prometheus.md

Prometheus

• translating-between-monitoring-languages https://www.robustperception.io/translating-between-monitoring-languages/
• Turning complete https://www.robustperception.io/conways-life-in-prometheus/

Translating between monitoring languages

A comparison from Prometheus guys https://www.robustperception.io/translating-between-monitoring-languages/

Start and end

• Graphite: from, until
• PromQL: start, end
• InfluxQL: where clause on time

Graphite have color and stacked

Syntax

• Graphite: nested prefix function
• PromQL: C expression like
• InfluxQL: SQL-like

Math

Adding 1 to all values across a set of time series

• Graphite: offset(seriesname.*, 1)
• InfluxQL: SELECT 1 + "value" FROM "seriesname"
  • NOTE: InfluxQL need to specify value because it support multiple fields
• PromQL: seriesname + 1

Arithmetic operations

• Graphite: invert, scale, pow
• PromQL: +, -, *, /, %
• InfluxQL: +, -, *, /

Functions

• Graphite: logarithm(seriesname.*, 1)
• InfluxQL:
  • TODO: the blog say it does not support function
  • But I found https://docs.influxdata.com/influxdb/v1.2/query_language/functions/ , e... ceiling point to an issue
  • And there is a issue influxdata/influxdb#5930, seems most of these functions are not implemented
  • Custom script support calling all go functions https://docs.influxdata.com/kapacitor/v1.2/tick/expr/#math-functions
• PromQL:
  • https://prometheus.io/docs/querying/functions/
  • day_of_month etc.

Select

• Graphite: seriesname.filter
• InfluxQL: SELECT "value" FROM "seriesnamne" WHERE tag="filter"
• PromQL: seriesnamne{labelname="filter"}

Working Across Series

• Graphite: averageSeries(seriesname.*)
• InfluxQL: SELECT MEAN("value") FROM "seriesname"
• PromQL: avg(seriesname)
  • https://prometheus.io/docs/querying/operators/#aggregation-operators
• TODO: it seems to be the group by, like I have tags like application, region, instances, now I want to group by region, and use average for all the instances in the same region

Skipped

• Range, Number of Unique Values, Mode?
• Histogram https://prometheus.io/docs/practices/histograms/

Working Across Time

• moving average

Prediction

• Graphite: Holt-Winters
  • http://graphite.readthedocs.io/en/latest/functions.html#graphite.render.functions.holtWintersForecast
• InfluxQL: Holt-Winters
  • https://docs.influxdata.com/influxdb/v1.2/query_language/functions/#holt-winters
• PromQL:
  • https://prometheus.io/docs/querying/functions/#holt_winters
  • https://prometheus.io/docs/querying/functions/#predict_linear

Binary Operators

math between two different series

• Graphite: reduceSeries(my.*, "diffSeries", 1, "a", "b")
• InfluxQL fields: SELECT "a" - "b" FROM "table"
• InfluxQL measurements: Not supported
  • TICK script does https://docs.influxdata.com/kapacitor/v1.2/nodes/join_node/
• PromQL: my_a - my_b