Emitting Software Metrics

Beginning with the Newton (6.1.0) release, the ironic services
support emitting internal performance data to statsd. This allows operators
to graph and understand performance bottlenecks in their system.

This guide assumes you have a statsd server setup. For information on
using and configuring statsd, please see the statsd README and
documentation.

These performance measurements, herein referred to as “metrics”, can
be emitted from the Bare Metal service, including ironic-api,
ironic-conductor, and ironic-python-agent. By default, none of the
services will emit metrics.

Configuring
the Bare Metal Service to Enable Metrics

Enabling
metrics in ironic-api and ironic-conductor

The ironic-api and ironic-conductor services can be configured to
emit metrics to statsd by adding the following to the ironic
configuration file, usually located at
/etc/ironic/ironic.conf:

[metrics]
backend = statsd

If a statsd daemon is installed and configured on every host running
an ironic service, listening on the default UDP port (8125), no further
configuration is needed. If you are using a remote statsd server, you
must also supply connection information in the ironic configuration
file:

[metrics_statsd]
# Point this at your environments' statsd host
statsd_host = 192.0.2.1
statsd_port = 8125

Enabling metrics in
ironic-python-agent

The ironic-python-agent process receives its configuration in the
response from the initial lookup request to the ironic-api service. This
means to configure ironic-python-agent to emit metrics, you must enable
the agent metrics backend in your ironic configuration file on all
ironic-conductor hosts:

[metrics]
agent_backend = statsd

In order to reliably emit metrics from the ironic-python-agent, you
must provide a statsd server that is reachable from both the configured
provisioning and cleaning networks. The agent statsd connection
information is configured in the ironic configuration file as well:

[metrics_statsd]
# Point this at a statsd host reachable from the provisioning and cleaning nets
agent_statsd_host = 198.51.100.2
agent_statsd_port = 8125

Types of Metrics Emitted

The Bare Metal service emits timing metrics for every API method, as
well as for most driver methods. These metrics measure how long a given
method takes to execute.

A deployer with metrics enabled should expect between 100 and 500
distinctly named data points to be emitted from the Bare Metal service.
This will increase if the metrics.preserve_host option is set to true or
if multiple drivers are used in the Bare Metal deployment. This estimate
may be used to determine if a deployer needs to scale their metrics
backend to handle the additional load before enabling metrics. To see
which metrics have changed names or have been removed between releases,
refer to the ironic release
notes.

The ironic-python-agent ramdisk emits timing metrics for every API
method.

Deployers who use custom HardwareManagers can emit custom metrics for
their hardware. For more information on custom HardwareManagers, and
emitting metrics from them, please see the ironic-python-agent documentation <>.

Adding New Metrics

If you’re a developer, and would like to add additional metrics to
ironic, please see the ironic-lib developer documentation <>
for details on how to use the metrics library. A release note should
also be created each time a metric is changed or removed to alert
deployers of the change.