned a temporary subscription might be assigned subscriptions intended for physical hosts. For example, a virtual machine with 2 CPUs might be granted two subscriptions instead of a single VDC subscription.

The process of registering a virtual machine is as follows:

A registered host, virtual or physical, has a subscription status based on its installed Products and attached subscriptions.

To verify the status of a virtual machine’s subscription in the Satellite web UI:

Subscription Status Meanings