Error response format

Quake AI APIs return structured error details in every non-2xx response. The exact format depends on the service: OpenStack APIs return JSON, the S3-compatible interface returns XML, and compute instances expose fault objects for ERROR-state diagnostics. This page documents each format so you can parse errors programmatically and collect the right evidence for support.

OpenStack JSON error format#

All OpenStack APIs (Compute, Network, Block Storage) return errors as JSON objects. The outer key is a camelCase name derived from the HTTP status reason phrase, wrapping code and message fields.

Standard format#

{
  "badRequest": {
    "code": 400,
    "message": "Invalid input for field/attribute name. Value: 123. 'name' must be a string."
  }
}

Common outer keys by status code#

Service-specific variations#

Network (Neutron) uses a flat structure with a NeutronError type field:

{
  "NeutronError": {
    "type": "IpAddressGenerationFailure",
    "message": "No more IP addresses available on network ...",
    "detail": ""
  }
}

Block Storage (Cinder) follows the standard format but may include retryAfter on 413 responses:

{
  "overLimit": {
    "code": 413,
    "message": "VolumeLimitExceeded: Maximum number of volumes allowed (500) exceeded.",
    "retryAfter": 0
  }
}

Compute fault object#

When a compute instance enters the ERROR state, the server response includes a fault object that persists until the instance is rebuilt or deleted. This is separate from the HTTP error response; it is part of the instance's data.

Retrieving the fault#

openstack server show YOUR_INSTANCE_ID -c fault -f json

Or via the API:

curl -s -H "X-Auth-Token: $OS_TOKEN" \
  "$OS_COMPUTE_URL/v2.1/servers/YOUR_INSTANCE_ID" \
  | python3 -c "import sys,json; print(json.dumps(json.load(sys.stdin)['server'].get('fault',{}), indent=2))"

Fault object structure#

{
  "fault": {
    "message": "No valid host was found.",
    "code": 500,
    "created": "2026-04-01T12:00:00Z"
  }
}

The fault message field is the single most useful diagnostic artifact for ERROR-state instances. See the Compute API error reference for a table of common fault messages and resolutions.

S3 XML error format#

The S3-compatible Object Storage interface (Swift with S3 middleware) returns errors as XML, following the AWS S3 error convention.

Standard format#

<Error>
  <Code>InvalidAccessKeyId</Code>
  <Message>The access key does not exist</Message>
  <RequestId>tx00000abc123def456-00661234-default</RequestId>
  <Resource>/my-bucket/my-key</Resource>
</Error>

Key fields#

Common S3 error codes#

Request correlation fields#

When an API error is not self-resolvable, collect these correlation fields before filing a support ticket. They allow support to trace your exact request through platform logs.

OpenStack APIs#

S3 interface#

Parsing errors in common tools#

curl + jq#

Read the error message from any OpenStack JSON error:

curl -s -w "\n%{http_code}" -H "X-Auth-Token: $OS_TOKEN" \
  "$OS_COMPUTE_URL/v2.1/servers/INVALID_ID" \
  | jq -r 'to_entries[0].value.message // "Unknown error"'

Python#

Parse the error from an openstacksdk or requests response:

import json

def parse_openstack_error(response):
    try:
        body = response.json()
        error_key = next(iter(body))
        return {
            "status": response.status_code,
            "message": body[error_key].get("message", "No message"),
            "request_id": response.headers.get("X-Openstack-Request-Id", ""),
        }
    except (json.JSONDecodeError, StopIteration):
        return {
            "status": response.status_code,
            "message": response.text[:200],
            "request_id": response.headers.get("X-Openstack-Request-Id", ""),
        }

S3 XML parsing (Python)#

import xml.etree.ElementTree as ET

def parse_s3_error(response):
    root = ET.fromstring(response.text)
    return {
        "code": root.findtext("Code", ""),
        "message": root.findtext("Message", ""),
        "request_id": root.findtext("RequestId", ""),
        "resource": root.findtext("Resource", ""),
    }

See also#

• Compute API error reference: HTTP status codes, fault messages, and resolutions
• Network API error reference: port, router, and security group errors
• Block storage API error reference: volume state machine and delete conflicts
• Object storage API error reference: S3 authentication and upload errors
• Retry and resilience patterns: which errors to retry and how
• API rate limits: quotas vs. rate limits, 429 handling
• Support ticket evidence collection: complete evidence checklist