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. For more information, see Amazon EFS: How it Works.
In the request, you also specify a file system ID for which you are creating the mount target and the file system's lifecycle state must be "available" (see DescribeFileSystems).
In the request, you also provide a subnet ID, which serves several purposes:
After creating the mount target, Amazon EFS returns a response that includes, a
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 via the mount target
can resolve the mount target's DNS name to its IP address. For more information, see
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 request to add another mount target must meet the following requirements:
The subnet specified in the request must belong to the same VPC as the subnets of the existing mount targets.
If the request satisfies the requirements, Amazon EFS does the following:
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
CreateNetworkInterfacecall does when a request does not specify a primary private IP address).
SecurityGroups, this network interface is associated with those security groups. Otherwise, it belongs to the default security group for the subnet's VPC.
"Mount target fsmt-id for file system fs-id"where
fsmt-idis the mount target ID, and
requesterManagedproperty of the network interface to "true", and the
requesterIdvalue to "EFS".
Each Amazon EFS mount target has one corresponding requestor-managed EC2 network interface.
After the network interface is created, Amazon EFS sets the
field in the mount target's description to the network interface ID, and the
field to its address. If network interface creation fails, the entire
CreateMountTargetcall 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 DescribeFileSystems API, which among other things returns the mount target state.
We recommend 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, go to Amazon EFS product detail page. In addition, by always using a mount target local to the instance's Availability Zone, you eliminate a partial failure scenario; if the Availablity Zone in which your mount target is created goes down, then you won't be able to access your file system through that mount target.
This operation requires permission for the following action on the file system:
This operation also requires permission for the following Amazon EC2 actions:
Version: (assembly version)
public abstract CreateMountTargetResponse CreateMountTarget( CreateMountTargetRequest request )
Container for the necessary parameters to execute the CreateMountTarget service method.
|BadRequestException||Returned if the request is malformed or contains an error such as an invalid parameter value or a missing required parameter.|
|FileSystemNotFoundException||Returned if the specified FileSystemId does not exist in the requester's AWS account.|
|IncorrectFileSystemLifeCycleStateException||Returned if the file system's life cycle state is not "created".|
|InternalServerErrorException||Returned if an error occurred on the server side.|
|IpAddressInUseException||Returned if the request specified an IpAddress that is already in use in the subnet.|
|MountTargetConflictException||Returned if the mount target would violate one of the specified restrictions based on the file system's existing mount targets.|
|NetworkInterfaceLimitExceededException||The calling account has reached the ENI limit for the specific AWS region. Client should try to delete some ENIs or get its account limit raised. For more information, go to Amazon VPC Limits in the Amazon Virtual Private Cloud User Guide (see the Network interfaces per VPC entry in the table).|
|NoFreeAddressesInSubnetException||Returned if IpAddress was not specified in the request and there are no free IP addresses in the subnet.|
|SecurityGroupLimitExceededException||Returned if the size of SecurityGroups specified in the request is greater than five.|
|SecurityGroupNotFoundException||Returned if one of the specified security groups does not exist in the subnet's VPC.|
|SubnetNotFoundException||Returned if there is no subnet with ID SubnetId provided in the request.|
Supported in: 4.5, 4.0, 3.5