This should fix the following error:
the server closed connection before returning the first response byte. Make sure the server returns 'Connection: close' response header before closing the connection
This is a common error whith improperly configured target autodiscovery and/or relabeling.
This error leads to duplicate scraping of the same targets with the same set of labels, which leads
to duplicate samples in time series.
Previously targets with duplicate scrape urls were merged into a single line on the page.
Now each target with duplicate scrape url is displayed on a separate line.
This should reduce CPU load during scraping when target discovery generates
big number of `__meta_*` labels (for instance, k8s discovery).
See https://www.robustperception.io/life-of-a-label for details.
Prometheus docs at https://prometheus.io/docs/prometheus/latest/configuration/configuration/#scrape_config say:
> In communication with external systems, they are always applied only
> when a time series does not have a given label yet and are ignored otherwise.
Though this may result in consistency chaos when scrape targets override `external_labels`,
let's stick with Prometheus behavior for the sake of backwards compatibility.
There is last resort in vmagent with `-remoteWrite.label`, which consistently
sets the configured labels to all the metrics before sending them to remote storage.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/366
This should prevent from the following unexpected side-effects of idempotent request retries:
- increased actual timeout when scraping the target comparing to the configured scrape_timeout
- increased load on the target
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/357
