WebSphere Extended Deployment, Version 6.0.x
             Operating Systems: AIX, HP-UX, Linux, Solaris, Windows, z/OS


Troubleshoot application placement

Occasionally, you might encounter application placement behavior that is not expected. This topic describes some common things to look for when application placement is not working, or not working the way that you expect.

Application placement changes are not occurring when you expect

Depending on your administrative role, you are allowed specific privileges when configuring the autonomic managers. The following list shows the administrative roles and privileges for configuring the autonomic managers:

Monitor
Can view the information.
Operator
Can view the information on the configuration tab.
Can change the settings on the runtime tab.
Configurator
Can change the configuration but not the runtime settings.
Administrator
Has all privileges.
If you find your application placement changes are occurring in an unexpected fashion, use the following course of action:
  1. Verify that the placement controller is enabled. In the administrative console, click Operational policies > Autonomic Managers > Application placement controller. Verify that the placement controller is enabled.
  2. Verify that the subject cluster or clusters are dynamic clusters. The application placement controller acts upon dynamic clusters only. In the administrative console, click Servers > Dynamic clusters. Check that the Operational Mode field for each of the subject clusters is Automatic. If not, select the dynamic clusters and click Automatic. After you select automatic for your dynamic clusters, click Set Mode.
  3. Verify that the configured minimum time between placement change parameters is not set too high. In the administrative console, click Operational policies > Autonomic Managers > Application placement controller. Set the value in the Minimum time between placement changes field to a suitable value. Acceptable values range from 1 minute to 24 hours.
  4. Verify that the configured application placement controller cycle is not too long. To modify that setting from the administrative console, click Operational policies > Autonomic controllers > Application placement controller > Custom properties. Add a custom property, by clicking New. In the Name field, enter minControlCycleLength and in the Value field, provide a suitable time value in minutes, such as 1.

If the problem still persists after making these suggested changes and restarting the cell, verify the following problems.

Dynamic cluster members are not inheriting properties from the template

You must save dynamic clusters to the master repository before making changes to the server template. If you have dynamic cluster members that do not inherit the properties from the template, the server template probably incurred changes in an unsaved workspace. To fix this issue, delete the dynamic cluster, then recreate it.

Save your changes to the master repository. You can ensure that your changes are saved to the master repository after clicking Finish, by clicking Save in the message window in the top frame. Click Save again in the Save to Master Configuration window. Click Synchronize changes with nodes.

Not enough active servers in a dynamic cluster

If you encounter problems where not enough servers are running in the dynamic cluster, try the following actions:
  • When the nodes in the node group are not highly utilized, verify the service policy is met. At times the policy might not be defined clearly and although the system is able to meet them, although not to your expectations. To check or change a service policy in the administrative console click Operational policies > Service policies > Select an existing policy. Check the goal type, goal value, and importance of the policy, and make any necessary changes.
  • When the nodes in the node group are highly utilized, compare the service policy goals of this cluster to service policy goals of other active clusters. If the traffic that belongs to this cluster has lower importance or looser target service goals relative to the other clusters, it is more likely that the system instantiates fewer servers for this cluster. To check or change a service policy in the administrative console, click Operational policies > Service policies > Select an existing policy.
  • When the node group seems to have some extra capacity, but your service policies are not met, check the configuration settings on the dynamic cluster. There might be too few instances of the dynamic cluster created as a result of the maxInstances policy setting.



Related tasks
Configuring dynamic application placement
Related reference
Administrative roles and privileges
Reference topic    

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Last updated: Nov 30, 2007 3:59:37 PM EST
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