AWS Storage EFS Demo

In this lesson, we demonstrate how to deploy and use AWS Elastic File System (EFS), highlighting its benefits such as mounting the same file system on multiple EC2 instances. This guide complements our previous Elastic Block Store demo by focusing on a shared file system accessible by multiple machines.

Overview

This demo uses two EC2 instances running in the US East 1C Availability Zone. Our objective is to create an EFS file system and mount it on both instances. One of the key advantages of EFS is its ability to allow concurrent access by multiple instances.

First, verify that your EC2 instances (instance one and instance two) are up and running in US East 1C. Once confirmed, proceed with creating the Elastic File System.

Creating the EFS File System

1. In the AWS Management Console, search for the Elastic File System service.

2. Click Create File System. You can choose the default quick creation option or select Customize to adjust detailed settings:

   • Provide a name (e.g., "EFS Demo").
   • Choose the storage class:
     • Standard: Ensures redundancy across multiple Availability Zones.
     • One Zone: Stores the file system in a single Availability Zone.

   

3. For this demonstration, disable automatic backups, choose lifecycle settings as needed, and leave encryption disabled. Use the default throughput mode.

4. Click Next.

Configuring Mount Targets

Mount targets expose your EFS file system to the instances within your VPC. They are required in every Availability Zone that houses servers needing access.

1. Since both instances are in US East 1C, remove any other availability zones if present.
2. Select the subnet corresponding to US East 1C.
3. Specify a security group (e.g., one named “EFS”) that permits access from your EC2 instances.
4. Confirm the correct VPC is selected.
5. Click Next.

Setting File System Policies

Set file system policies to control access—options include preventing root access or enforcing read-only mode. For this demo, leave the defaults.

Review your settings and click Create. The file system will initially appear in a "creating" state. Refresh the page until it becomes available.

Preparing the EC2 Instances

For both instances, install the Amazon EFS Utils package to simplify mounting EFS on Amazon Linux images.

On instance 1 (apply the same on instance 2), run:

sudo yum install -y amazon-efs-utils

The output will display information similar to the following:

Last metadata expiration check: 0:10:13 ago on Wed May  3 04:05:58 2023.
Dependencies resolved.
.
Package                       Architecture     Version                  Repository               Size
====================================================================================================================
Installing:
amazon-efs-utils              noarch           1.35.0-1.amzn2023        amazonlinux              56 k
Installing dependencies:
stunnel                       x86_64           5.58-1.amzn2023.0.2      amazonlinux             156 k

Transaction Summary
====================================================================================================================
Install  2 Packages

Total download size: 212 k
Installed size: 556 k
Downloading Packages:
(1/2): amazon-efs-utils-1.35.0-1.amzn2023.noarch.rpm
(2/2): stunnel-5.58-1.amzn2023.0.2.x86_64.rpm
--------------------------------------------------------------------------------------------------------------------
Total
Downloading Packages:
(1/2): amazon-efs-utils-1.35.0-1.amzn2023.noarch.rpm               689 kB/s |  56 kB | 00:00
(2/2): stunnel-5.58-1.amzn2023.0.2.x86_64.rpm                      1.5 MB/s    | 156 kB | 00:00
--------------------------------------------------------------------------------------------------------------------

Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
  Preparing   : stunnel-5.58-1.amzn2023.0.2.x86_64                    1/1
  Installing  : stunnel-5.58-1.amzn2023.0.2.x86_64                    1/2
  Running scriptlet: stunnel-5.58-1.amzn2023.0.2.x86_64
  Installing  : amazon-efs-utils-1.35.0-1.amzn2023.noarch             2/2
  Running scriptlet: amazon-efs-utils-1.35.0-1.amzn2023.noarch
  Verifying   : stunnel-5.58-1.amzn2023.0.2.x86_64                    1/2
  Verifying   : amazon-efs-utils-1.35.0-1.amzn2023.noarch             2/2

Installed:
  amazon-efs-utils-1.35.0-1.amzn2023.noarch

Complete!

Mounting the EFS File System

Step 1: Create the Mount Directory

On instance 1, create a directory where the EFS file system will be mounted:

sudo mkdir /efsdemo

Step 2: Mount the EFS File System

To mount the EFS file system, use the mount.efs command with two arguments:

• The EFS file system ID (copy it from your AWS console under EFS details).
• The target directory (e.g., /efsdemo).

For example, on instance 1, execute:

[ec2-user@ip-172-31-88-238 ~]$ sudo mount.efs fs-02f4d38ba0c836aa /efsdemo

Verify the mount by running:

df -h

Expected output:

Filesystem                                          Size  Used Avail Use% Mounted on
fs-02f4d38ba0c8c36aa.efs.us-east-1.amazonaws.com:/  8.0E     0  8.0E   0% /efsdemo

Step 3: Make the Mount Persistent

To automatically mount the file system after a reboot, update the /etc/fstab file. Add a new line with your file system ID and mount point:

fs-02f4d38ba0c8c36aa:/efsdemo efs _netdev,noresvport,tls,iam 0 0

An example /etc/fstab file:

UUID=d0c265c4-6ea1-4060-b815-520e1c2aae05 /                       xfs     defaults,noatime        1 1
UUID=600C-CF35      /boot/efi               vfat    defaults,noatime,uid=0,gid=0,umask=0077,shortname=winnt,x-systemd.automount 0 2
fs-02f4d38ba0c8c36aa:/efsdemo efs _netdev,noresvport,tls,iam 0 0

After modifying /etc/fstab, mount all file systems with:

sudo mount -a

Then, verify the mount using:

df -h

Sharing Files Between Instances

To test the shared file system, create a file on instance 1 in the /efsdemo directory:

sudo vi /efsdemo/file1.txt

For instance, add the content:

I made this file on instance1

Next, perform the following on instance 2:

1. Create the mount directory (if it doesn’t exist yet):

   sudo mkdir /efsdemo
   

2. Mount the EFS file system using the same command as on instance 1:

   sudo mount -t efs fs-02f4d38ba0c8c36aa:/ /efsdemo
   

3. Verify the mount:

   df -h
   

4. Navigate to /efsdemo and verify that file1.txt exists:

   cd /efsdemo
   ls
   cat file1.txt
   

5. Optionally, create another file on instance 2:

   sudo vi /efsdemo/file2.txt
   

   Add the content:

   I made this file on instance2
   

6. Return to instance 1 to ensure both files are visible:

   ls /efsdemo
   cat /efsdemo/file2.txt
   

This verifies that changes on one instance are visible on the other, showcasing the sharing capability of AWS EFS.

Cleaning Up

To conclude the demo, delete the EFS file system through the AWS console:

1. Select your EFS file system and click Delete.
2. When prompted, copy the file system name, paste it into the confirmation box, and confirm deletion.

After a few minutes, the file system will be successfully deleted.