- Metrics Sink Configuration
- Metric Types
- Master Web UI Metrics
Metrics provide insight into what is going on in the cluster. They are an invaluable resource for monitoring and debugging. Alluxio has a configurable metrics system based on the Coda Hale Metrics Library. In the metrics system, sources generate metrics, and sinks consume these metrics. The metrics system polls sources periodically and passes metric records to sinks.
Alluxio’s metrics are partitioned into different instances corresponding to Alluxio components. Within each instance, users can configure a set of sinks to which metrics are reported. The following instances are currently supported:
- Master: The Alluxio master process.
- Worker: The Alluxio worker process.
- Client: Any process with the Alluxio client library.
Metrics Sink Configuration
A sink specifies where metrics are delivered to. Each instance can report to zero or more sinks.
ConsoleSink: Outputs metrics values to the console.
CsvSink: Exports metrics data to CSV files at regular intervals.
JmxSink: Registers metrics for viewing in a JMX console.
GraphiteSink: Sends metrics to a Graphite server.
MetricsServlet: Adds a servlet in Web UI to serve metrics data as JSON data.
The metrics system is configured via a configuration file that Alluxio expects to be present at
A custom file location can be specified via the
alluxio.metrics.conf.file configuration property.
Alluxio provides a
metrics.properties.template under the
conf directory which includes all configurable properties
and guidance of how to specify each property.
Default HTTP JSON Sink
MetricsServlet is enabled in Alluxio leading master and workers.
You can send an HTTP request to
/metrics/json/ of the Alluxio leading master to get a snapshot of all metrics in JSON format.
Metrics on the Alluxio leading master contains its own instance metrics and a summary of the cluster-wide aggregated metrics.
# Get the metrics in JSON format from Alluxio leading master $ curl <LEADING_MASTER_HOSTNAME>:<MASTER_WEB_PORT>/metrics/json # For example, get the metrics from master process running locally with default web port $ curl 127.0.0.1:19999/metrics/json/
Send an HTTP request to
/metrics/json/ of the active Alluxio workers to get per-worker metrics.
# Get the metrics in JSON format from an active Alluxio worker $ curl <WORKER_HOSTNAME>:<WORKER_WEB_PORT>/metrics/json # For example, get the metrics from worker process running locally with default web port $ curl 127.0.0.1:30000/metrics/json/
Sample CSV Sink Setup
This section gives an example of writing collected metrics to a CSV file.
First, create the polling directory for
CsvSink (if it does not already exist):
$ mkdir /tmp/alluxio-metrics
In the metrics property file,
$ALLUXIO_HOME/conf/metrics.properties by default, add the following properties:
# Enable CsvSink sink.csv.class=alluxio.metrics.sink.CsvSink # Polling period for CsvSink sink.csv.period=1 sink.csv.unit=seconds # Polling directory for CsvSink, ensure this directory exists! sink.csv.directory=/tmp/alluxio-metrics
If Alluxio is deployed in a cluster, this file needs to be distributed to all the nodes. Restart the Alluxio servers to active new configuration changes.
After starting Alluxio, the CSV files containing metrics will be found in the
The filename will correspond with the metric name.
metrics.properties.template for all possible sink specific configurations.
Each metric falls into one of the following metric types:
- Gauge: Records a value
- Meter: Measures the rate of events over time (e.g., “requests per minute”)
- Counter: Measures the number of times an event occurs
- Timer: Measures both the rate that a particular event is called and the distribution of its duration
For more details about the metric types, please refer to the metrics library documentation
Master Web UI Metrics
Besides the raw metrics shown via metrics servlet or custom metrics configuration, users can view more human-readable metrics stored in the leading master via leading master web UI metrics page.
The nick name and original metric name corresponding are shown:
|Nick Name||Original Metric Name|
|Local Alluxio (Domain Socket) Read||cluster.BytesReadDomain|
|Local Alluxio (Domain Socket) Write||cluster.BytesWrittenDomain|
|Local Alluxio (Short-circuit) Read||cluster.BytesReadLocal|
|Local Alluxio (Short-circuit) Write||cluster.BytesWrittenLocal|
|Remote Alluxio Read||cluster.BytesReadAlluxio|
|Remote Alluxio Write||cluster.BytesWrittenAlluxio|
|Under Filesystem Read||cluster.BytesReadUfsAll|
|Under Filesystem Write||cluster.BytesWrittenUfsAll|
Detailed descriptions of those metrics are in cluster metrics.
Mounted Under FileSystem Read shows the
cluster.BytesReadPerUfs.UFS:<UFS_ADDRESS> of each Alluxio UFS.
Mounted Under FileSystem Write shows the
cluster.BytesWrittenPerUfs.UFS:<UFS_ADDRESS> of each Alluxio UFS.
Logical Operations and
RPC Invocations present parts of the master metrics.