Policies

A service policy reflects the behavior of a set of resources that logically impacts a service. The policy specifies which resource attribute is monitored and how those attributes are interpreted to determine the health of a service. A number of common policies are available out-of-the-box, and users can create their own policies to more accurately monitor service resources.
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A service policy reflects the behavior of a set of resources that logically impacts a service. The policy specifies which resource attribute is monitored and how those attributes are interpreted to determine the health of a service. A number of common policies are available out-of-the-box, and users can create their own policies to more accurately monitor service resources.
A policy includes the following basic components:
  • Attribute map
    The attribute map serves two purposes. First, it specifies which resource attribute is monitored. Second, it maps resource attribute values to a set of resource health values. The mapping is done based on the logical severity of the attribute value. For example, if the attribute map represents the Port Status attribute, a disabled port can be logically considered as a down resource. If the attribute map represents the status of a response time test, a minor threshold violation and a slightly degraded resource can be considered.
    This mapping allows policy rule sets to handle various resource types in a common way by having only to consider the resource health values of down, degraded, and slightly degraded.
  • Rule set
    A rule set consists of a number of statements evaluating the cumulative mapped resource health values of a set of service resources against some criteria. Each rule within the set specifies the criteria and the resulting service health value if the criteria are met. For example, a rule can look something like: When all resources are down the service is down. This means that given the mapping of the monitored attribute if all resources have a resource health of down the resulting health of a service using this policy can be down.
    As mentioned, the rule set consists of multiple statements or rules. The rules are evaluated from the top down, and the first rule which is satisfied determines the health of any service using that policy. If none of the rules in the rule set are satisfied, the service health can be up.
 Editing and deleting policies and attribute maps and rule sets can be performed by authorized personnel who are aware of the potential ramifications of these actions, particularly policies for services that are watched by Service Level Agreements (SLAs).