Finding different configurations of the same component in Engineering Workflow Management SCM and RMM contributions (Detecting deep component skew)

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In a global configuration, contributions from IBM Engineering Workflow Management source control management (SCM) and IBM Engineering Systems Design Rhapsody - Model Manager , often contain nested local configurations. When a configuration hierarchy contains different configurations of the same component, skew occurs. To detect skew in nested local configurations, install the Eclipse Amlen MQTT broker and set values for the MQTT advanced server properties.

Before you begin

  • You must be assigned the Administrator role in the Global Configuration Management (GCM) application.
  • All applications must be at the current version.
  • Message Queuing Telemetry Transport (MQTT) broker: Your deployment must include an MQTT broker. Ensure that the broker is running and available. Only Eclipse Amlen is supported, which is available only for Linux servers.

    If you already have Eclipse Amlen installed to support Engineering Workflow Management clustering, you can use the same Eclipse Amlen instance, or install another instance on a different host to prevent a single point of failure.

    Eclipse Amlen is not part of the Engineering Lifecycle Management installation. You must obtain and install it separately. For more information, see the related link to the interactive installation guide. When you answer the questions in the guide, in the Supporting applications section, select Global Configuration Management, and click Yes for at least one of the questions in that section. In the generated instructions, click the link to the section about installing Eclipse Amlen.

About this task

Component skew occurs when a configuration hierarchy contains different configurations of the same component. A configuration lead must decide whether skew is intentional.

To detect component skew in contributions from these applications, you must configure Eclipse Amlen.

Example

The following image shows an example of component skew in contributions from Engineering Workflow Management SCM.
  • The Car stream contains component skew due to different streams of the camera component.
  • The Camera global streams contain different Engineering Workflow Management snapshots.
Image showing component skew in an Engineering Workflow Management SCM contribution in a configuration hierarchy
In this scenario, the configuration lead might decide that the skew is not intentional, and repair skew in one of the following ways:
  • In one of the Camera global configurations, replace the Camera Engineering Workflow Management snapshot with the correct Engineering Workflow Management snapshot.
  • In the Parking Assist Initial Development or Adaptive Cruise Control Initial Development configurations, replace the Camera global configuration with the correct Camera global configuration.
Note: In this example, component skew in the Engineering Workflow Management snapshots would have also been detected in the GCM application version 6.0.5, but only for the Camera - Model X configurations. Starting in application version 6.0.6, the component skew report also indicates that the Engineering Workflow Management Web UI, Java UI, and Prerequisites baselines are in component skew.

If you don't complete the following steps, you can see the nested configurations from these applications in the tree, but skew in their nested local configurations is not detected.

Procedure

  1. Set the following properties on the Advanced Properties page at https://server_name:port/gc/admin:
    1. MQTT broker URI: Example: tcp://broker_server_name:1883

      The broker URI must use a fully qualified domain name (FQDN) so that it resolves to the same MQTT broker across all the participating servers.

      Port 1883 is typically the default port for the MQTT protocol.

      Note: If you rename the host or move the MQTT broker to a different host, you must manually set the MQTT broker URI property on the Advanced Properties page.
    2. Use MQTT for contribution cache: Set this option to true.
  2. Stop and restart the GCM application.
  3. Stop and restart the applications use this GCM application, such as all IBM Engineering Lifecycle Management applications that are part of the same deployment, or other Engineering Lifecycle Management applications where you can set a global configuration context.
    Note: If you install other applications that contribute to global configurations and either of the following GCM properties is not set to its default value, you must restart those new applications after you register them:
    • MQTT broker URI
    • Use MQTT for contribution cache

Results

When skew occurs in contributions from Engineering Workflow Management SCM or RMM, a message is shown in the configuration hierarchy.

Configuration leads can also run a component skew report to discover which configurations belong to the same component. Then, they can decide which configurations to update to more recent streams or baselines. For more information about how configuration leads check for skew, see Detecting component skew (checking for different configurations of a component).