EFS Creation Fails

Serverless Framework
7

Found it! So before I got this error:

 Serverless Error ----------------------------------------
 
  An error occurred: MyFunctionLambdaFunction - EFS file system arn:aws:elasticfilesystem:eu-west-1:<account-id>:file-system/<fs-code> referenced by access point arn:aws:elasticfilesystem:eu-west-1:<account-id>:access-point/<fsap-code> has mount targets created in all availability zones the function will execute in, but not all are in the available life cycle state yet. Please wait for them to become available and try the request again. (Service: AWSLambdaInternal; Status Code: 400; Error Code: InvalidParameterValueException; Request ID: 5dd189ac-b6a9-42ef-a8e6-7dba88019d12; Proxy: null).

I got it working by adding an additional DependsOn attribute on the AccessPoint as suggested here. The serverless yaml then looks something like this:

frameworkVersion: '2'

provider:
  name: aws
  stage: ${opt:stage, 'dev'}
  region: eu-west-1
  lambdaHashingVersion: 20201221

functions:
  myFunction:
    handler: some_handler
    fileSystemConfig:
      localMountPath: /mnt/efs
      arn: !GetAtt AccessPoint.Arn
    vpc:
      securityGroupIds:
        - !GetAtt Vpc.DefaultSecurityGroup
      subnetIds:
        - !Ref SubnetA
        - !Ref SubnetB
        - !Ref SubnetC

resources:
  Resources:
    Vpc:
      Type: AWS::EC2::VPC
      Properties:
        CidrBlock: 172.31.0.0/16
        EnableDnsHostnames: True
        EnableDnsSupport: True
    SubnetA:
      Type: AWS::EC2::Subnet
      Properties:
        CidrBlock: 172.31.1.0/24
        VpcId: !Ref Vpc
        AvailabilityZone: "${self:provider.region}a"
    SubnetB:
      Type: AWS::EC2::Subnet
      Properties:
        CidrBlock: 172.31.2.0/24
        VpcId: !Ref Vpc
        AvailabilityZone: "${self:provider.region}b"
    SubnetC:
      Type: AWS::EC2::Subnet
      Properties:
        CidrBlock: 172.31.3.0/24
        VpcId: !Ref Vpc
        AvailabilityZone: "${self:provider.region}c"
    ElasticFileSystem:
      Type: AWS::EFS::FileSystem
      Properties:
        Encrypted: true
        PerformanceMode: generalPurpose
        FileSystemPolicy:
          Version: "2012-10-17"
          Statement:
            - Effect: "Allow"
              Action:
                - "elasticfilesystem:ClientMount"
                - "elasticfilesystem:ClientWrite"
              Principal:
                AWS: "*"
    AccessPoint:
      Type: AWS::EFS::AccessPoint
      Properties:
        FileSystemId: !Ref ElasticFileSystem
        PosixUser:
          Uid: "1000"
          Gid: "1000"
        RootDirectory:
          CreationInfo:
            OwnerGid: "1000"
            OwnerUid: "1000"
            Permissions: "0777"
          Path: "/my-data"
      DependsOn:
        - MountTargetA
        - MountTargetB
        - MountTargetC
    MountTargetA:
      Type: AWS::EFS::MountTarget
      Properties:
        FileSystemId: !Ref ElasticFileSystem
        SecurityGroups:
          - !GetAtt Vpc.DefaultSecurityGroup
        SubnetId: !Ref SubnetA
    MountTargetB:
      Type: AWS::EFS::MountTarget
      Properties:
        FileSystemId: !Ref ElasticFileSystem
        SecurityGroups:
          - !GetAtt Vpc.DefaultSecurityGroup
        SubnetId: !Ref SubnetB
    MountTargetC:
      Type: AWS::EFS::MountTarget
      Properties:
        FileSystemId: !Ref ElasticFileSystem
        SecurityGroups:
          - !GetAtt Vpc.DefaultSecurityGroup
        SubnetId: !Ref SubnetC