Linux Operations : Shell Scripting & Scaling EBS Storage on EC2

As part of my Linux learning journey, Day 2 focused on two very practical and important areas:

• 🖥️ Shell Scripting Basics

• 💾 Scaling Storage on an EC2 Instance (EBS Volume Management)

Both topics are extremely relevant for anyone moving toward DevOps, Cloud, or System Administration roles. Let’s walk through everything step by step.

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Part 1: Shell Scripting Basics

What is Shell Scripting?

A shell script is simply a sequence of Linux commands written in a file and executed together to automate a task.

Instead of typing commands manually every time, we can:

• Write them in a file

• Give executable permission

• Run them whenever needed

This is the foundation of automation in Linux.

📌 Important: A script must have executable permission before it can be run.

Example:

chmod +x script.sh
./script.sh

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Script Practice Covered

1️⃣ Accepting Input from User

Shell scripts can interact with users by taking input at runtime.
This makes scripts dynamic and more useful in real-world scenarios.

You can use the read command to accept user input.

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2️⃣ Conditional Statements (if / if-else)

Conditional logic allows your script to make decisions.

We practiced:

• if

• if-else

This helps in scenarios like:

• Checking if a file exists

• Validating user input

• Performing actions based on conditions

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3️⃣ Loops

Loops allow repetitive execution of commands until a condition is met.

This is powerful when:

• Processing multiple files

• Running checks continuously

• Automating repetitive tasks

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Why Shell Scripting Matters

Shell scripting is not just about writing commands. It is about:

• Automating repetitive tasks

• Reducing human error

• Saving time

• Managing infrastructure efficiently

For DevOps engineers, this is a must-have skill.

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Part 2: Scaling Storage Capacity of an EC2 Instance

Now comes the real-world cloud scenario.

Imagine your EC2 instance is running out of disk space. What do you do?

There are two approaches:

1. Scale existing EBS volume

2. Create and attach a new EBS volume

Let’s go step by step.

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Option 1: Scaling an Existing EBS Volume

Step 1: Increase Volume Size from AWS Console

First, go to the AWS Console and increase the EBS volume size.

But here’s something important:

Increasing the volume size in AWS does NOT automatically increase the filesystem inside Linux.

The OS still sees the old size until we extend the partition and filesystem.

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Step 2: Extend the Partition

Use:

sudo growpart /dev/xvda 1

This resizes the partition to match the new EBS size.

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Step 3: Extend the Filesystem

Check disk usage:

df -hT

If changes are not visible, extend the filesystem (for XFS):

sudo xfs_growfs -d /

Then verify again:

df -hT

Now your storage expansion is complete.

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Option 2: Create and Attach a New EBS Volume

Sometimes instead of resizing, you may want to attach a new volume.

⚠️ Important:
The new EBS volume must be created in the same Availability Zone as the EC2 instance.

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Step 1: Attach Volume & Verify

After attaching the volume, check available disks:

lsblk

You’ll notice the new device (e.g., /dev/xvdf) with no mount point.

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Step 2: Check If Filesystem Exists

sudo file -s /dev/xvdf

• If output shows data → No filesystem exists.

• If it shows xfs → Filesystem already exists.

⚠️ Creating a new filesystem will erase existing data.

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Step 3: Create Filesystem

sudo mkfs -t xfs /dev/xvdf

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Step 4: Create Mount Directory

sudo mkdir /data

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Step 5: Mount the Volume

sudo mount /dev/xvdf /data

Verify:

df -hT

Now the volume is usable.

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Making the Mount Persistent (Very Important)

If you reboot the instance now, the mount will disappear.

To make it permanent:

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Step 1: Get UUID

sudo blkid

Copy the UUID of the new volume.

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Step 2: Update /etc/fstab

sudo vi /etc/fstab

Add an entry using UUID (recommended because UUID is globally unique).

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Step 3: Validate Configuration

sudo mount -a

If no error appears, your configuration is correct.

You can reboot the instance to verify.

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Key Learnings from Day 2

✔ Shell scripting is the foundation of automation
✔ Increasing EBS size is a two-step process (cloud + filesystem)
✔ Always verify partition and filesystem
✔ Never create filesystem blindly — it erases data
✔ Use UUID in fstab for reliable mounting
✔ Always test with mount -a before reboot

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Final Thoughts

Today’s session was practical and production-oriented.

Understanding:

• How storage works internally

• How filesystems behave

• How mounting works

• How automation begins with shell scripting

These are real-world skills that every DevOps or Cloud Engineer must know.

Linux is not just about commands — it’s about understanding how systems actually function.

More hands-on learning coming next 🚀