kubernetes/kops · error

error writing SSL certificate: %v

Error message

error writing SSL certificate: %v

What it means

Fires in Certificate.MarshalJSON when Certificate.WriteTo fails while serializing the certificate to PEM into a buffer before JSON encoding — typically because the underlying x509 certificate data cannot be encoded.

Source

Thrown at pkg/pki/certificate.go:74

				}
			}

			if err != nil {
				klog.Infof("Invalid certificate data: %q", string(b))
				return fmt.Errorf("error parsing certificate: %v", err)
			}
		}
		*c = *r
		return nil
	}
	return fmt.Errorf("unknown format for Certificate: %q", string(b))
}

func (c *Certificate) MarshalJSON() ([]byte, error) {
	var data bytes.Buffer
	_, err := c.WriteTo(&data)
	if err != nil {
		return nil, fmt.Errorf("error writing SSL certificate: %v", err)
	}
	return json.Marshal(data.String())
}

func ParsePEMCertificate(pemData []byte) (*Certificate, error) {
	cert, err := parsePEMCertificate(pemData)
	if err != nil {
		return nil, err
	}

	c := &Certificate{
		Subject:     cert.Subject,
		Certificate: cert,
		PublicKey:   cert.PublicKey,
		IsCA:        cert.IsCA,
	}
	return c, nil
}

View on GitHub (pinned to 4c8573c808)

Solutions

1. Inspect the wrapped %v error to find the underlying WriteTo failure
2. Ensure the Certificate was successfully parsed/issued and is not internally corrupt
3. Re-issue the certificate if its stored x509 data is invalid

When it happens

Trigger: Thrown at pkg/pki/certificate.go:74 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• SSL/TLS and certificate errors — how TLS handshakes and certificate validation fail.

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/d5d1570d06b2a61e. Report an issue: GitHub.