The github repository for this project is here!.

Using AWS CDK we can quickly deploy a small EC2 Instance to act as an FTP Server with an unlimited S3 storage backend.

With an hourly rate of only $0.0058 (us-east-1), t2-nano is sufficient for running a small FTP server with the S3 integration!

The server is configured on deploy using EC2 UserData. mount-s3 is used for mounting an S3 bucket to your instance. We start up VSFTPD, set up a virtual user in the same directory as our mounted S3 bucket, and we have our end-to-end FTP solution!

1. A user connects to the instance with the instance's Public IP or DNS.
2. The user agrees to use the server's TLS certificate.
3. A secure FTPS connection is made and the user can freely work with the files on the S3 bucket.

You'll find the code for the stack in lib/ftp-server-stack.ts. It uses four custom Constructs:

1. VPCStuff creates a simple VPC with no NAT Gateways since they aren't necessary and we want to save on cost (NAT Gateways are expensive!)
2. StorageStuff creates a bucket to persist data from the FTP server. It's set to automatically delete data and remove itself on cdk destroy.
3. SecurityStuff creates an IAM Role with permissions to read and write to the FTP bucket and access the Secret that stores the password for the ftpUser account we will create on the EC2 instance. SecurityStuff also creates an EC2 Security Group inside our VPC which allows SSH and FTP access into the EC2 instance. Additionally, we open ports which will be used for the data connection with VSFTPD
4. Finally, ec2InstanceStuff creates and configures the EC2 instance. The instance is based on Amazon Linux 2

The EC2 instance Public IP and the FTP Bucket name gets output upon successful deploy.

AWS CDK is used to synthesize the CloudFormation template that will deploy our architecture and also configure the server. We configure the EC2 instance using EC2 UserData stored as a bash script in lib/ec2-setup.sh. We also use CloudFormationInit to store a slightly customized vsftpd.conf file.

1. Make a secret on AWS Secrets Manager for your ftp user password. You'll use this when connecting to the server.
2. Fix references to your secret. I named by secret "ftpUser_Password". You'll find references to this in the ec2InstanceStuff and securityStuff constructs in lib/ftp-server-stack.ts
3. Create a Key Pair using the AWS EC2 Console. You'll need this to access the instance by SSH.
4. Fix references to the Key Pair. I've named mine "RiceCooker_FTP_Server" - this needs to match the Key Pair that you just made.
5. Copy the repo and cdk deploy!

In researching this solution I ran into many different ways people were trying to make an affordable FTP server. Some used ECS, others were deploying docker containers onto an EC2 instance (main inspiration). I found them all to be overly complex, and I always prefer a repeatable approach using CDK.

I hope you found this useful - let me know!