How to execute multiple queries in one call in Prometheus

user_2604630 0
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I'm running prometheus inside kubernetes cluster.

I need to send queries to Prometheus every minute, to gather information of many metrics from many containers. There are too match queries, so I must combine them.

I know how I can ask Prometheus for one metric information on multiple containers: my_metric{container_name=~"frontend|backend|db"} , but I haven't found a way to ask Prometheus for multiple metric information in one query.

I'm looking for the equivalent to 'union' in sql queries.

prometheus
3 Answers

I found here this solution: {__name__=~"metricA|metricB|metricC",container_name=~"frontend|backend|db"}.

user_26046300

You can use the or operator, however this does not generalise as it ignores metric names. I'd suggest making multiple queries to the API.

user_835910

PromQL doesn't provide the ability to execute multiple queries in a single api call. But MetricsQL, which is backwards-compatible to PromQL, provides such an ability via union function:

union(
  query1,
  query2,
  ...
  queryN,
)

This returns all the time series from all the query* queries. Note that it is expected that each time series has an unique set of labels (including metric name aka ___name__ label). If this isn't the case, then duplicate series with identical labelsets will be removed from the result. In this case the alias and label_set functions may be useful for adding unique labels per query*.

user_2749370
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