Governance Engine Hosting Servers

An Engine Host is an OMAG Server that hosts one or more governance engines. Governance engines provide collections of services used to support the governance of the digital landscape and the metadata that describes it. The services within the governance engines may access third party technology to perform their responsibilities or implement their behavior directly.

The engine host uses a metadata server to store the definitions of the governance engines and the services within them. These definitions are retrieved through the Governance Engine OMAS. The Governance Engine OMAS also manages the definition of governance action processes that choreograph calls to the services in a governance engine in order to implement technical controls in the governance program.

Figure 1

Figure 1: Engine Host in OMAG server ecosystem

Typically an engine host is deployed close to where the artifacts/resources/data are stored because it can generate a lot of network traffic when its services are running.

The metadata interfaces needed by the governance engines are provided by the Open Metadata Engine Services (OMES) (or engine services for short). The engine services also run in the Engine Host OMAG Server.

The engine services are:

An engine service is paired with a specific access service running in either a metadata access point or a metadata server. The specific access services are:

The name and URL root of the server where the access service is running is needed to configure an engine service.

The metadata server used by the engine services does not need to be the same metadata server as the one used by the engine host server. This enables the management of metadata about the assets to be maintained close to the assets, and the definitions of the governance engines, services and processes to be maintained close to the governance team. This separation is shown in Figure 2.

Figure 2

Figure 2: Distribution of metadata managed by the engine host

The engine host services have an REST API to query the status of the governance engines running in the engine services. The engine services also have a REST API to query specific details of their governance engines. All of these REST APIs may be called by a view server as part of the support for a user interface.

Configuring the Engine Host Server

Each type of OMAG Server is configured by creating a configuration document. The contents of the configuration document identify the type of server and the options on the services it runs.

Figure 3 shows the structure of the configuration document for an engine host.

Figure 3

Figure 3: Configuration Document for an Engine Host

The tasks for configuring an engine host are as follows.

Below is an example of the configuration for a minimal engine host server. It has a single engine service (Asset Analysis OMES) and the default audit log. Both the Governance Engine OMAS used by the engine host services and the Discovery Engine OMAS used by the Asset Analysis OMES are running on the metadata server called myMetadataServer.

    "class": "OMAGServerConfigResponse",
    "relatedHTTPCode": 200,
    "omagserverConfig": {
        "class": "OMAGServerConfig",
        "versionId": "V2.0",
        "localServerId": "8b745d03-5ffc-4978-81ab-bd3d5156eebe",
        "localServerName": "myserver",
        "localServerType": "Open Metadata and Governance Server",
        "localServerURL": "https://localhost:9443",
        "localServerUserId": "OMAGServer",
        "maxPageSize": 1000,
        "engineHostServicesConfig": {
            "omagserverPlatformRootURL": "https://localhost:9443",
            "omagserverName": "myMetadataServer",
            "engineServices": [
                    "class": "EngineServiceConfig",
                    "engineId": 6000,
                    "engineQualifiedName": "Asset Analysis",
                    "engineServiceFullName": "Asset Analysis OMES",
                    "engineServiceURLMarker": "asset-analysis",
                    "engineServiceDescription": "Analyses the content of an asset's real world counterpart, generates annotations in an open discovery report that is attached to the asset in the open metadata repositories .",
                    "engineServiceWiki": "",
                    "engines" : [ {"engineId" : "daff1dca-984b-4b8a-8a8f-febaf72b82a8",
                                   "engineName" : "engine1", 
                                   "engineUserId" : "engine1UserId"},
                                  {"engineId" : "a80aa0f8-2ea0-4f84-b613-d68becba2693",
                                   "engineName" : "engine2", 
                                   "engineUserId" : "engine2UserId"} ],
                    "engineServiceOperationalStatus": "ENABLED",
                    "engineServiceAdminClass": "org.odpi.openmetadata.engineservices.assetanalysis.admin.AssetAnalysisAdmin",
                    "omagserverPlatformRootURL": "https://localhost:9443",
                    "omagserverName": "myMetadataServer"
        "repositoryServicesConfig": {
            "class": "RepositoryServicesConfig",
            "auditLogConnections": [
                    "class": "Connection",
                    "headerVersion": 0,
                    "displayName": "Console",
                    "connectorType": {
                        "class": "ConnectorType",
                        "headerVersion": 0,
                        "type": {
                            "class": "ElementType",
                            "headerVersion": 0,
                            "elementOrigin": "LOCAL_COHORT",
                            "elementVersion": 0,
                            "elementTypeId": "954421eb-33a6-462d-a8ca-b5709a1bd0d4",
                            "elementTypeName": "ConnectorType",
                            "elementTypeVersion": 1,
                            "elementTypeDescription": "A set of properties describing a type of connector."
                        "guid": "4afac741-3dcc-4c60-a4ca-a6dede994e3f",
                        "qualifiedName": "Console Audit Log Store Connector",
                        "displayName": "Console Audit Log Store Connector",
                        "description": "Connector supports logging of audit log messages to stdout.",
                        "connectorProviderClassName": "org.odpi.openmetadata.adapters.repositoryservices.auditlogstore.console.ConsoleAuditLogStoreProvider"
                    "configurationProperties": {
                        "supportedSeverities": [
        "auditTrail": [
            "Tue Dec 08 18:38:32 GMT 2020 me updated configuration for engine service asset-analysis.",
            "Tue Dec 08 18:43:47 GMT 2020 me set up default audit log destinations."

Further information

More information on the governance engines are available below:

Return to the Governance Server Types

License: CC BY 4.0, Copyright Contributors to the ODPi Egeria project.