How to do it...

1. Open your favorite text editor, and start a new CloudFormation template by defining the AWSTemplateFormatVersion and Description:

        AWSTemplateFormatVersion: "2010-09-09" 
        Description: Create an EFS file system and endpoints.

2. Create a top-level Parameters section, and define the required parameters, VpcId and SubnetIds, inside it:

        VpcId: 
          Description: VPC ID that contains the subnets that will 
            access the file system 
          Type: AWS::EC2::VPC::Id 
        SubnetIds: 
          Description: Subnet IDs allowed to access the EFS file system 
          Type: List<AWS::EC2::Subnet::Id>

3. Create a top-level Resources property, which will contain all the resources defined.

4. Under the Resources property, add the EFS filesystem resource:

        FileSystem: 
          Type: AWS::EFS::FileSystem 
          Properties: 
            FileSystemTags: 
              - Key: Name 
                Value: 
                  Fn::Sub: "${AWS::StackName} EFS File System" 
            PerformanceMode: generalPurpose

5. Add mount target resources for connecting to the filesystem you just created:

      MountTargetA: 
        Type: AWS::EFS::MountTarget 
        Properties: 
          FileSystemId: 
            Ref: FileSystem 
          SecurityGroups: 
            - Fn::GetAtt: MountTargetSecurityGroup.GroupId 
          SubnetId: 
            Fn::Select: [ 0, Ref: SubnetIds  ] 
      MountTargetB: 
        Type: AWS::EFS::MountTarget 
        Properties: 
          FileSystemId: 
            Ref: FileSystem 
          SecurityGroups: 
            - Fn::GetAtt: MountTargetSecurityGroup.GroupId 
          SubnetId: 
            Fn::Select: [ 1, Ref: SubnetIds  ]           

6. Create a security group to control access to the mount targets:

      MountTargetSecurityGroup: 
        Type: AWS::EC2::SecurityGroup 
        Properties: 
          GroupDescription: EFS endpoint security group 
          Tags: 
            - Key: Name 
              Value: MountTargetSecurityGroup 
          VpcId: 
            Ref: VpcId

7. Create a security group to access the mount target security group you created in the previous step:

      MountTargetAccessSecurityGroup: 
        Type: AWS::EC2::SecurityGroup 
        Properties: 
          GroupDescription: EFS endpoint access security group 
        Tags: 
          - Key: Name 
            Value: MountTargetAccessSecurityGroup 
        VpcId: 
          Ref: VpcId

8. Define the ingress and egress rules for the mount target security group:

      MountTargetIngress: 
        Type: AWS::EC2::SecurityGroupIngress 
        Properties: 
          FromPort: 2049 
          GroupId: 
            Fn::GetAtt: MountTargetSecurityGroup.GroupId 
          IpProtocol: tcp 
          SourceSecurityGroupId: 
            Fn::GetAtt: MountTargetAccessSecurityGroup.GroupId 
          ToPort: 2049 
      MountTargetEgress: 
        Type: AWS::EC2::SecurityGroupEgress 
        Properties: 
          DestinationSecurityGroupId: 
            Fn::GetAtt: MountTargetAccessSecurityGroup.GroupId 
          FromPort: 2049 
          GroupId: 
            Fn::GetAtt: MountTargetSecurityGroup.GroupId 
          IpProtocol: tcp 
          ToPort: 2049

9. Define the ingress and egress rules for the mount target access security group:

      MountTargetAccessIngress: 
        Type: AWS::EC2::SecurityGroupIngress 
        Properties: 
          FromPort: 22 
          GroupId: 
            Fn::GetAtt: MountTargetAccessSecurityGroup.GroupId 
          IpProtocol: tcp 
          CidrIp: 0.0.0.0/0 
          ToPort: 22 
      MountTargetAccessEgress: 
        Type: AWS::EC2::SecurityGroupEgress 
        Properties: 
          DestinationSecurityGroupId: 
            Fn::GetAtt: MountTargetSecurityGroup.GroupId 
          FromPort: 2049 
          GroupId: 
            Fn::GetAtt: MountTargetAccessSecurityGroup.GroupId 
          IpProtocol: tcp 
          ToPort: 2049

10. Save your template with the name 03-working-with-network-storage.yaml.
11. Launch the CloudFormation stack with the following AWS CLI command, substituting your own VPC ID and subnet IDs:

      aws cloudformation create-stack \
        --stack-name wwns1 \
        --template-body file://03-working-with-network-storage.yaml \
        --parameters \
        ParameterKey=VpcId,ParameterValue=<your-vpc-id> \  
        ParameterKey=SubnetIds,ParameterValue="<subnet-id-1>\, \
          <subnet-id-2>"