Creating a health policy: Define health policy general properties

Use this page to create health policies, which are used to perform a variety of health-based assessments on clusters, dynamic clusters, and application server instances running on nodes.

To view this administrative console page, click Operational policies > Health policies > New.

Privileges for health policies differ, depending on the user’s administrative role. Roles include monitor, operator, configurator, and administrator. If you are a user with either a monitor or an operator role, you can only view health policy information. If you are a user with either a configurator or an administrator role, you have all configuration privileges for health policies.

When you complete all of the required fields, click Next to proceed.

Name

Specifies the name of a health policy. The health policy name is required and must be unique among all the health policies in the cell.

The name cannot begin with a period (.) or a space. A space does not generate an error, but leading and trailing spaces are automatically deleted. Use meaningful and consistent health policy names. For example, age-based health policies can be indicated by naming the policies AGE_20DAYS, AGE_15DAYS, and so on.

Description

Specifies an additional description of the health policy. The description is optional. You can edit the description when you are creating or editing a health policy. Consider using the optional description when you are using many health policies or when multiple administrators manage the same set of health policies.

Predefined health condition

The health condition defines the specific policy that is implemented. Predefined health conditions are those that ship with WebSphere Virtual Enterprise.

Some policies are prevention-based and some are detection-based. Prevention-based policies are used to avoid conditions that might lead to problems, while the detection-based policies are used to identify existing conditions and to achieve resolution. These policies can be used to perform health-based assessments on clusters, dynamic clusters, and application server instances running on nodes. In the case of dynamic clusters, regardless of the health policy that you are using, the minimum number of dynamic cluster instances remains running.

  • The age-based condition policy restarts the associated members when their age reaches a certain user-defined value. This restart cleans out all cached and memory acquired data. If you select age-based condition policy, you must define the age criteria. The age-based condition is supported for all server types.
  • The excessive request timeout condition policy tracks the memory that is used for request timeouts. When the percentage of timeouts exceeds the breach of condition, the members are restarted. If you select the excessive request timeout condition, you must set the memory used percentage threshold. The excessive request timeout condition is supported for all server types.
    Restriction: The excessive request timeout condition does not apply to Java Message Service (JMS) and Internet Inter-ORB Protocol (IIOP) traffic.
  • The excessive response time condition policy tracks the requests and the amount of time they take to complete. Use this policy to clean up servers that have an average number of requests that take longer than a specified time. If an average number of requests takes longer than a certain amount of time, the members are restarted. When you select the excessive response time policy, you must define the response time threshold. The excessive response time condition is supported for all server types.
  • The memory condition: excessive memory usage policy tracks the memory usage for a member. When the memory usage exceeds a percentage of the heap size for a specified time, actions are taken to correct this situation. If you define the health policy against a standalone server, static cluster, or dynamic cluster in manual mode, then the member stops and restarts. If you define the health policy against a dynamic cluster that is in automatic or supervised mode, then the member that is flagged by the condition stops. The placement controller dynamically decides which, if any, servers to start based on its evaluation of the environment. These actions occur automatically if you are in automatic mode. If you are in supervised mode, you can approve the runtime tasks are generated to correct the situation. If you select the excessive memory usage policy, you must define the memory used and the time-over-memory threshold. The excessive memory usage condition is supported only on application servers on nodes that run WebSphere Application Server or WebSphere Application Server Community Edition. You cannot define the excessive memory usage condition for other middleware server types.
  • The memory condition: memory leak policy tracks consistent downward trends in free memory that is available to a server in the Java heap. The detection level setting determines when these trends are detected. If you select the memory condition: memory leak policy, you must define a detection level. The slower detection level setting requires the most historical data. The normal and faster detection level settings require the same amount of historical data, but the faster setting allows analysis before the Java heap has expanded to its maximum configured size. This provides earlier detection capability, but is also more prone to false positives. This condition supports heap dumps in addition to server restarts as reactions. The memory leak condition is not supported for other middleware server types.
  • The storm drain condition policy tracks stuck requests. The server that is associated with this policy restarts when the specified detection level is reached. Storm drain detection relies on change point detection on a given time series data. The metrics that are used for detecting storm drain are the response times and deployment workload manager weights that are observed for the server. The storm drain condition applies only to dynamic clusters and cells. If you select the storm drain condition policy, you must select the detection level.

    To detect change points, the health controller calculates a left mean and a right mean for a given point. For a point, the left mean consists of the mean value of N samples that arrive prior to this sample, and the right mean is the mean value of N samples, including the current point, that arrive later. The difference of the left and the right mean values is stored and compared with other differences in a set of values to N to determine if this difference is a local maxima. If this difference is the maximum difference, then the point to which this difference corresponds, is declared as a change point. The two metrics that are used for detecting storm drain are the response times and dynamic workload manager weights that are observed for the server.

    The storm drain condition is supported for all server types.
    Restriction: The storm drain condition does not apply to JMS and IIOP traffic.
  • The workload condition policy restarts the members when a certain user-defined number of requests are serviced. This policy cleans out the memory and caches. If you select the workload policy, you must define the total request criteria. The workload condition is supported for all server types.
Custom health condition

You can define health conditions if the existing health conditions do not fit your needs. Custom health conditions can be tested against metrics in your environment.




WebSphere Virtual Enterprise information center (online)

Related information
Health policy collection
Health policy settings
Creating a health policy: Define health condition properties
Creating a health policy: Specify members to monitor
Custom actions collection
Custom actions settings

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