Policy precedence best practices
Policy precedence is the priority of a policy and ranges from 0 to 999. A lower number indicates a higher priority. Policy precedence controls the configuration applied to the PATROL Agents and Infrastructure Management servers when there are conflicting or overlapping configurations defined between two or more policies.
The following sections in this topic describe how precedence is applied and best practices regarding usage of precedence values.
Policy precedence behavior
- Policies are applied on PATROL Agents based on the Agent Selection Criteria that is defined during policy creation.
- If two policies attempt to manage the same variable, such as /AgentSetup/historyRetentionPeriod, the PATROL Agent resolves the conflict by evaluating the precedence of the involved policies. Consider the following examples:
Example: with conflict | Example: without conflict | |
|---|---|---|
| Scenario details | Policy A: Precedence number - 099 Includes configuration for the amount of history the Agent should retain. /AgentSetup/historyRetentionPeriod - 7 (retention in days) | Policy A: Precedence number - 699 Includes configuration for monitoring the following Microsoft Windows services:
|
Policy B: Precedence number - 070 Includes configuration for the amount of history the Agent should retain. /AgentSetup/historyRetentionPeriod - 1 (retention in days) | Policy B: Precedence number - 499 Includes configuration for monitoring the following Microsoft Windows services:
| |
| When policies A and B are applied to a PATROL Agent | The Agent resolves the conflict that is related to the /AgentSetup/historyRetentionPeriod variable by evaluating the precedence values of the policies. Because the precedence value of Policy B (070) is lower than that of Policy A (099), the variable value of Policy B, that is 1, is applied to the Agent. Remember the rule: Lower the number, higher the precedence. | The Agent is configured according to the union of policy A and policy B because there are no conflicts. All the Windows services configured in policy A and policy B are monitored. |
Important: Do not use the same precedence value
BMC recommends that you do not use the same precedence values for different policies. In such a scenario, the policies behave in the following way:
- If polices with the same precedence value have the same KM parameters with different threshold settings, and they apply to different platforms, the policy with the latest time stamp is applied.
- If policies with the same precedence value have different KM parameters, and they apply to the same host, both policies are applied.
Policy naming guidelines
To easily track the configurations that are applied to PATROL Agents and to know the order in which the precedence is being applied, you must keep the policies organized.
BMC recommends that you organize policies according to the precedence numbers when creating and editing policies.
Consider the following options as examples for organizing policies:
1) Use policy precedence number in policy name To enable easy sorting of policies, include the precedence number of a policy as a prefix in the policy naming, as per the following format: <precedence number>_<policyname>. For example:
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2) Use policy sorting information in policy name To enable easy searching of policies, include policy-specific information in the policy naming. For example, you can easily you can easily find all Windows policies if the policies are named as follows.
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Policy precedence values
BMC recommends that you define a precedence numbering system. Related policies can then be grouped according to the numeric ranges of the precedence numbers. Consider the following chart as an example.
Assign precedence numbers starting with the highest number in the range and then continue assignment in the descending order. By doing so, you can leave the lower numbers in the range for specific use cases.
Precedence range | Applicable for | Additional information |
|---|---|---|
001 – 049 | Temporary policy overrides | Use for a short term for specific policies until a complete policy is developed. |
050 – 099 | Policies for low-level behavior management in Agents | Use for policies that you always want to enforce. For example, Agent tuning, event propagation. |
100 – 299 | Polices that are specific to a logical group of servers | Use for policies such as vCenter monitoring, Exchange Servers, Oracle Servers, Location Related Servers or Services, Agent tuning overrides, and so on. |
300 – 499 | Specific platform variance policies | Use for policies such as Remote OS monitoring, Windows 2008 monitoring, Linux 6.7 monitoring, Specific Windows services, Specific UNIX processes, and so on. |
500 – 699 | Standard platform policies | Apply as a standard to large groups of Agents. For example, All Windows, all Linux, and so on. |
700 – 899 | Other platform policies | Use for examples such as Storage, Network, SNMP, PING, AWS, Azure, and so on. |
950 – 999 | Prepackaged policies | Reserved for the BMC prepackaged policies. You get these policies when you import the Infrastructure Management PATROL repository. |
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