You specify the behavior of the Auto Deploy server by using a set of rules written in PowerCLI. The Auto Deploy rules engine checks the rule set for matching host patterns to decide which items (image profile, host profile, or vCenter Server location) to provision each host with.
The rules engine maps software and configuration settings to hosts based on the attributes of the host. For example, you can deploy image profiles or host profiles to two clusters of hosts by writing two rules, each matching on the network address of one cluster.
For hosts that have not yet been added to a vCenter Server system, the Auto Deploy server checks with the rules engine before serving image profiles, host profiles, and inventory location information to hosts. For hosts that are managed by a vCenter Server system, the image profile, host profile, and inventory location that vCenter Server has stored in the host object is used. If you make changes to rules, you can use Auto Deploy PowerCLI cmdlets to test and repair rule compliance. When you repair rule compliance for a host, that host's image profile and host profile assignments are updated.
The rules engine includes rules and rule sets.
Rules can assign image profiles and host profiles to a set of hosts, or specify the location (folder or cluster) of a host on the target vCenter Server system. A rule can identify target hosts by boot MAC address, SMBIOS information, BIOS UUID, Vendor, Model, or fixed DHCP IP address. In most cases, rules apply to multiple hosts. You create rules by using Auto Deploy PowerCLI cmdlets. After you create a rule, you must add it to a rule set. Only two rule sets, the active rule set and the working rule set, are supported. A rule can belong to both sets, the default, or only to the working rule set. After you add a rule to a rule set, you can no longer change the rule. Instead, you copy the rule and replace items or patterns in the copy.
Active Rule Set
When a newly started host contacts the Auto Deploy server with a request for an image profile, the Auto Deploy server checks the active rule set for matching rules. The image profile, host profile, and vCenter Server inventory location that are mapped by matching rules are then used to boot the host. If more than one item of the same type is mapped by the rules, the Auto Deploy server uses the item that is first in the rule set.
Working Rule Set
The working rule set allows you to test changes to rules before making the changes active. For example, you can use Auto Deploy PowerCLI cmdlets for testing compliance with the working rule set. The test verifies that hosts managed by a vCenter Server system are following the rules in the working rule set. By default, cmdlets add the rule to the working rule set and activate the rules. Use the NoActivate parameter to add a rule only to the working rule set.
You use the following workflow with rules and rule sets.
Make changes to the working rule set.
Use cmdlets that execute the working rule set rules against a host to make sure that everything is working correctly.
Refine and retest the rules in the working rule set.
Activate the rules in the working rule set.
If you add a rule and do not specify the NoActivate parameter, all rules that are currently in the working rule set are activated. You cannot activate individual rules.
See the PowerCLI command-line help and Managing Auto Deploy with PowerCLI Cmdlets.