Relabeling rules generally have the following configuration fields, but for each type of action (relabeling rule type), only a subset of these fields are used:

action: <relabel action>
source_labels: [<source label name list>]
separator: <source labels separator>
target_label: <target label>
regex: <regular expression>
modulus: <modulus value>
replacement: <replacement string>

The fields have the following meaning:

• action: The desired relabeling action to execute. Defaults to replace. Possible actions (explained in the following sections) are:
  • replace
  • keep
  • drop
  • hashmod
  • labelmap
  • labeldrop
  • labelkeep
  • keepequal
  • dropequal
  • lowercase
  • uppercase
• source_labels: A list of label names that are concatenated using the configured separator string and matched against the provided regular expression in the regex field.
• separator: A string with which to separate source labels when concatenating them. Defaults to ";".
• target_label: The name of the label that should be overwritten when using the replace or hashmod relabel actions.
• regex: The regular expression to match against the concatenated source labels. Defaults to "(.*)", matching any source labels.
• modulus: The modulus to take of the hash of the concatenated source labels. Useful for horizontal sharding of Prometheus setups.
• replacement: A replacement string that is written to the target_label label for replace relabel actions. It can refer to regular expression capture groups that were captured by regex.