CreateSession - Function Compute - Alibaba Cloud Documentation Center

Creates an explicit session resource by automatically generating a unique session ID, pre-allocating a function instance, and attaching the session. This operation supports custom Time to Live (TTL) and idle timeout values, applies to HEADER_FIELD or GENERATED_COOKIE affinity types, and is used for session prefetching and configuration initialization. After the session is created, include the session ID in InvokeFunction requests for request routing.

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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

fc:CreateSession

create

*All Resource

*

None

Request syntax

POST /2023-03-30/functions/{functionName}/sessions HTTP/1.1

Path Parameters

Parameter	Type	Required	Description	Example
functionName	string	No	The name of the function for which the session is created.	my-func

Request parameters

Parameter	Type	Required	Description	Example
qualifier	string	No	The version or alias to which the session belongs.	aliasName1
body	CreateSessionInput	No	The configuration of the session.

Response elements

Element	Type	Description	Example
	Session	The information about the session resource.

Examples

Success response

JSON format

{
  "sessionId": "81f70ae156904eb9b7d43e12f511fe58",
  "functionName": "functionName1",
  "sessionAffinityType": "HEADER_FIELD",
  "sessionTTLInSeconds": 21600,
  "sessionIdleTimeoutInSeconds": 1800,
  "createdTime": "2025-04-01T08:15:27Z",
  "lastModifiedTime": "2025-04-01T18:15:27Z",
  "sessionStatus": "Active",
  "containerId": "c-68999e02-16a1955c-d2a03d1ccs",
  "qualifier": "AliasName1",
  "nasConfig": {
    "groupId": 100,
    "mountPoints": [
      {
        "enableTLS": true,
        "mountDir": "/home/test",
        "serverAddr": "***-uni85.cn-hangzhou.nas.com:/"
      }
    ],
    "userId": 100
  },
  "disableSessionIdReuse": false
}

Error codes

See Error Codes for a complete list.

Release notes

See Release Notes for a complete list.