7.4

Table Of Contents
The allocation model for a reservation depends on the allocation model in the associated datacenter.
Available allocation models are Allocation Pool, Pay As You Go, and reservation pool. For information
about allocation models, see thevCloud Director or vCloud Air documentation.
In addition to defining the share of fabric resources allocated to the business group, a reservation can
define policies, priorities, and quotas that determine machine placement.
To provision successfully, the reservation must have sufficient available storage. The reservation's
storage availability depends on:
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How much storage is available on the datastore/cluster.
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How much of that storage is reserved for that datastore/cluster.
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How much of that storage is already allocated in vRealize Automation
For example, even if the vCenter Server has storage available for the datastore/cluster, if sufficient
storage is not reserved in the reservation then provisioning fails with a "No reservation is available to
allocate..." error. The allocated storage on a reservation depends on the number of VMs (regardless of
their state) on that specific reservation. See the VMware Knowledge Base article Machine XXX: No
reservation is available to allocate within the group XXX. Total XX GB of storage was requested
(2151030) at http://kb.vmware.com/kb/2151030 for more information.
Understanding Selection Logic for Cloud Reservations
When a member of a business group creates a provisioning request for a cloud machine,
vRealize Automation selects a machine from one of the reservations that are available to that business
group. Cloud reservations include Amazon, OpenStack, vCloud Air, and vCloud Director.
The reservation for which a machine is provisioned must satisfy the following criteria:
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The reservation must be of the same platform type as the blueprint from which the machine was
requested.
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The reservation must be enabled.
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The reservation must have capacity remaining in its machine quota or have an unlimited quota.
The allocated machine quota includes only machines that are powered on. For example, if a
reservation has a quota of 50, and 40 machines have been provisioned but only 20 of them are
powered on, the reservation’s quota is 40 percent allocated, not 80 percent.
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The reservation must have the security groups specified in the machine request.
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The reservation must be associated with a region that has the machine image specified in the
blueprint.
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The reservation must have sufficient unallocated memory and storage resources to provision the
machine.
In a Pay As You Go reservation, resources can be unlimited.
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For Amazon machines, the request specifies an availability zone and whether the machine is to be
provisioned a subnet in a Virtual Private Cloud (VPC) or a in a non-VPC location. The reservation
must match the network type (VPC or non-VPC).
Configuring vRealize Automation
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