A Server Role is a parameter that is defined in carbon.xml for WSO2 Carbon-based products. Each product has a different default ServerRoles property in its carbon.xml. The Default Server Role value for WSO2 Identity Server is IdentityServer.
Other Server Role values:
- WSO2 AppServer - "ApplicationServer"
- WSO2 BAM - "BusinessActivityMonitor"
- WSO2 BPS - "BusinessProcessServer"
- WSO2 BRS - "BusinessRulesServer"
- WSO2 DSS - "DataServicesServer"
- WSO2 ESB - "EnterpriseServiceBus"
- WSO2 GS - "GadgetServer"
- WSO2 IS - "IdentityServer"
- WSO2 MS - "MashupServer"
This property value is used for deployment of C-App archives. Generally, a C-App consists of a set of resources that is to be deployed in different products. So if a user deploys a C-App in a Carbon product, not all of the resources can be deployed in that particular product instance. To sort out which resources can be deployed and which cannot, the Server Role property is used. When a C-App is deployed, it reads the ServerRoles property in carbon.xml and deploys only the resources which match the Server Role values there.
The Server Roles Manager is a component to manage server roles property for WSO2 Carbon-based products.
As Carbon supports the adding of different product features into one product instance, the original concept of the Server Role property being added into carbon.xml is difficult to manage because users may have to manually modify carbon.xml to include the Server Roles related to the product feature they have added to a Carbon product instance.
To overcome those issues, the Server Role Manager is introduced. The Server Role Manager will store the both carbon.xml default product roles and the user/tenant-specified Server Roles in the "Configuration" registry. So when a C-App is deploying in Carbon, the C-App deployer will check for the aforementioned Server Roles from the registry instead of carbon.xml.
See also Adding a Server Role and Deleting a Server Role.