--- sourceDocument: Brazil ServiceNow AI Platform Capabilities sourceDocumentLink: https://www.servicenow.com/docs/r/servicenow-platform Release : - brazil ft:locale : - en-US ft:publication_title : - Brazil ServiceNow AI Platform Capabilities ft:clusterId : - platcap bundleId : - platcap workflow : - Platform --- # Managing namespaces # Managing namespaces in Hermes {#ariaid-title1} Release version: Brazil Updated September 10, 2026 ![](https://www.servicenow.com/docs/portal-asset/ico-clock) 3 minutes to read Summarize ![AI sparkle icon](https://servicenow.com/docs/portal-asset/ai-sparkle-icon) Summarized using AI This content was generated using new OpenAI-powered functionality. Results are provided on an as is basis and are not guaranteed to be accurate or complete. ## Summary of Managing namespaces in Hermes Namespaces in Hermes allow ServiceNow customers to group Kafka topics logically, simplifying topic management and access control. Each Kafka topic in ServiceNow is linked to a namespace, enabling organization by factors such as Kafka cluster or ServiceNow domain. This structure is essential for managing domain-separated instances, where namespaces determine which domains can access specific topics. Show full answer Show less ## Namespaces and Topic Assignment Namespaces are stored as records in the **Kafka Namespaces \[syskafkanamespace\]** table, managed by administrators with the `kafkanamespaceadmin` role. Topics are assigned to namespaces based on their name prefixes, which correspond to namespace prefixes. A scheduled job regularly scans Hermes for new Kafka topics, creates topic records in ServiceNow, and assigns them to the appropriate namespace based on prefix matching. Prefix matching follows these rules: * The longest matching namespace prefix determines the namespace assignment. * If no specific prefix matches, the zero-length prefix of the Default Namespace applies, assigning the topic to the global domain. * If the Default Namespace is absent or altered so no match occurs, no topic record is created. ## Namespace Design Considerations * Plan namespace and topic organization before creation, as deleting a namespace requires deleting its associated topics. * In domain-separated instances, create one namespace per ServiceNow domain to maintain clear separation. * Use namespaces to segregate topics by domain and Kafka installation, ensuring proper access control and management. * Consider deleting or deactivating the Default Namespace to prevent unintended topic creation in the global domain and enforce strict prefix matching. ## Practical Actions for ServiceNow Customers * Create namespaces to organize Kafka topics logically within ServiceNow and control domain access. * Monitor and manage namespaces through the **Kafka Namespaces \[syskafkanamespace\]** table using appropriate administrative roles. * Use prefix conventions aligned with Kafka cluster names or domain identifiers to automate topic assignment to namespaces. * Review and adjust the Default Namespace configuration to avoid configuration issues related to topic placement. * Refer to related Hermes Messaging Service documentation for domain separation best practices and topic management. Group Kafka topics together for simplified topic management and access control specification using namespaces. In ServiceNow, all Kafka topics link to a namespace. You can use namespaces to organize topics in logical ways. For example, you can group topics together based on their Kafka cluster. You can also use namespaces to configure which domains can access which topics on a domain-separated instance. You assign topics to ServiceNow domains using the topic's namespace. ## Namespace records {#managing-namespaces-hermes__section_jqf_122_3zb} Namespace records are stored in the Kafka Namespaces \[sys_kafka_namespace\] table. This table shows a list of namespace records with each namespace's related topic prefix. An administrator with the kafka_namespace_admin role creates namespace records in the Kafka Namespaces \[sys_kafka_namespace\] table. ## Namespaces and topic prefixes {#managing-namespaces-hermes__section_ddm_q1d_3zb} A topic is assigned to a namespace based on the topic name's prefix. A scheduled job regularly checks Hermes for new topics. When it finds one, it creates a ServiceNow topic record for the topic and links the topic to a namespace. The prefix assigned to the topic is the basis for its namespace assignment in ServiceNow. This image shows an example of using the Kafka cluster name prefix to organize topics into different namespaces in ServiceNow. Figure 1. Kafka prefixes and topic namespaces In this example: 1. An instance administrator with the kafka_namespace_admin role creates namespace records for the Log Analysis group, the Fulfillment group, and another subsidiary in the ServiceNow instance. 2. The instance administrator works with the Kafka administrator to replicate topics to Hermes using the Kafka cluster name as the namespace prefix. 3. The Kafka cluster for the fulfillment group has a topic named `material_orders`. The topic is replicated to Hermes using `fulfillment` as the namespace prefix. A new topic is created in Hermes called `fulfillment.material_orders`. 4. A scheduled job finds the `fulfillment.material_orders` topic in Hermes, creates a topic record, and assigns the record to the Fulfillment namespace to match its prefix. {#managing-namespaces-hermes__ol_u1g_bxd_3zb} ## Prefix matching rules {#managing-namespaces-hermes__section_acy_mf2_3zb} Topic name prefixes are matched to namespaces according to the following rules. * The namespace is selected based on the longest matching namespace prefix. If there's a matching namespace, the topic record is assigned to that namespace and that namespace's domain. * If there isn't a longer namespace prefix that matches, the zero-length prefix of the Default Namespace will match. The topic record is assigned to the Default Namespace in the global domain. * If the Default Namespace has been deleted or modified, so there's no matching namespace at all, then no topic record is created. {#managing-namespaces-hermes__ul_qm4_4f2_3zb} ## Namespace design considerations {#managing-namespaces-hermes__section_s4y_czc_3zb} Plan how want to organize your namespaces and topics before you start creating them. Once you add a topic to a namespace, you can't delete the namespace without deleting the topics that are associated with it. Have a namespace for each domain on a domain-separated instance : Create one namespace per ServiceNow domain. Use namespaces to organize topics by domain and Kafka installation : Use namespaces to separate both topics that belong in separate ServiceNow domains and topics from separate Kafka installations. After you've configured your namespaces, consider deleting or deactivating the Default Namespace : Keeping the Default Namespace could lead to configuration issues, such as a mismatched topic prefix. This mismatch could result in a topic that should have been created in one domain being created in the global domain. You can enforce tighter constraints on where topics are created by deleting the Default Namespace. For example, if you decide that all topics must have a prefix that matches a namespace, deleting the Default Namespace ensures that topics without a matching prefix aren't created. For details on using domain separation with namespaces in Hermes, see [Hermes Messaging Service domain separation](https://www.servicenow.com/docs/Ctr1eGHbMpzpOBHzCQbgEg "Domain separation is supported for the Hermes Messaging Service. Domain separation enables you to separate data, processes, and administrative tasks into logical groupings called domains. You can control several aspects of this separation, including which users can see and access data."). * **[Create a namespace in Hermes](https://www.servicenow.com/docs/nPInxhY1pyjkNirlhEoQxg)** Organize your Kafka topics by creating a namespace. * **[Delete a namespace in Hermes](https://www.servicenow.com/docs/_nsSsKLXZokBQVBWC~Jnwg)** Prevent topics from being added to a namespace by deleting the namespace in Hermes. **Related concepts** * [Managing topics in Hermes](https://www.servicenow.com/docs/Ggz6BJm8b1C9gEWrTMalOQ "Manage topic records in your instance and Kafka topics in the Hermes Kafka cluster using the Hermes Messaging Service.") * [Monitoring topics in the Hermes Kafka cluster](https://www.servicenow.com/docs/XDA1DIrGTKbcFJ~7pqfQkQ "Monitor message processing and view topics in the Hermes Kafka cluster that belong to you using the Hermes Messaging Service topic inspector.")