Chapter 1. Introduction

Virtual machines can use host-based subscriptions instead of consuming entitlements from physical subscriptions. A host-based subscription is attached to a hypervisor and entitles it to provide subscriptions to its virtual machines. Many host-based subscriptions provide entitlements for unlimited virtual machines.

To allow virtual machines to inherit subscriptions from their hypervisors, you must install and configure virt-who. Virt-who queries the virtualization platform and reports hypervisor and virtual machine information to Red Hat Satellite.

When a virtual machine is registered with an activation key that has no subscriptions attached and auto-attach set to true, and sufficient host-based subscriptions are available, one of the following behaviors occurs:

If auto-attach is enabled, but virt-who is not running or there are no host-based subscriptions available, Satellite attaches physical subscriptions to the virtual machines instead, which might consume more entitlements than intended.

If auto-attach is not enabled, virtual machines cannot use host-based subscriptions.

To see if a subscription requires virt-who, in the Satellite web UI, navigate to Content > Subscriptions. If there is a tick in the Requires Virt-Who column, you must configure virt-who to use that subscription.

Satellite provisions a virtual machine.

The virtual machine requests a subscription from Satellite Server.

Satellite Server grants the virtual machine a temporary subscription, valid for a maximum of seven days, while it determines which hypervisor the virtual machine belongs to.

Virt-who connects to the hypervisor or virtualization manager and requests information about its virtual machines.

The hypervisor or virtualization manager returns a list of its virtual machines to virt-who, including each UUID.

Virt-who reports the list of virtual machines and their hypervisors to Satellite Server.

Satellite Server attaches a permanent subscription to the virtual machine, if sufficient entitlements are available.

To allow virtual machines to inherit subscriptions from their hypervisors, complete the following steps:

Virt-who is configured using files that specify details such as the virtualization type and the hypervisor or virtualization manager to query. The supported configuration is different for each virtualization platform.

[virt-who-config-1]
type=libvirt
hypervisor_id=hostname
owner=Default_Organization
env=Library
server=hypervisor1.example.com
username=virt_who_user
encrypted_password=$cr_password
rhsm_hostname=satellite.example.com
rhsm_username=virt_who_reporter_1
rhsm_encrypted_password=$user_password
rhsm_prefix=/rhsm

The type and server values depend on the virtualization platform. The following table provides more detail.

The username refers to a read-only user on the hypervisor or virtualization manager, which you must create before configuring virt-who. The rhsm-username refers to an automatically generated user that only has permissions for virt-who reporting to Satellite Server.