Chapter 4. Prerequisites

Before proceeding to install virt-who, ensure the following prerequisites are met.

4.1. Authentication Requirements

Create an account on each virtualization manager, such as VMware vCenter and Red Hat Virtualization Manager, or individual hypervisors so the virt-who agent can retrieve the list of guest virtual machines. Each connection is separate, so you can use different accounts for each connection if required. Each account, generally known as a service account, should be dedicated to this purpose, have read-only access, and have a non-expiring password.

4.2. Software Requirements

The virt-who agent must be installed on a instance of Red Hat Enterprise Linux dedicated to the purpose. The underlying server can be either physical or virtual.

4.3. Subscriptions

Subscriptions are specific to organizations. Although you can configure the virt-who daemon to support multiple organizations, you cannot share subscriptions across organizations.


You must have one virtual data center subscription for each organization and for each hypervisor.

4.4. Preparing the virt-who Host

Before installing the virt-who daemon, a Red Hat Enterprise Linux instance must be installed and configured as follows.

  1. Install Red Hat Enterprise Linux, version 7 (recommended) or 6.

    Only a CLI environment is required. For help with this step, see the Red Hat Enterprise Linux 7 Installation Guide or the Red Hat Enterprise Linux 6 Installation Guide.

  2. Register the Red Hat Enterprise Linux server to the Subscription Management Server:

    # subscription-manager register --username=admin --password=p@sswd \
    --org=organization_label --auto-attach
  3. Open a network port for HTTPS:

    To enable virt-who to communicate with the subscription service, TCP port 443 must be opened.

    On Red Hat Enterprise Linux 7:

    # firewall-cmd --add-port="443/tcp"
    # firewall-cmd --add-port="443/tcp" --permanent

    On Red Hat Enterprise Linux 6:

    # iptables -A INPUT -m state --state NEW -p tcp --dport 443 -j ACCEPT
    # service iptables save

4.5. Installing virt-who

  1. Install the virt-who package.

    # yum install virt-who