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.
Administrative roles
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.
Application placement changes are not occurring when
you expect
If you find your application placement changes
are occurring in an unexpected fashion, use the following course of
action:
- 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.
- 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.
- 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.
- 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.