Retrieving Metrics

Cruise Control uses Kafka to store and retrieve its metrics which is read by the Metric Fetcher.

In Load Monitor, the Metric Fetcher Manager is responsible for coordinating all the sampling tasks: the Metric Sampling Task, the Bootstrap Task and the Linear Model Training Task.

Each sampling task is carried out by a configured number of Metric Fetcher threads. Each Metric Fetcher thread uses a pluggable Metric Sampler to fetch samples. Each Metric Fetcher is assigned with a few partitions in the cluster to get the samples. The metric samples are organized by the Metric Sample Aggregator that puts each metric sample into a workload snapshot according to the timestamp of a metric sample.

The cluster workload model is the primary output of the Load Monitor. The cluster workload model reflects the current replica assignment of the cluster and provides interfaces to move partitions or replicas. These interfaces are used by the Analyzer to generate optimization solutions.

The Sample Store stores the metric and training samples for future use.

With the metric sampler, you can deploy Cruise Control to various environments and work with the existing metric system.

When using Cruise Control in the Cloudera environment, HttpMetricsReporter reports metrics to the Cloudera Manager time-series database. As a result, the Kafka metrics can be read using the Cloudera Manager.