Capacity provider system log format
Capacity provider system logs use structured JSON format. JSON structured logs provide enhanced searchability and enable automated analysis of your capacity provider operational events.
JSON format for system logs
Each system log entry is captured as a JSON object that contains key-value pairs with the following top-level fields:
| Field | Type | Description |
|---|---|---|
timestamp |
String | The time the log event was generated, in ISO 8601 format. |
level |
String | The log level of the event. |
message |
String | A human-readable description of the event. |
metadata |
Object | Structured metadata about the event. Contains fields that vary by event type. |
Metadata fields
The metadata object contains the following fields. Not all fields are present in every event.
| Field | Type | Description |
|---|---|---|
instanceId |
String | The Amazon EC2 instance ID associated with the event. |
availabilityZones |
Array of strings | The Availability Zone(s) associated with the event. |
instanceTypes |
Array of strings | The Amazon EC2 instance type(s) associated with the event. |
capacityProviderArn |
String | The ARN of the capacity provider. |
Example log entry
The following example shows a system log entry for a successful instance launch:
{
"timestamp": "2025-07-01T14:31:15.456Z",
"level": "INFO",
"message": "Successfully launched c7g.xlarge instance i-0abc123def456789 in us-east-1a",
"metadata": {
"instanceId": "i-0abc123def456789",
"availabilityZones": ["us-east-1a"],
"instanceTypes": ["c7g.xlarge"],
"capacityProviderArn": "arn:aws:lambda:us-east-1:123456789012:capacity-provider:my-capacity-provider"
}
}