# Monitor Clients with Confluent Control Center The information on this page helps you configure a robust performance monitoring system with Control Center. Considerations: : - You must run Control Center in [Normal mode](../overview.md#normal-mode) to get client metrics. - If you are running Control Center in [Reduced infrastructure mode](../overview.md#reduced-infra-mode), you cannot view client metrics. - You must set up your cluster for Control Center client monitoring. For more information, see the following Prerequisites section. ## Prerequisites - Control Center running in normal mode - Minimum required Confluent Platform is 8.0 or higher - Minimum required client versions are Java client 3.7.2+ and librdkafka clients 2.6+ - Enable Telemetry Reporter on Confluent Platform - Before you can monitor clients with Control Center, you must make configurations to the cluster you monitor. For more information, see [Configure Cluster for Confluent Control Center Client Monitoring](cluster-configuration.md#cluster-configure-clients-c3). ## Monitor clients with Control Center **Clients** in Control Center are organized into the principal groups. You can view the client metrics that are aggregated within a principal. You can also filter for unsupported client versions. **To view and monitor clients**: 1. Browse to the cluster and click **Clients**. 2. For a specific principal, click the **Producers**, **Consumers**, or **Consumer lag** tabs to see applicable clients in the category. For each principal, aggregate client metrics are displayed. 3. To see consumer lag information, click the **Consumer lag** tab. Consumer lag refers to the delay between the production and consumption of messages in Kafka, which can significantly impact your system’s overall performance. For details about monitoring consumer lag, see [Monitor consumer lag](consumers.md#c3-cg-view-consumer-lag). 4. Expand one or all principals to see clients for the principal. For each producer client, you see the following metrics: * Request latency: request latency in milliseconds for a node. * Throttle time: time in milliseconds a request was throttled by the broker. * Queue time: maximum time in milliseconds record batches spent in the send buffer. * bufferpool-wait-ratio: fraction of time an appender waits for space allocation. ## Monitor unsupported client versions Use **Clients** to check if you are using an unsupported client version. It is recommended that you update your client versions regularly to avoid undesired behavior in your clusters. Some issues that can arise from running unsupported client versions are: * Security vulnerabilities: unsupported client versions means that you may be missing critical security updates, leaving your applications and data vulnerable to potential security threats or exploits. * Missing features and improvements: Newer versions of client libraries often introduce new features, performance improvements, and bug fixes. * Potential service disruptions: Control Center may introduce changes or updates that are designed to work with supported client versions. Using an unsupported client version could lead to service disruptions or unexpected behavior when such changes are made. To ensure a stable, secure, and well-supported experience with Control Center, it is highly recommended that you use the officially supported client versions for your specific programming language or framework. See the [version supportability guide](https://docs.confluent.io/platform/current/installation/versions-interoperability.html) for the supported client versions and their compatibility with Control Center services and features.​​​​​​​​​​​​​​​​ Considerations: : - To filter down to only clients that have produced/consumed a message in the last 10 minute, select **Show clients with traffic only** - Yellow warning icons indicate principals containing unsupported clients - To view unsupported clients associated with the yellow warning icons, click the dropdown arrow - Green status indicates supported versions - Yellow status indicates unsupported versions - Some clients report “unknown” as the version because those clients do not emit the ApiVersion - Locate the unsupported version and update the client **To monitor clients versions:** 1. Select your cluster name. 2. Click **Clients**, and navigate to the **Producer** or **Consumer** tab depending on which clients you would like to view.