Monitor and tuning health management

Operating Systems: AIX, HP-UX, Linux, Solaris, Windows, z/OS

Monitor and tuning health management

Health management comes equipped with smart defaults that accommodate most environments. However, if you discover that your health controller is not working the way you want, then tune the default parameters.

Before you begin
Verify that you have proper security authorization in the console to modify these settings. Privileges for health policies differ, depending on the administrative role of the user. 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.

About this task
Use the following steps to modify the health controller parameters. Tune these parameters when the health management infrastructure is not working the way that you want.

Procedure

Access the health controller settings in the administrative console by clicking Operational policies > Autonomic managers > Health controller.
Determine whether you want your changes to be persistent or applied to the current runtime for testing purposes. This page is divided into two tabs: Configuration and Runtime. With the Configuration tab, you can look at fields that are previously configured, and in some cases, make edits to those fields. With the Runtime tab, you can view the fields that are currently used by the health controller, and in some cases, make changes to these values. In contrast to the Configuration tab, these changed values are sent directly to the health controller to change the parameters that the controller uses. These changes are not stored into the repository by default, allowing the user to make a temporary change to the parameters that are not persisted. Tip: Apply your changes to the Runtime tab and test the changes before committing them. You can select Save to configuration in the Runtime tab, so you can make configuration changes and test them in the runtime. After you are sure to commit those changes permanently, click Save to configuration.
Modify and test your settings.

Control Cycle Length Specifies the time between consecutive health checks. The value is specified in minutes and ranges from 1 to 60 minutes. Longer control cycles reduce the health monitoring load. The disadvantage is that health conditions that occur during that period are not detected until the next control cycle. For example, if you have a health policy with a workload condition of 10,000 requests associated to an application server and the value is specified as 60 minutes, the health controller checks every 60 minutes to determine if the application server has served 10,000 requests. If it has serves 9,999 requests when it checks, it checks again for another 60 minutes (the control cycle length), so the server can actually serve more than 10,000 requests prior to a restart.
Maximum Consecutive Restarts Number of attempts to revive an application server after a restart decision is made. If this number is exceeded, the assumption is that the operation failed and restarts are disabled for the server. The value must be a whole number between 1 and 5, inclusive.
Minimum Restart Interval Controls the minimum amount of time that must elapse between consecutive restarts of an application server instance. If a health condition for an application server is breached during that time, the restart is set to a pending state. When the minimum restart interval passes, the restart occurs. The value can range from 15 minutes to 365 days, inclusive. A value of 0 disables the minimum restart value.
Restart Timeout Consists of the sequence of stop and start server actions. The restart timeout specifies how long to wait for a server to stop before explicitly checking its state and attempting startup. If the length of time to start and stop an application server is unusually high, you might want to set this value accordingly, so that the restart action does not time out. Always specify the value in minutes. The value can range from 1 minute to 60 minutes, specified as a whole number.
Enable Health Monitoring Enables or disables the operation of the health controller. When enabled, the health controller continuously monitors the health policies in the system. You can disable the health controller without removing the health policies from the system.
Prohibited Restart Times Specifies the times and days of the week during which a restart of an application server instance is prohibited. Specify the start and end times by selecting the hour and minute using a 24 hour clock and by selecting the days of the week.
You can specify multiple time blocks, if needed. If you specify a start time and end time, also specify at least one day of the week that these times are prohibited. The block between the start time and end time cannot cross the midnight boundary. If we need to specify a block of, for example, 10:00 PM to 1:00 AM, specify two blocks, one from 22:00 to 23:59 and one from 00:00 to 01:00. Click Add to add additional time constraints.
You can remove an existing constraint by selecting the check box next to the constraint and by clicking the Remove. As with the minimum restart interval, a restart for a health condition that is violated is delayed until after a prohibited time interval passes.

Results
You have modified the health management configuration settings to tune your system.

What to do next
See Troubleshooting health management for more information about modifying the health management settings when they are not working the way that you want.

Related tasks

Configure health management

Related reference

checkHmmLocation.jacl
Administrative roles and privileges

Control Cycle Length	Specifies the time between consecutive health checks. The value is specified in minutes and ranges from 1 to 60 minutes. Longer control cycles reduce the health monitoring load. The disadvantage is that health conditions that occur during that period are not detected until the next control cycle. For example, if you have a health policy with a workload condition of 10,000 requests associated to an application server and the value is specified as 60 minutes, the health controller checks every 60 minutes to determine if the application server has served 10,000 requests. If it has serves 9,999 requests when it checks, it checks again for another 60 minutes (the control cycle length), so the server can actually serve more than 10,000 requests prior to a restart.
Maximum Consecutive Restarts	Number of attempts to revive an application server after a restart decision is made. If this number is exceeded, the assumption is that the operation failed and restarts are disabled for the server. The value must be a whole number between 1 and 5, inclusive.
Minimum Restart Interval	Controls the minimum amount of time that must elapse between consecutive restarts of an application server instance. If a health condition for an application server is breached during that time, the restart is set to a pending state. When the minimum restart interval passes, the restart occurs. The value can range from 15 minutes to 365 days, inclusive. A value of 0 disables the minimum restart value.
Restart Timeout	Consists of the sequence of stop and start server actions. The restart timeout specifies how long to wait for a server to stop before explicitly checking its state and attempting startup. If the length of time to start and stop an application server is unusually high, you might want to set this value accordingly, so that the restart action does not time out. Always specify the value in minutes. The value can range from 1 minute to 60 minutes, specified as a whole number.
Enable Health Monitoring	Enables or disables the operation of the health controller. When enabled, the health controller continuously monitors the health policies in the system. You can disable the health controller without removing the health policies from the system.
Prohibited Restart Times	Specifies the times and days of the week during which a restart of an application server instance is prohibited. Specify the start and end times by selecting the hour and minute using a 24 hour clock and by selecting the days of the week. You can specify multiple time blocks, if needed. If you specify a start time and end time, also specify at least one day of the week that these times are prohibited. The block between the start time and end time cannot cross the midnight boundary. If we need to specify a block of, for example, 10:00 PM to 1:00 AM, specify two blocks, one from 22:00 to 23:59 and one from 00:00 to 01:00. Click Add to add additional time constraints. You can remove an existing constraint by selecting the check box next to the constraint and by clicking the Remove. As with the minimum restart interval, a restart for a health condition that is violated is delayed until after a prohibited time interval passes.