Process Engine configuration parameters

Property prefixes (unibpm.*), Kafka topic names, and module names such as unibpm-camunda8-adapter are technical identifiers from the shared codebase. The product name is Cabinee.

Scope

This document describes configuration parameters of the process engine and the components Cabinee uses to work with it.

You configure unibpm-app (Cabinee backend), unibpm-camunda8-adapter, and unibpm-camunda8-exporter; the orchestration cluster itself is configured with standard Camunda variables.

Format

The tables below use the following conventions:

• Prefix — the common prefix of a parameter group (for example, spring.datasource).
• Parameter — the parameter name within the group.
• Default value — the value used in the distribution configuration (unless overridden).

1. Enabling the engine

Configured in unibpm-app.

The property is required and has no default equal to 8: Camunda 8 components are declared with @ConditionalOnProperty(... havingValue = "8"), and without the property none of them are created in the application context.

A ready-made settings block lives in engine.yaml inside the unibpm-app artifact, but that file is not imported automatically. Either import it explicitly:

SPRING_CONFIG_IMPORT=classpath:engine.yaml
UNIBPM_ENGINE_VERSION=8

or set unibpm.engine.version: 8 directly in the deployment application.yaml. If you skip this, the application starts without errors but uses the legacy EngineService implementation and will not talk to the orchestration cluster.

2. Camunda 8 client configuration (camunda-eight-client.*)

Configured in unibpm-app. Defines how the application calls the Camunda 8 REST API v2.

2.1. Connection

2.2. Multi-tenancy

Cabinee passes the space identifier as the tenant. This is correct only when Camunda multi-tenancy is enabled and each space is registered as a tenant. Until then, force-default-tenant must remain true, otherwise the cluster responds with 400 multi-tenancy is disabled on every command.

2.3. Authorization

The registration is resolved at request time, not at application start. A missing registration appears as Could not find ClientRegistration with id ... on the first engine call, not as a startup error. If the cluster is started with CAMUNDA_SECURITY_AUTHENTICATION_UNPROTECTEDAPI=true, the token is ignored anyway — in that case set oauth2-enabled: false.

2.4. Linking a ticket to a process instance

2.5. Automatic tasks (jobs)

The mechanism is disabled by default and is not battle-tested in production. It requires both enabled: true and a non-empty jobs.types — with an empty list the worker ends its cycle without activating anything. Details: External tasks .

3. unibpm-camunda8-adapter configuration

A separate service that reads the engine record stream from Kafka. By default it listens on port 8090: 8080 is used by the orchestration cluster.

3.1. Database

Stores the processInstanceKey → businessKey mapping. Schema camunda8_adapter is created by an init script; ddl-auto remains none.

3.2. Kafka topics

The last two values must match camunda-kafka-import.change-state-topic and camunda-kafka-import.user-task-event-topic in unibpm-app. A mismatch fails silently: the adapter publishes to a topic nobody reads, and tickets simply do not change state.

3.3. Record processing

Zeebe delivers records at least once, so after a partition leader change some records arrive again. The deduplication window is in-memory and is lost when the adapter restarts: it covers failover redelivery, not a long outage. A record is marked processed only after successful handling, so a database failure does not drop the event.

4. unibpm-camunda8-exporter configuration

The exporter is loaded into the Zeebe broker JVM and configured with the broker’s own environment variables.

The list of exported record types (valueTypes) and extra producer properties (producerProperties) are non-scalar, so they are set only in the broker YAML configuration, not via environment variables:

zeebe:
  broker:
    exporters:
      unibpm:
        className: com.reunico.unibpm.camunda8.exporter.UniBpmExporter
        jarPath: /usr/local/camunda/exporters/unibpm-camunda8-exporter.jar
        args:
          bootstrapServers: kafka:29092
          topic: reunico.unibpm.c8.records
          valueTypes: [ PROCESS_INSTANCE, USER_TASK, VARIABLE, INCIDENT, JOB ]

The default valueTypes matches the example, so most deployments do not need to set it.

Important constraints when configuring:

• the exporter must be built for the broker version at least matching on the minor part — otherwise the broker fails at start with NoSuchMethodError;
• types VARIABLE and PROCESS_INSTANCE must not be excluded: the adapter takes businessKey from the former and parent-instance / completion data from the latter;
• Camunda’s built-in Elasticsearch exporter must not be disabled: Operate, Tasklist, and all /v2/*/search endpoints depend on it.