Netflix/chaosmonkey · warning

failed to close response body from

Error message

failed to close response body from %s

What it means

This deferred error fires when resp.Body.Close() fails inside OtherID, but only when the rest of OtherID completed without error (cerr != nil && err == nil). The GET for the instance's alternate ID otherwise succeeded; only connection teardown failed. Because OtherID uses a named return, this close error replaces the successful result with an error, which then surfaces wrapped as "retrieve other id failed" in Execute.

Solutions

1. Check whether the underlying data was still correct; if so, this is a teardown artifact — drain the body before closing to reduce it.
2. Use io.Copy(io.Discard, resp.Body) before Close, or ensure full reads (the code already does ioutil.ReadAll, so check for early-return paths).
3. Tune http.Transport keepalive settings (IdleConnTimeout, MaxIdleConnsPerHost) to avoid stale connections.
4. Correlate errors.Cause with LB/Gate logs for connection resets.
5. If it persists and blocks terminations, consider ignoring close errors on GET responses whose body was fully read.

Example fix

// before
if cerr := resp.Body.Close(); cerr != nil && err == nil {
	err = errors.Wrap(cerr, fmt.Sprintf("failed to close response body from %s", url))
}
// after
// body fully read above; treat close error as non-fatal
_ = resp.Body.Close()

// body is fully read via ioutil.ReadAll before close; drain defensively on early-return paths
io.Copy(io.Discard, resp.Body)

otherID, err := spinnaker.OtherID(ins)
if err != nil {
	if strings.Contains(err.Error(), "failed to close response body") {
		log.Printf("non-fatal close error looking up %s: %v", ins.ID(), err)
		// data was fine; retry or proceed per policy
	}
	return errors.Wrap(err, "retrieve other id failed")
}

When it happens

Trigger: GET to the Spinnaker instance endpoint succeeded and the body was read, but resp.Body.Close() returned an error — typically a reset/aborted keepalive connection during teardown.

Common situations: Server or LB closing keepalive connections aggressively; stale pooled connections in http.Transport; network device interrupting idle connections between request completion and close.

Related errors

• body close failed at
• failed to close response body of
• body read failed at
• body read failed at
• failed to read response body

AI-assisted analysis of Netflix/chaosmonkey@eaa28fb761 (2026-09-03). Data as JSON: /api/errors/dadaf6bd858679a7. Report an issue: GitHub.

Appendix: source

Thrown at spinnaker/terminator.go:152

		log.Fatalf("chronos.jsonPayload could not marshal data into json: %v", err)
	}

	return result
}

// OtherID returns the alternate instance id of an instance, if it exists
// If there is no alternate instance id, it returns an empty string
// This is used by Titus, where we also report the uuid
func (s Spinnaker) OtherID(ins chaosmonkey.Instance) (otherID string, err error) {
	url := s.instanceURL(ins.AccountName(), ins.RegionName(), ins.ID())
	resp, err := s.client.Get(url)
	if err != nil {
		return "", errors.Wrap(err, fmt.Sprintf("get failed on %s", url))
	}

	defer func() {
		if cerr := resp.Body.Close(); cerr != nil && err == nil {
			err = errors.Wrap(cerr, fmt.Sprintf("failed to close response body from %s", url))
		}
	}()

	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return "", errors.Wrap(err, fmt.Sprintf("body read failed at %s", url))
	}

	// Example of response body:
	/*
		{
			...
			"health": [
				{
					"type": "Titus",
					"healthClass": "platform",
					"state": "Up"
				},

View on GitHub (pinned to eaa28fb761)