Chapter 7. Brokers page The Brokers page shows all the brokers created for a Kafka cluster. For each broker, you can see its status, as well as the distribution of partitions across the brokers, including the number of partition leaders and followers. The broker status is shown as one of the following: Not Running The broker has not yet been started or has been explicitly stopped. Starting The broker is initializing and connecting to the cluster, including discovering and joining the metadata quorum. Recovery The broker has joined the cluster but is in recovery mode, replicating necessary data and metadata before becoming fully operational. It is not serving clients. Running The broker is fully operational, registered with the controller, and actively serving client requests. Pending Controlled Shutdown The broker has initiated a controlled shutdown process and will shut down gracefully once complete. Shutting Down The broker is in the process of shutting down. Client connections are being closed, and internal resources are being released. Unknown The broker's state is unknown, possibly due to an unexpected error or failure. If the broker has a rack ID, this is the ID of the rack or datacenter in which the broker resides. Click on the right arrow (>) to a broker name to see more information about the broker, including its hostname and disk usage. Click on the Rebalance tab to show any rebalances taking place on the cluster. Note Consider rebalancing if the distribution is uneven to ensure efficient resource utilization. 7.1. Managing rebalances When you configure KafkaRebalance resources to generate optimization proposals on a cluster, you can check their status from the Rebalance tab. The Rebalance tab presents a chronological list of KafkaRebalance resources from which you can manage the optimization proposals. Note Cruise Control must be enabled to run alongside the Kafka cluster in order to use the Rebalance tab. For more information on setting up and using Cruise Control to generate proposals, see the Streams for Apache Kafka documentation . Procedure From the Streams for Apache Kafka Console, log in to the Kafka cluster, then click Brokers . Check the information on the Rebalance tab. For each rebalance, you can see its status and a timestamp in UTC. Table 7.1. Rebalance status descriptions Status Description New Resource has not been observed by the operator before PendingProposal Optimization proposal not generated ProposalReady Optimization proposal is ready for approval Rebalancing Rebalance in progress Stopped Rebalance stopped NotReady Error ocurred with the rebalance Ready Rebalance complete ReconciliationPaused Rebalance is paused Note The status of the KafkaRebalance resource changes to ReconciliationPaused when the strimzi.io/pause-reconciliation annotation is set to true in its configuration. Click on the right arrow (>) to a rebalance name to see more information about the broker, including its rebalance mode, and whether auto-approval is enabled. If the rebalance involved brokers being removed or added, they are also listed. Optimization proposals can be generated in one of three modes: full is the default mode and runs a full rebalance. add-brokers is the mode used after adding brokers when scaling up a Kafka cluster. remove-brokers is the mode used before removing brokers when scaling down a Kafka cluster. If auto-approval is enabled for a proposal, a successfully generated proposal goes straight into a cluster rebalance. Viewing optimization proposals Click on the name of a KafkaRebalance resource to see a generated optimization proposal. An optimization proposal is a summary of proposed changes that would produce a more balanced Kafka cluster, with partition workloads distributed more evenly among the brokers. For more information on the properties shown on the proposal and what they mean, see the Streams for Apache Kafka documentation . Managing rebalances Select the options icon (three vertical dots) and click on an option to manage a rebalance. Click Approve to approve a proposal. The rebalance outlined in the proposal is performed on the Kafka cluster. Click Refresh to generate a fresh optimization proposal. If there has been a gap between generating a proposal and approving it, refresh the proposal so that the current state of the cluster is taken into account with a rebalance. Click Stop to stop a rebalance. Rebalances can take a long time and may impact the performance of your cluster. Stopping a rebalance can help avoid performance issues and allow you to revert changes if needed. Note The options available depend on the status of the KafkaBalance resource. For example, it's not possible to approve an optimization proposal if it's not ready.

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