How Intelligent Placement Works
This topic explains how Commander decides where to deploy new service requests. To configure automated deployment, see Configuring Automated Deployment for Approved Service Requests.
Commander first filters out all invalid deployment destinations. Then, if multiple deployment destinations are valid, it rates them.
To be considered valid, a deployment destination must fulfill many criteria. For example, a deployment destination must:
- be assigned to the requester, the requester's group, or the requester's organization
- target the same managed system as the service. For multi-cloud services, the deployment destination must target one of the managed systems in the multi-cloud template.
- have access to required storage and network resources. See also Setting the Storage Tier for a Datastore or Datastore Cluster and Assigning Network Zones.
- provide Intelligent Placement capabilities required by the service. You can configure both required and preferred Intelligent Placement capabilities.
There are also many managed-system-specific criteria, such as:
- vCenter and SCVMM targets must have sufficient capacity without exceeding the configured datastore threshold.
- AWS targets must also be in the same region as the source AMI (unless the AMI is from the Amazon Marketplace). This means that you need to configure a separate deployment destination for each AWS region.
- For Azure, a valid target must fulfill several additional criteria. For example, it must:
- target the same region as the source image. This means that you need to configure a separate deployment destination for each Azure region.
- target a region that offers the required instance type, in the case of custom images
- offer the required storage. This requirement applies only for components requiring unmanaged storage on a particular storage tier, and for custom images with an OS disk in a particular unmanaged storage account.
- have a subnet with the required network zone, if the component requires a particular network zone
- have a subnet with free IP addresses
Storage reserved for in-progress deployment and fulfillment is excluded from available capacity.
The Placement Report provides more information on how deployment destinations are validated.
How Commander rates multiple valid deployment destinations
If Commander has determined that multiple deployment destinations are valid, four criteria are used to rate them:
- Quota: Each destination is rated based on how many of the requested workloads it can accommodate, given the quota available on that destination, when per-destination quota is configured. The destination accommodating the highest number of workloads is given a rating of 100. A destination that can accommodate 0 workloads is given a rating of 0. Destinations that can accommodate any number between 1 and the highest number are given proportional ratings. For example, if the destination that can accommodate the greatest number of workloads can hold 10, a destination that can hold 7 workloads is given a rating of 70.
- Cost: Each destination is rated based on how much this service will cost. The cheapest destination is given a rating of 100. A destination that is at least twice as expensive as the cheapest destination is given a rating of 0. All other destinations in the range are given proportional ratings. For example, if the cheapest destination costs $1000, any destination that costs $2000 or more is rated 0, and a destination that costs $1500 is given a rating of 50.
- Placement attributes: Each destination is rated based on whether it provides the placement capabilities preferred for this service (remember that you can configure both required and preferred Intelligent Placement capabilities). All placement attribute ratings for a particular destination are averaged for a total placement attribute rating.
- Capacity: Each private cloud destination is rated based on how much capacity is available on the target cluster, given the configured default VM workload. The destination accommodating the highest number of workloads is given a rating of 100. A destination that can accommodate 0 workloads is given a rating of 0. Destinations that can accommodate any number between 1 and the highest number are given proportional ratings. For example, if the destination that can accommodate the greatest number of workloads can hold 10, a destination that can hold 7 workloads is given a rating of 70.
By default, quota is rated as the highest priority, cost is the second priority, and placement attributes are the third priority, but you can customize the placement priority. The Capacity rating always has the lowest priority because it's based on the last seven days of performance data.
All four individual ratings are combined into a single destination rating, using a weighted average that considers the customizable placement priority:
- First priority: 2
- Second priority: 1.5
- Third priority: 1.0
- Capacity: 0.5
You can tune the relative weighting of placement priorities as well as how destinations are rated for placement attributes and cost through advanced system properties. See Advanced Configuration through System Properties to learn how to set system properties. To find properties that control Intelligent Placement, search on the Advanced Configuration page in Commander for "placement", as shown in the following image:
We recommend contacting firstname.lastname@example.org before changing system properties.
Lower-priority individual ratings can combine to override a higher-priority rating. For example, assuming the default placement priorities are used, a cheaper destination might be chosen even if it has less available quota than a destination that's expensive and doesn't provide preferred placement attributes.
The overall rating is used to display the star rating for the Destination element on the service form. A rating of 100 translates into a 5-star rating; a rating of 80 translates into a 4-star rating, and so on.
Views Menu > Service Requests
All Access Rights Levels
To find out why Commander chose a particular destination for a requested service, or why no destinations were valid:
- Click Views > Service Requests.
- To view details for a request, select it, and click Request Details.
- Click the Service level in the tree, then click the Placement tab.
All service requests are listed.
Filtered-out Destinations: A list of destinations that were filtered out because:
- they were invalid for this service - for example, destinations that don't provide a required placement attribute
- there's a temporary configuration issue, such as lack of disk space
Rated Destinations: A list of all valid destinations, with an overall rating from 1 to 100. Ratings from 1 to 100 are also provided for cost, quota, preferred placement attributes and capacity. If no destinations were valid for this service, the placement report explains why.
For multi-cloud services, a destination appears under Filtered-out Destinations if it's filtered out for all possible multi-cloud configurations of the service.