VictoriaMetrics/VictoriaMetrics · error

`target_label` must be set for `action=keep_if_contains`

Error message

`target_label` must be set for `action=keep_if_contains`

What it means

`action=keep_if_contains` keeps the target label's value only when it contains all values of the given source labels, so `target_label` is required. The parser rejects the config if `target_label` is empty for this action.

Source

Thrown at lib/promrelabel/config.go:293

			return nil, fmt.Errorf("`replacement` cannot be used with `action=graphite`; see https://docs.victoriametrics.com/victoriametrics/vmagent/#graphite-relabeling")
		}
		if rc.Regex != nil {
			return nil, fmt.Errorf("`regex` cannot be used for `action=graphite`; see https://docs.victoriametrics.com/victoriametrics/vmagent/#graphite-relabeling")
		}
	case "replace":
		if targetLabel == "" {
			return nil, fmt.Errorf("missing `target_label` for `action=replace`")
		}
	case "replace_all":
		if len(sourceLabels) == 0 {
			return nil, fmt.Errorf("missing `source_labels` for `action=replace_all`")
		}
		if targetLabel == "" {
			return nil, fmt.Errorf("missing `target_label` for `action=replace_all`")
		}
	case "keep_if_contains":
		if targetLabel == "" {
			return nil, fmt.Errorf("`target_label` must be set for `action=keep_if_contains`")
		}
		if len(sourceLabels) == 0 {
			return nil, fmt.Errorf("`source_labels` must contain at least a single entry for `action=keep_if_contains`")
		}
		if rc.Regex != nil {
			return nil, fmt.Errorf("`regex` cannot be used for `action=keep_if_contains`")
		}
	case "drop_if_contains":
		if targetLabel == "" {
			return nil, fmt.Errorf("`target_label` must be set for `action=drop_if_contains`")
		}
		if len(sourceLabels) == 0 {
			return nil, fmt.Errorf("`source_labels` must contain at least a single entry for `action=drop_if_contains`")
		}
		if rc.Regex != nil {
			return nil, fmt.Errorf("`regex` cannot be used for `action=drop_if_contains`")
		}
	case "keep_if_equal":

View on GitHub (pinned to 5079fb58f1)

Solutions

1. Set `target_label` to the label whose value should be checked/kept
2. Use `action=keep` with a regex if you want sample-level filtering instead
3. Ensure YAML keys belong to the same list item

Example fix

// before
- action: keep_if_contains
  source_labels: [pod]
// after
- action: keep_if_contains
  target_label: pod
  source_labels: [pod]

def validate_relabel(cfg):
    if cfg.get('action') == 'keep_if_contains' and not cfg.get('target_label'):
        raise ValueError('target_label must be set for action=keep_if_contains')
    return True

When it happens

Trigger: ParseRelabelConfigs (or newTestRegexRelabelConfig) is given a config with `action: keep_if_contains` and an empty `target_label`.

Common situations: Writing a keep_if_contains rule thinking it filters whole samples and thus omitting target_label; copy from graphite-style rules which don't use target_label.

Related errors

• `target_label` cannot be used with `action=graphite`; see ht
• `replacement` cannot be used with `action=graphite`; see htt
• `regex` cannot be used for `action=graphite`; see https://do
• missing `target_label` for `action=replace`
• missing `source_labels` for `action=replace_all`

AI-assisted analysis of VictoriaMetrics/VictoriaMetrics@5079fb58f1 (2026-09-03). Data as JSON: /api/errors/96292e2fcc23e6d1. Report an issue: GitHub.