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monasca-agent/docs/MonascaMetrics.md

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Table of Contents

Nature of Metrics

In Monasca, a metric type is uniquely identified by a name and a specific set of dimensions. The set of dimensions of a metric are a dictionary of (key, value) pairs. A measurement is a metric instance with a value and a timestamp. Measurements are searchable from the Monasca API by name and dimension (key, value).

Optionally, a measurement may also contain extra data about the value, which is known as value_meta. value_ meta is a dictionary of (key, value) pairs that contain textual data that relates to the value of the measurement. If value_meta is included with a measurement, it is returned when the measurement is read via the Monasca API. Unlike dimensions, value_meta is not searchable from the Monasca API, and it is ignored when computing statistics on measurements such as average.

Naming conventions

Common Naming Conventions

Metric Names

Although metric names in the Monasca API can be any string the Monasca Agent uses several naming conventions as follows:

  • All lowercase characters.
  • '.' is used to hierarchically group. This is done for compatibility with Graphite which assumes a '.' as a delimiter.
  • '_' is used to separate words in long names that are not meant to be hierarchical.

System Dimensions

Dimensions are a dictionary of (key, value) pairs that can be used to describe metrics. Dimensions are supplied to the API by the Agent.

This section documents some of the common naming conventions for dimensions that should observed by the monitoring agents/checks to improve consistency and make it easier to create alarms and perform queries.

The agent will automatically add a hostname dimension; beyond that, dimensions are optional. Dimensions can be defined in the primary agent config and applied to all metrics, set per plugin configuration or set during collection.

The order of precedence (high to low) for all dimensions is:

  1. Any dimension defined in an Agent plugin config file.

  2. Any dimension defined in the Agent config file.

  3. Any default dimension set in the plugin code itself.

If a dimension is defined in more than one place, the dimension will be set to the value of the highest precedence above. This allows dimensions to be overridden at any level, if desired.

Common Dimensions

Name Description
hostname The FQDN of the host being measured.
observer_host The FQDN of the host that runs a check against another host.
url In the case of the http endpoint check the url of the http endpoint being checked.
device The device name
service The service name that owns this metric
component The component name within the device that the metric comes from

One way to add additional dimensions for all metrics is by using the --dimensions command line option to monasca-setup. This will populate /etc/monasca/agent/agent.yaml with dimensions to be included with all metrics. The syntax is a comma separated list of name/value pairs, 'name:value,name2:value2'

/etc/monasca/agent/agent.yaml

Main:
  dimensions:
    service: monitoring
  hostname: mini-mon
Component Default Dimensions
Component Name Dimensions
Collector component:monasca-agent
Kafka Consumer component:kafka, service:kafka
LibVirt device:disk[0].device, device:vnic[0].name
WMI Check tag from the result if there's a tag_by value (e.g.: "name:jenkins")
Zookeeper component:zookeeper, service:zookeeper
Redis redis_host: localhost, redis_port: port

OpenStack Specific Naming Conventions

This section documents some of the naming conventions that are used for monitoring OpenStack.

Metric Names

Where applicable, each metric name will list the name of the service (e.g. "compute"), component (e.g. nova-api) and the check (e.g. "process_exists"). For example, "nova.api.process_exists".

Dimensions

This section documents dimensions that are commonly used in monitoring OpenStack.

Name Description Examples
region An OpenStack region. uswest and useast
zone An OpenStack zone Examples include 1, 2 or 3
service The name of the OpenStack service being measured. compute or image or monitoring
component The component in the OpenStack service being measured. nova-api, nova-scheduler, mysql or rabbitmq.
resource_id The resource ID of an OpenStack resource.
tenant_name The tenant name of the owner of an OpenStack resource.

Cross-Tenant Metric Submission

If the owner of the VM is to receive his or her own metrics, the Agent needs to be able to submit metrics on their behalf. This is called cross-tenant metric submission. To be allowed to do that, the Agent's Keystone username and project (tenant) has to be assigned to one of the delegate_authorized_roles. The authorized roles are configured in monasca-api. The Agent's username is contained as username in /etc/monasca/agent/agent.yaml, and passed to monasca-setup as the -u parameter. The Agent's project name is also contained in agent.yaml as project_name, and passed to monasca-setup as the --project-name parameter.

In the below example, the Agent's Keystone username is "monasca-agent" and the Agent's Keystone project name is "mini-mon".

Example commands to add the Agent user/project to the monitoring-delegate role:

$ openstack role create monitoring-delegate
$ openstack role add --user monasca-agent --project mini-mon monitoring-delegate

Once the Agent's user and project are assigned to the monitoring-delegate group, the Agent can submit metrics for other tenants.

StatsD

The Monasca Agent ships with a StatsD daemon implementation. A StatsD client can be used to send metrics to the Forwarder via the StatsD daemon.

monasca-statsd will accept counters, gauges and timing values following the standard StatsD protocol. Dimensions are supported and compatible with the DogStatsD extension for tags. Support for the monasca-statsd Python client library is deprecated and might be removed in the future.

Statsd metrics are not bundled along with the metrics gathered by the Collector, but are flushed to the agent Forwarder on a separate schedule (every 10 seconds by default, rather than 60 seconds for Collector metrics).

Here is an example of metrics submitted using the standard statsd Python client library.

import statsd

statsd.increment('processed', 5)        # Increment 'processed' metric by 5
statsd.timing('pipeline', 2468.34)      # Pipeline took 2468.34 ms to execute
statsd.gauge('gaugething', 3.14159265)  # 'gauge' would be the preferred metric type for Monitoring

StatsD Protocol Compatibility

The monasca-statsd daemon supports the following parts of the StatsD protocol and its extensions:

StatsD 1.0

  • counters
  • gauges
  • timings (no histograms)

DogStatsD

  • dimensions/tags (key:value, tags without value will be mapped to <tag>:True)

Monasca

  • rates

Examples

The monasca-statsd library provides a Python-based implementation of a statsd client but also adds the ability to add dimensions to the statsd metrics for the client.

Here are some examples of how code can be instrumented using calls to monasca-statsd.

  • Import the module once it's installed.

    from monascastatsd import monasca_statsd
statsd = monasca_statsd.MonascaStatsd()

  • Optionally, configure the host and port if you're running Statsd on a non-standard port.

    statsd.connect('localhost', 8125)

  • Increment a counter.

    statsd.increment('page_views')

With dimensions:
    statsd.increment('page_views', 5, dimensions={'Hostname': 'prod.mysql.abccorp.com'})

  • Record a gauge 50% of the time.

    statsd.gauge('users_online', 91, sample_rate=0.5)

With dimensions:
    statsd.gauge('users_online', 91, dimensions={'Origin': 'Dev', 'Environment': 'Test'})

  • Time a function call.

    @statsd.timed('page.render')
def render_page():
    # Render things...

  • Time a block of code.

    with statsd.time('database_read_time',
                 dimensions={'db_host': 'mysql1.mycompany.net'}):
# Do something...

License

(C) Copyright 2015-2016 Hewlett Packard Enterprise Development LP