[beat] LoadMeta has a race condition.

[leehinman]

The LoadMeta function has a race condition if more than one beat has the same paths defined.

beats/libbeat/cmd/instance/beat.go

Lines 979 to 1002 in 22a9a05

	tempFile := metaPath + ".new"
	f, err = os.OpenFile(tempFile, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0o600)
	if err != nil {
	return fmt.Errorf("failed to create Beat meta file: %w", err)
	}
	encodeErr := json.NewEncoder(f).Encode(meta{UUID: b.Info.ID, FirstStart: b.Info.FirstStart})
	err = f.Sync()
	if err != nil {
	return fmt.Errorf("Beat meta file failed to write: %w", err)
	}
	err = f.Close()
	if err != nil {
	return fmt.Errorf("Beat meta file failed to write: %w", err)
	}
	if encodeErr != nil {
	return fmt.Errorf("Beat meta file failed to write: %w", encodeErr)
	}
	// move temporary file into final location
	err = file.SafeFileRotate(metaPath, tempFile)
	return err

The os.OpenFile should be replaced with os.CreateTemp

[elasticmachine]

Pinging @elastic/elastic-agent-data-plane (Team:Elastic-Agent-Data-Plane)

[cmacknz]

Is this going to hit the two metricbeat receivers we use for internal agent monitoring?

[leehinman]

Is this going to hit the two metricbeat receivers we use for internal agent monitoring?

yes, working on it now.