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E-MapReduce:ListComponents

Last Updated:Aug 28, 2026

Retrieves a list of components.

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RAM authorization

The table below describes the authorization required to call this API. You can define it in a Resource Access Management (RAM) policy. The table's columns are detailed below:

  • Action: The actions can be used in the Action element of RAM permission policy statements to grant permissions to perform the operation.

  • API: The API that you can call to perform the action.

  • Access level: The predefined level of access granted for each API. Valid values: create, list, get, update, and delete.

  • Resource type: The type of the resource that supports authorization to perform the action. It indicates if the action supports resource-level permission. The specified resource must be compatible with the action. Otherwise, the policy will be ineffective.

    • For APIs with resource-level permissions, required resource types are marked with an asterisk (*). Specify the corresponding Alibaba Cloud Resource Name (ARN) in the Resource element of the policy.

    • For APIs without resource-level permissions, it is shown as All Resources. Use an asterisk (*) in the Resource element of the policy.

  • Condition key: The condition keys defined by the service. The key allows for granular control, applying to either actions alone or actions associated with specific resources. In addition to service-specific condition keys, Alibaba Cloud provides a set of common condition keys applicable across all RAM-supported services.

  • Dependent action: The dependent actions required to run the action. To complete the action, the RAM user or the RAM role must have the permissions to perform all dependent actions.

Action

Access level

Resource type

Condition key

Dependent action

emr:ListComponents

list

*All Resource

*

None None

Request parameters

Parameter

Type

Required

Description

Example

RegionId

string

Yes

The region ID. You can call the ListRegions operation to query available region IDs.

cn-hangzhou

ClusterId

string

Yes

The cluster ID.

C-8CFEBCCFFEF5****

NextToken

string

No

The pagination token used in the next request to retrieve a new page of results. Leave this parameter empty to query from the beginning.

""

MaxResults

integer

No

The number of entries to return on each page.

10

ApplicationNames

array

No

The application name.

20

string

No

The application name.

KNOX

ComponentNames

array

No

The list of component names.

["HDFS"]

string

No

The component name.

KNOX

ComponentStates

array

No

The list of component states.

null

string

No

The status of the component.

INSTALLED

Response elements

Element

Type

Description

Example

object

The response parameters.

Components

array<object>

The list of component information.

object

The component information.

ComponentName

string

The component name.

KNOX

ApplicationName

string

The application name.

KNOX

Replica

integer

The total number of instances on which the component is installed.

1

Namespace

string

The reserved field.

“”

Attributes

array

The list of attributes.

Attribute

The name of the attribute.

RequestId

string

The request ID.

FFAC608A-5DC3-174F-93C6-9F88CA6D5875

NextToken

string

A pagination token used to retrieve a new page of results.

DD6B1B2A-5837-5237-ABE4-FF0C89568980

MaxResults

integer

The maximum number of entries returned.

20

TotalCount

integer

The total number of entries returned.

200

Examples

Success response

JSON format

{
  "Components": [
    {
      "ComponentName": "KNOX",
      "ApplicationName": "KNOX",
      "Replica": 1,
      "Namespace": "“”",
      "Attributes": [
        {
          "Key": "currentYarnRangerPluginState",
          "Value": "true"
        }
      ]
    }
  ],
  "RequestId": "FFAC608A-5DC3-174F-93C6-9F88CA6D5875",
  "NextToken": "DD6B1B2A-5837-5237-ABE4-FF0C89568980",
  "MaxResults": 20,
  "TotalCount": 200
}

Error codes

HTTP status code

Error code

Error message

Description

400 ConflictParameters Parameters that must not be used together. %s
400 IncompleteSignature The request signature is invalid.
400 InvalidAction The action %s requested is invalid.
400 InvalidParameter The specified parameter %s is not valid.
400 InvalidParameterValue The input parameter %s is invalid or out of range.
400 MissingAction The action %s requested is missing.
400 MissingParameter The input parameter %s that is mandatory for processing this request is not supplied.
400 NotAuthorized You do not have permission to perform this action. %s
400 ThrottlingException The request was denied due to request throttling. %s
500 InternalError The request processing has failed due to some unknown error, exception or failure.
404 ResourceNotFound The resource not found by %s.
503 ServiceFailure The request has failed due to a temporary failure of %s service.
503 ServiceUnavailable The request has failed due to a temporary failure of the server.

See Error Codes for a complete list.

Release notes

See Release Notes for a complete list.