How do you attach an EFS file system to an EC2 instance?

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Accepted Answer

Mounting an EFS file system is similar to mounting any NFS share on Linux. AWS provides a helper utility called amazon-efs-utils that simplifies the process and adds features like automatic TLS encryption in transit and mount point recovery. The EFS DNS name automatically resolves to the Mount Target IP in the same Availability Zone as the EC2 instance, ensuring low-latency access. EFS file system must exist and have a Mount Target in the same AZ as your EC2 instance EC2 instance Security Group must allow outbound TCP port 2049 to the Mount Target Security Group Mount Target Security Group must allow inbound TCP port 2049 from the EC2 Security Group VPC must have DNS Resolution and DNS Hostnames enabled EC2 instance must be running Linux (EFS does not support Windows) amazon-efs-utils package must be installed on the EC2 instance for EFS mount helper # Amazon Linux 2 / Amazon Linux 2023
sudo yum install -y amazon-efs-utils

# Ubuntu / Debian
sudo apt-get update
sudo apt-get install -y amazon-efs-utils

# If amazon-efs-utils is not available, install NFS client instead
# Amazon Linux:
sudo yum install -y nfs-utils

# Ubuntu:
sudo apt-get install -y nfs-common # Create a mount point directory
sudo mkdir -p /mnt/efs

# Mount using EFS mount helper (fs-0abc... is your EFS File System ID)
# This automatically enables TLS encryption in transit
sudo mount -t efs fs-0abc1234567890def:/ /mnt/efs

# Mount with a specific Access Point
sudo mount -t efs \
  -o tls,accesspoint=fsap-0abc1234567890def \
  fs-0abc1234567890def:/ /mnt/efs

# Mount with explicit TLS option
sudo mount -t efs -o tls fs-0abc1234567890def:/ /mnt/efs

# Verify the mount
df -h
# Output: 127.0.0.1:/  8.0E  0  8.0E   0% /mnt/efs

# Test writing a file
sudo touch /mnt/efs/test-file.txt
ls /mnt/efs # Mount using the standard NFS client (no TLS)
sudo mount -t nfs4 \
  -o nfsvers=4.1,rsize=1048576,wsize=1048576,hard,timeo=600,retrans=2,noresvport \
  fs-0abc1234567890def.efs.us-east-1.amazonaws.com:/ \
  /mnt/efs # Add EFS mount to /etc/fstab for automatic remounting on reboot

# Using EFS mount helper (recommended)
echo 'fs-0abc1234567890def:/ /mnt/efs efs defaults,_netdev,tls 0 0' \
  | sudo tee -a /etc/fstab

# Using EFS mount helper with Access Point
echo 'fs-0abc1234567890def:/ /mnt/efs efs defaults,_netdev,tls,accesspoint=fsap-0abc 0 0' \
  | sudo tee -a /etc/fstab

# Using native NFS client
echo 'fs-0abc1234567890def.efs.us-east-1.amazonaws.com:/ /mnt/efs nfs4 nfsvers=4.1,rsize=1048576,wsize=1048576,hard,timeo=600,retrans=2,noresvport,_netdev 0 0' \
  | sudo tee -a /etc/fstab

# Test the fstab entry without rebooting
sudo umount /mnt/efs
sudo mount -a
df -h

# Important: The _netdev option ensures the OS waits for the
# network to be ready before attempting to mount EFS during boot #!/bin/bash
# Auto-mount EFS during instance launch via User Data

# Install EFS utils
yum install -y amazon-efs-utils

# Create mount directory
mkdir -p /mnt/shared

# Mount the EFS
mount -t efs -o tls fs-0abc1234567890def:/ /mnt/shared

# Persist across reboots
echo 'fs-0abc1234567890def:/ /mnt/shared efs defaults,_netdev,tls 0 0' >> /etc/fstab

echo 'EFS mounted successfully' >> /var/log/bootstrap.log

How do you attach an EFS file system to an EC2 instance?

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