* new feature: relabel logging
Use scrape_configs[x].relabel_debug = true to log metric names inkl.
labels before and after relabeling. After relabeling related metrics
get dropped, i.e. not submitted to servers.
* vminsert wants relabel logging, too.
* Add omitempty for DisableCompression and DisableKeepAlive fields in ScrapeConfig
* Add omitempty annotation to all the default/optional values
* Fix annotations after review
These actions may be useful for filtering out unneeded targets and/or metrics if they contain equal label values.
For example, the following rule would leave the target only if __meta_kubernetes_annotation_prometheus_io_port
equals __meta_kubernetes_pod_container_port_number:
- action: keep_if_equal
source_labels: [__meta_kubernetes_annotation_prometheus_io_port, __meta_kubernetes_pod_container_port_number]