Automatically generated labels and time series
When Prometheus scrapes a target, it attaches some labels automatically to the scraped time series which serve to identify the scraped target:
job: The configured job name that the target belongs to.
instance: The <host>:<port> part of the target's URL that was scraped.
If either of these labels are already present in the scraped data, the behavior depends on the honor_labels configuration option. See the scrape configuration documentation for more information.
For each instance scrape, Prometheus stores a sample in the following time series:
up{job="<job-name>", instance="<instance-id>"}: 1 if the instance is healthy, i.e. reachable, or 0 if the scrape failed.
scrape_duration_seconds{job="<job-name>", instance="<instance-id>"}: duration of the scrape.
scrape_samples_post_metric_relabeling{job="<job-name>", instance="<instance-id>"}: the number of samples remaining after metric relabeling was applied.
scrape_samples_scraped{job="<job-name>", instance="<instance-id>"}: the number of samples the target exposed.
scrape_series_added{job="<job-name>", instance="<instance-id>"}: the approximate number of new series in this scrape. New in v2.10
The up time series is useful for instance availability monitoring.