# Retry Policy for Pipeline Steps
<a name="pipelines-retry-policy"></a>

Retry policies help you automatically retry your Pipelines steps after an error occurs. Any pipeline step can encounter exceptions, and exceptions happen for various reasons. In some cases, a retry can resolve these issues. With a retry policy for pipeline steps, you can choose whether to retry a particular pipeline step or not.

The retry policy only supports the following pipeline steps:
+ [Processing step](build-and-manage-steps-types.md#step-type-processing) 
+ [Training step](build-and-manage-steps-types.md#step-type-training) 
+ [Tuning step](build-and-manage-steps-types.md#step-type-tuning) 
+ [AutoML step](build-and-manage-steps-types.md#step-type-automl) 
+ [Create model step](build-and-manage-steps-types.md#step-type-create-model) 
+ [Register model step](build-and-manage-steps-types.md#step-type-register-model) 
+ [Transform step](build-and-manage-steps-types.md#step-type-transform) 
+ [Notebook job step](build-and-manage-steps-types.md#step-type-notebook-job) 

**Note**  
Jobs running inside both the tuning and AutoML steps conduct retries internally and will not retry the `SageMaker.JOB_INTERNAL_ERROR` exception type, even if a retry policy is configured. You can program your own [ Retry Strategy](https://docs.amazonaws.cn/sagemaker/latest/APIReference/API_RetryStrategy.html) using the SageMaker API.

## Supported exception types for the retry policy
<a name="pipelines-retry-policy-supported-exceptions"></a>

The retry policy for pipeline steps supports the following exception types:
+ `Step.SERVICE_FAULT`: These exceptions occur when an internal server error or transient error happens when calling downstream services. Pipelines retries on this type of error automatically. With a retry policy, you can override the default retry operation for this exception type.
+ `Step.THROTTLING`: Throttling exceptions can occur while calling the downstream services. Pipelines retries on this type of error automatically. With a retry policy, you can override the default retry operation for this exception type.
+ `SageMaker.JOB_INTERNAL_ERROR`: These exceptions occur when the SageMaker AI job returns `InternalServerError`. In this case, starting a new job may fix a transient issue.
+ `SageMaker.CAPACITY_ERROR`: The SageMaker AI job may encounter Amazon EC2 `InsufficientCapacityErrors`, which leads to the SageMaker AI job’s failure. You can retry by starting a new SageMaker AI job to avoid the issue. 
+ `SageMaker.RESOURCE_LIMIT`: You can exceeed the resource limit quota when running a SageMaker AI job. You can wait and retry running the SageMaker AI job after a short period and see if resources are released.

## The JSON schema for the retry policy
<a name="pipelines-retry-policy-json-schema"></a>

The retry policy for Pipelines has the following JSON schema:

```
"RetryPolicy": {
   "ExceptionType": [String]
   "IntervalSeconds": Integer
   "BackoffRate": Double
   "MaxAttempts": Integer
   "ExpireAfterMin": Integer
}
```
+ `ExceptionType`: This field requires the following exception types in a string array format.
  + `Step.SERVICE_FAULT`
  + `Step.THROTTLING`
  + `SageMaker.JOB_INTERNAL_ERROR`
  + `SageMaker.CAPACITY_ERROR`
  + `SageMaker.RESOURCE_LIMIT`
+ `IntervalSeconds` (optional): The number of seconds before the first retry attempt (1 by default). `IntervalSeconds` has a maximum value of 43200 seconds (12 hours).
+ `BackoffRate` (optional): The multiplier by which the retry interval increases during each attempt (2.0 by default).
+ `MaxAttempts` (optional): A positive integer that represents the maximum number of retry attempts (5 by default). If the error recurs more times than `MaxAttempts` specifies, retries cease and normal error handling resumes. A value of 0 specifies that errors are never retried. `MaxAttempts` has a maximum value of 20.
+ `ExpireAfterMin` (optional): A positive integer that represents the maximum timespan of retry. If the error recurs after `ExpireAfterMin` minutes counting from the step gets executed, retries cease and normal error handling resumes. A value of 0 specifies that errors are never retried. `ExpireAfterMin ` has a maximum value of 14,400 minutes (10 days).
**Note**  
Only one of `MaxAttempts` or `ExpireAfterMin` can be given, but not both; if both are *not* specified, `MaxAttempts` becomes the default. If both properties are identified within one policy, then the retry policy generates a validation error.