CreateMountTarget - Amazon Elastic File System

CreateMountTarget

Creates a mount target for a file system. You can then mount the file system on EC2 instances by using the mount target.

You can create one mount target in each Availability Zone in your VPC. All EC2 instances in a VPC within a given Availability Zone share a single mount target for a given file system. If you have multiple subnets in an Availability Zone, you create a mount target in one of the subnets. EC2 instances do not need to be in the same subnet as the mount target in order to access their file system.

You can create only one mount target for a One Zone file system. You must create that mount target in the same Availability Zone in which the file system is located. Use the AvailabilityZoneName and AvailabiltyZoneId properties in the DescribeFileSystems response object to get this information. Use the subnetId associated with the file system's Availability Zone when creating the mount target.

For more information, see Amazon EFS: How it Works.

To create a mount target for a file system, the file system's lifecycle state must be available. For more information, see DescribeFileSystems.

In the request, provide the following:

  • The file system ID for which you are creating the mount target.

  • A subnet ID, which determines the following:

    • The VPC in which Amazon EFS creates the mount target

    • The Availability Zone in which Amazon EFS creates the mount target

    • The IP address range from which Amazon EFS selects the IP address of the mount target (if you don't specify an IP address in the request)

After creating the mount target, Amazon EFS returns a response that includes, a MountTargetId and an IpAddress. You use this IP address when mounting the file system in an EC2 instance. You can also use the mount target's DNS name when mounting the file system. The EC2 instance on which you mount the file system by using the mount target can resolve the mount target's DNS name to its IP address. For more information, see How it Works: Implementation Overview.

Note that you can create mount targets for a file system in only one VPC, and there can be only one mount target per Availability Zone. That is, if the file system already has one or more mount targets created for it, the subnet specified in the request to add another mount target must meet the following requirements:

  • Must belong to the same VPC as the subnets of the existing mount targets

  • Must not be in the same Availability Zone as any of the subnets of the existing mount targets

If the request satisfies the requirements, Amazon EFS does the following:

  • Creates a new mount target in the specified subnet.

  • Also creates a new network interface in the subnet as follows:

    • If the request provides an IpAddress, Amazon EFS assigns that IP address to the network interface. Otherwise, Amazon EFS assigns a free address in the subnet (in the same way that the Amazon EC2 CreateNetworkInterface call does when a request does not specify a primary private IP address).

    • If the request provides SecurityGroups, this network interface is associated with those security groups. Otherwise, it belongs to the default security group for the subnet's VPC.

    • Assigns the description Mount target fsmt-id for file system fs-id where fsmt-id is the mount target ID, and fs-id is the FileSystemId.

    • Sets the requesterManaged property of the network interface to true, and the requesterId value to EFS.

    Each Amazon EFS mount target has one corresponding requester-managed EC2 network interface. After the network interface is created, Amazon EFS sets the NetworkInterfaceId field in the mount target's description to the network interface ID, and the IpAddress field to its address. If network interface creation fails, the entire CreateMountTarget operation fails.

Note

The CreateMountTarget call returns only after creating the network interface, but while the mount target state is still creating, you can check the mount target creation status by calling the DescribeMountTargets operation, which among other things returns the mount target state.

We recommend that you create a mount target in each of the Availability Zones. There are cost considerations for using a file system in an Availability Zone through a mount target created in another Availability Zone. For more information, see Amazon EFS. In addition, by always using a mount target local to the instance's Availability Zone, you eliminate a partial failure scenario. If the Availability Zone in which your mount target is created goes down, then you can't access your file system through that mount target.

This operation requires permissions for the following action on the file system:

  • elasticfilesystem:CreateMountTarget

This operation also requires permissions for the following Amazon EC2 actions:

  • ec2:DescribeSubnets

  • ec2:DescribeNetworkInterfaces

  • ec2:CreateNetworkInterface

Request Syntax

POST /2015-02-01/mount-targets HTTP/1.1 Content-type: application/json { "FileSystemId": "string", "IpAddress": "string", "SecurityGroups": [ "string" ], "SubnetId": "string" }

URI Request Parameters

The request does not use any URI parameters.

Request Body

The request accepts the following data in JSON format.

FileSystemId

The ID of the file system for which to create the mount target.

Type: String

Length Constraints: Maximum length of 128.

Pattern: ^(arn:aws[-a-z]*:elasticfilesystem:[0-9a-z-:]+:file-system/fs-[0-9a-f]{8,40}|fs-[0-9a-f]{8,40})$

Required: Yes

IpAddress

Valid IPv4 address within the address range of the specified subnet.

Type: String

Length Constraints: Minimum length of 7. Maximum length of 15.

Pattern: ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$

Required: No

SecurityGroups

Up to five VPC security group IDs, of the form sg-xxxxxxxx. These must be for the same VPC as subnet specified.

Type: Array of strings

Array Members: Maximum number of 100 items.

Length Constraints: Minimum length of 11. Maximum length of 43.

Pattern: ^sg-[0-9a-f]{8,40}

Required: No

SubnetId

The ID of the subnet to add the mount target in. For One Zone file systems, use the subnet that is associated with the file system's Availability Zone.

Type: String

Length Constraints: Minimum length of 15. Maximum length of 47.

Pattern: ^subnet-[0-9a-f]{8,40}$

Required: Yes

Response Syntax

HTTP/1.1 200 Content-type: application/json { "AvailabilityZoneId": "string", "AvailabilityZoneName": "string", "FileSystemId": "string", "IpAddress": "string", "LifeCycleState": "string", "MountTargetId": "string", "NetworkInterfaceId": "string", "OwnerId": "string", "SubnetId": "string", "VpcId": "string" }

Response Elements

If the action is successful, the service sends back an HTTP 200 response.

The following data is returned in JSON format by the service.

AvailabilityZoneId

The unique and consistent identifier of the Availability Zone that the mount target resides in. For example, use1-az1 is an AZ ID for the us-east-1 Region and it has the same location in every AWS account.

Type: String

AvailabilityZoneName

The name of the Availability Zone in which the mount target is located. Availability Zones are independently mapped to names for each AWS account. For example, the Availability Zone us-east-1a for your AWS account might not be the same location as us-east-1a for another AWS account.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 64.

Pattern: .+

FileSystemId

The ID of the file system for which the mount target is intended.

Type: String

Length Constraints: Maximum length of 128.

Pattern: ^(arn:aws[-a-z]*:elasticfilesystem:[0-9a-z-:]+:file-system/fs-[0-9a-f]{8,40}|fs-[0-9a-f]{8,40})$

IpAddress

Address at which the file system can be mounted by using the mount target.

Type: String

Length Constraints: Minimum length of 7. Maximum length of 15.

Pattern: ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$

LifeCycleState

Lifecycle state of the mount target.

Type: String

Valid Values: creating | available | updating | deleting | deleted | error

MountTargetId

System-assigned mount target ID.

Type: String

Length Constraints: Minimum length of 13. Maximum length of 45.

Pattern: ^fsmt-[0-9a-f]{8,40}$

NetworkInterfaceId

The ID of the network interface that Amazon EFS created when it created the mount target.

Type: String

OwnerId

AWS account ID that owns the resource.

Type: String

Length Constraints: Maximum length of 14.

Pattern: ^(\d{12})|(\d{4}-\d{4}-\d{4})$

SubnetId

The ID of the mount target's subnet.

Type: String

Length Constraints: Minimum length of 15. Maximum length of 47.

Pattern: ^subnet-[0-9a-f]{8,40}$

VpcId

The virtual private cloud (VPC) ID that the mount target is configured in.

Type: String

Errors

AvailabilityZonesMismatch

Returned if the Availability Zone that was specified for a mount target is different from the Availability Zone that was specified for One Zone storage. For more information, see Regional and One Zone storage redundancy.

HTTP Status Code: 400

BadRequest

Returned if the request is malformed or contains an error such as an invalid parameter value or a missing required parameter.

HTTP Status Code: 400

FileSystemNotFound

Returned if the specified FileSystemId value doesn't exist in the requester's AWS account.

HTTP Status Code: 404

IncorrectFileSystemLifeCycleState

Returned if the file system's lifecycle state is not "available".

HTTP Status Code: 409

InternalServerError

Returned if an error occurred on the server side.

HTTP Status Code: 500

IpAddressInUse

Returned if the request specified an IpAddress that is already in use in the subnet.

HTTP Status Code: 409

MountTargetConflict

Returned if the mount target would violate one of the specified restrictions based on the file system's existing mount targets.

HTTP Status Code: 409

NetworkInterfaceLimitExceeded

The calling account has reached the limit for elastic network interfaces for the specific AWS Region. Either delete some network interfaces or request that the account quota be raised. For more information, see Amazon VPC Quotas in the Amazon VPC User Guide (see the Network interfaces per Region entry in the Network interfaces table).

HTTP Status Code: 409

NoFreeAddressesInSubnet

Returned if IpAddress was not specified in the request and there are no free IP addresses in the subnet.

HTTP Status Code: 409

SecurityGroupLimitExceeded

Returned if the size of SecurityGroups specified in the request is greater than five.

HTTP Status Code: 400

SecurityGroupNotFound

Returned if one of the specified security groups doesn't exist in the subnet's virtual private cloud (VPC).

HTTP Status Code: 400

SubnetNotFound

Returned if there is no subnet with ID SubnetId provided in the request.

HTTP Status Code: 400

UnsupportedAvailabilityZone

Returned if the requested Amazon EFS functionality is not available in the specified Availability Zone.

HTTP Status Code: 400

Examples

Add a mount target to a file system

The following request creates a mount target for a file system. The request specifies values for only the required FileSystemId and SubnetId parameters. The request does not provide the optional IpAddress and SecurityGroups parameters. For IpAddress, the operation uses one of the available IP addresses in the specified subnet. And, the operation uses the default security group associated with the VPC for the SecurityGroups.

Sample Request

POST /2015-02-01/mount-targets HTTP/1.1 Host: elasticfilesystem.us-west-2.amazonaws.com x-amz-date: 20140620T221118Z Authorization: <...> Content-Type: application/json Content-Length: 160 {"SubnetId": "subnet-748c5d03", "FileSystemId": "fs-01234567"}

Sample Response

HTTP/1.1 200 OK x-amzn-RequestId: 01234567-89ab-cdef-0123-456789abcdef Content-Type: application/json Content-Length: 252 { "MountTargetId": "fsmt-55a4413c", "NetworkInterfaceId": "eni-01234567", "FileSystemId": "fs-01234567", "LifeCycleState": "available", "SubnetId": "subnet-01234567", "OwnerId": "231243201240", "IpAddress": "172.31.22.183" }

Add a mount target to a file system

The following request specifies all the request parameters to create a mount target.

Sample Request

POST /2015-02-01/mount-targets HTTP/1.1 Host: elasticfilesystem.us-west-2.amazonaws.com x-amz-date: 20140620T221118Z Authorization: <...> Content-Type: application/json Content-Length: 160 { "FileSystemId":"fs-01234567", "SubnetId":"subnet-01234567", "IpAddress":"10.0.2.42", "SecurityGroups":[ "sg-01234567" ] }

Sample Response

HTTP/1.1 200 OK x-amzn-RequestId: 01234567-89ab-cdef-0123-456789abcdef Content-Type: application/json Content-Length: 252 { "OwnerId":"251839141158", "MountTargetId":"fsmt-9a13661e", "FileSystemId":"fs-01234567", "SubnetId":"subnet-fd04ff94", "LifeCycleState":"available", "IpAddress":"10.0.2.42", "NetworkInterfaceId":"eni-1bcb7772" }

See Also

For more information about using this API in one of the language-specific AWS SDKs, see the following: