Data model

Deckhouse Prom++ stores all data as time series: streams of timestamped values belonging to a single metric and a single set of labels. In addition to stored time series, Deckhouse Prom++ can generate derived time series as a result of query execution.

Metric names and labels

Each time series is uniquely identified by its metric name and optional key-value pairs called labels.

Metric names

• Description: Specifies the general characteristics of the system being measured (for example, http_requests_total — the total number of HTTP requests received).

• Naming rules:

  • Metric names can contain ASCII letters, numbers, underscores, and colons.
  • Must match the following regular expression: [a-zA-Z_:][a-zA-Z0-9_:]*.

  Warning. Colons are reserved for user-defined rules. They should not be used in exporters or direct instrumentation.

Labels

• Description: Allow the Deckhouse Prom++ data model to identify any combination of labels for a single metric. They define the specific dimensional implementation of that metric (for example, all HTTP requests that used the POST method for the /api/tracks handler). The query language allows you to filter and aggregate data based on these dimensions.
• Naming rules:
  • Labels can contain ASCII letters, numbers, and underscores. They must match the following regular expression: [a-zA-Z_][a-zA-Z0-9_]*.
  • Label names beginning with __ (two underscores) are reserved for internal use.
  • Label values can contain any Unicode characters.
  • Labels with an empty value are considered equivalent to no label.
• Changing labels: Any change to a label value, including adding or removing labels, creates a new time series.

Samples

Samples form the actual data of time series. Each sample includes:

• Values: Floating point number (float64).
• Timestamps: Accuracy up to milliseconds.

Metric representation format

The following format is used to identify time series:

<metric name>{<label name>=<label value>, ...}

For example, a time series with the metric name api_http_requests_total and labels method=“POST” and handler=“/messages” can be written as follows:

api_http_requests_total{method=“POST”, handler="/messages"}