Why are there blocked hosts for my application?

IBM Spectrum Symphony grid

Verify that hosts are blocked by looking at the Blocked Hosts column in the SOA Workload table on the cluster management console Dashboard. This value indicates the number of hosts that are blocked for your application.

You can find out why a host was blocked for your application in a few different ways:
  • If you are trapping SNMP events, you can check for events regarding blocked hosts.
  • You can inspect the SSM log for your application and look for ERROR messages regarding blocked hosts. To retrieve the SSM log for your application, navigate to System Logs and select ssm.log. Specify the host where your SSM is running and click Retrieve Log List. After the cluster management console returns a log list, view the SSM log for your application.
To unblock hosts for your application:
  1. Navigate to Symphony Workload > Monitor Workload in the cluster management console.
  2. Click on your application name.
  3. Click Blocked Hosts.
  4. To unblock all hosts, select Global Actions > Remove All Hosts from Blocked Hosts. To unblock specific hosts, select Global Actions > Remove Hosts from Blocked Hosts for each host.

IBM Spectrum Symphony Developer Edition

IBM® Spectrum Symphony Developer Edition can block slots from your application. If a slot is blocked for your application, IBM Spectrum Symphony Developer Edition cannot allocate that slot back to your application. You will have no resources or fewer resources than expected serving your application, more tasks will be in the PENDING state, and workload will complete at a slower rate.

To check for blocked slots and unblock slots for your application:

  1. Navigate to $SOAM_HOME/logs on Linux® or %SOAM_HOME%\logs on Windows.
  2. Open the ssm.hostname.appname.log file and search for WARN or ERROR messages regarding blocked hosts. If you find such a message, one or more slots may be blocked.
  3. To unblock the slots:
    1. In the cluster management console, navigate to Symphony Workload > Configure Applications.
    2. Disable your application by selecting Actions > Disable next to your application name.
    3. Enable your application again by selecting Actions > Enable next to your application name.
Tip: You can also restart IBM Spectrum Symphony Developer Edition to unblock slots.