Handling probe errors

If a probe has been set to run in a test but IBM® DevOps Test Performance Test Server (Test Performance Test Server) is unable to run it, the following error will be displayed in the test console:


Probe definition does not have a Hosting Agent.

Usually, this error is caused when both the following conditions occur:

Systat probe has been selected to monitor an infrastructure component (for example, a messaging server).
An agent for the host has not been configured in the Physical View and has not been included it in the Engines tab of the performance test.

When adding probes to performance tests, users can select parts of the system to be monitored within their environment. The list of available system components to monitor comes from dependencies expressed in Architecture School (for example, a service that depends upon a database). The configuration of these probes in the Physical View must be carried out in the appropriate place.

For example, a database server host might be configured to look at system properties, or an EMS broker configuration might be configured to monitor its own statistical data. In both cases, each probe configuration requires a hosting agent (that is, the agent that will execute the probe).

Most probes can be executed on any agent, even if they are not installed on the system under test, because they use remote APIs to capture statistics. However, the Systat probe needs to be installed on the system under test. Therefore, the hosting agent must be configured as that host where the probe is installed.

A similar configuration scenario is shown in the following example:

Operations depend on the MQ server in the Architecture School Logical View.

In the Physical View, an agent has been configured on the local testing server, ghc-pc2. The MQ server is on server gh-pc1.

A performance test allows probes to be configured for the MQ server.

If the performance test is executed using the agent on ghc-pc2, the following hosting agent error message will be displayed:
```
[Error] Error executing test: Probe definition does not have a Hosting agent defined: plug-in.custom.SysStat
```
The error occurs because the agent on ghc-pc2 cannot run the Systat probe for the MQ server because it is not running in the same location.
To resolve this error, an agent must be added for the MQ server host and included in the performance test.
The next time that the test is executed, successful communication with the probe can be viewed in the test console.
```
Initialised probes on: http://gh-pc1:4476
Communicating with Probe on http://gh-pc1:4476 via http://gh-pc1:59444
```