Amazon ECS with Persistent Data Volumes (EFS) | Overview.

Amazon ECS  with Persistent Data Volumes (EFS) - Overview.

Scope:

• Intro,
• Amazon ECS – Data Volumes Overview,
• Why Uses EFS with ECS,
• ECS Volume Types (Summary)
• Architecture of  ECS + EFS (Fargate or EC2),
• Setting Up ECS with EFS,
• Terraform sample Snippet – ECS Task with EFS (code),
• Use Cases for EFS in ECS,
• Best Practices.

Intro

• Here’s twtech overview of using data volumes with Amazon ECS, focusing on Amazon EFS (Elastic File System) Persistent integration.

 Amazon ECS – Data Volumes Overview

• In ECS, volumes are used to persist data across container restarts and share data between containers. 
• The most durable and scalable way to do this is using Amazon EFS, a fully managed network file system.

 Why twtech Uses EFS with ECS

Benefit	Description
Persistent storage.	Data survives task restarts or replacements
Shared storage.	Multiple ECS tasks can access the same files
Scalable & managed.	Grows automatically, no provisioning
POSIX compliant.	Works like a Linux file system
Multi-AZ support.	High availability and durability

 ECS Volume Types (Summary)

Volume Type	Description	Scope
Ephemeral.	Lives only during task lifetime	Task-local
Bind Mount.	Host-path mount (EC2-only)	ECS-EC2 only
EFS Volume.	Durable, shared, elastic	Fargate & EC2

 Architecture of  ECS + EFS (Fargate or EC2)

 Setting Up ECS with EFS

Step 1: Create an EFS File System

• Via AWS Console or CLI
• Enable access points (optional, recommended for task isolation)
• Choose VPC and mount targets in each subnet

Step 2: Create ECS Task Definition with EFS Volume

Sample JSON snippet:

# json 

{

  "volumes": [

    {

      "name": "twtech-efs-volume",

      "efsVolumeConfiguration": {

        "fileSystemId": "fs-12345xxx",

        "rootDirectory": "/twtech-app",

        "transitEncryption": "ENABLED"

      }

    }

  ],

  "containerDefinitions": [

    {

      "name": "twtechwebapp",

      "image": "twtech-web-app:latest",

      "mountPoints": [

        {

          "sourceVolume": "twtech-efs-volume",

          "containerPath": "/mnt/data"

        }

      ]

    }

  ]

}

 NB:

• TransitEncryption is Set to:  "ENABLED" for encrypted connections

Step 3: Networking Configuration

• Ensure ECS tasks are in the same VPC as the EFS mount targets
• Security groups:
• EFS SG must allow NFS (port 2049) from ECS tasks
• ECS SG should be attached to task ENIs

✅ Fargate + EFS Support

Yes.

•  Since 2020, Fargate supports mounting EFS volumes.

Requirements:

• Use awsvpc network mode (default for Fargate)
• Define volume in efsVolumeConfiguration
• No need for mounting tools — AWS manages it

 Terraform sample Snippet – ECS Task with EFS (code)

# hcl

resource "aws_ecs_task_definition" "twtech-efs-task" {

  family                   = "twtech-efs-task"

  requires_compatibilities = ["FARGATE"]

  network_mode            = "awsvpc"

  cpu                     = "256"

  memory                  = "512"

  execution_role_arn      = aws_iam_role.ecs_execution.arn

  task_role_arn           = aws_iam_role.ecs_task.arn

  volume {

    name = "twtech-efs-storage"

    efs_volume_configuration {

      file_system_id     = aws_efs_file_system.twtech.id

      transit_encryption = "ENABLED"

    }

  }

  container_definitions = jsonencode([

    {

      name      = "twtechwebapp"

      image     = "twtech-web-app"

      essential = true

      mountPoints = [

        {

          sourceVolume  = "twtech-efs-storage"

          containerPath = "/mnt/data"

        }

      ]

    }

  ])

}

 

twtech Use Cases for EFS in ECS

Use Case	Why EFS is Ideal
Web servers (e.g., twtech-web-app).	Serve shared content from EFS
Content management systems.	Persistent storage for uploaded media
Machine learning models.	Share large model files across tasks
Logs and archives.	Keep logs even after task shutdown
File-based state sharing.	Share state across multiple containers

twtech Best Practices

• Use Access Points for task-level file system isolation
• Enable encryption in transit and at rest
• Monitor usage with Amazon CloudWatch + AWS CloudTrail
• Avoid storing millions of tiny files — EFS is better for large files or directories.