Conncet Ubuntu EC2 instance to GitHub

How to Connect an Ubuntu EC2 Instance to GitHub and Clone a Repository

Ankit Tripathi

Published Oct 3, 2026

Last modified Oct 5, 2026

🔐 Connect GitHub to AWS EC2 Using SSH

Topic: GitHub SSH Authentication
Purpose: Connect an EC2 instance to GitHub so the EC2 server can clone, pull, and push repositories without repeatedly entering GitHub credentials.

📌 1. Basic Concept

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                         SSH Authentication
                                
        AWS EC2  ───────────────────────────►  GitHub
           │                                      │
           │                                      │
     Private Key 🔐                         Public Key 🔑
     id_ed25519                            id_ed25519.pub

SSH Key Pair

When we create an SSH key, two files are generated:

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~/.ssh/
├── id_ed25519       🔐 Private Key
└── id_ed25519.pub   🔑 Public Key

Key	Location	Purpose	Share?
Private Key	~/.ssh/id_ed25519	Used by EC2 for authentication	❌ NEVER
Public Key	~/.ssh/id_ed25519.pub	Added to GitHub	✅ Yes
known_hosts	~/.ssh/known_hosts	Stores trusted SSH hosts	🔒 Keep on EC2
authorized_keys	~/.ssh/authorized_keys	Allows SSH access to EC2	🔒 Keep on EC2

🔐 Golden Rule

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Private Key  → stays on EC2

Public Key   → goes to GitHub

Never share or upload the private key.

🚀 2. New EC2 → GitHub Setup

Whenever a new EC2 instance is created, follow these steps.

Step 1 — Check Git

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git --version

What does it mean?

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git
 ↓
Git program

--version
 ↓
Show installed Git version

Example:

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git version 2.43.0

If Git is not installed

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sudo apt update
sudo apt install git -y

Then verify:

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git --version

🔑 3. Check Existing SSH Key

Before creating a new SSH key, check whether one already exists.

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ls -la ~/.ssh

Look for:

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id_ed25519
id_ed25519.pub

Example:

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~/.ssh/
├── authorized_keys
├── id_ed25519
├── id_ed25519.pub
└── known_hosts

If the keys already exist

If you already have:

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id_ed25519
id_ed25519.pub

Do NOT create another key unnecessarily.

Use the existing key.

🆕 4. Create SSH Key If It Does Not Exist

If id_ed25519 and id_ed25519.pub do not exist:

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ssh-keygen -t ed25519 -C "ec2-github"
        or
ssh-keygen

Meaning

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ssh-keygen
    ↓
Generate SSH key

-t ed25519
    ↓
Use Ed25519 key type

-C "ec2-github"
    ↓
Add a recognizable comment

When asked:

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Enter file in which to save the key (/home/ubuntu/.ssh/id_ed25519):

Press:

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Enter

For the passphrase:

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Enter passphrase (empty for no passphrase):

Press:

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Enter

Then:

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Enter same passphrase again:

Press:

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Enter

The following files will be created:

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~/.ssh/
├── id_ed25519
└── id_ed25519.pub

🔍 5. Get the Public SSH Key

Run:

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cat ~/.ssh/id_ed25519.pub

Example:

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ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAI...... ec2-github

Copy the entire line.

⚠️ DO NOT run:

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cat ~/.ssh/id_ed25519

That displays the private key.

Never share the private key.

🌐 6. Add Public Key to GitHub

Go to:

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GitHub
  ↓
Settings
  ↓
SSH and GPG keys
  ↓
New SSH key

Enter:

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Title:
AWS EC2

Select:

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Key type:
Authentication Key

Paste the output of:

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cat ~/.ssh/id_ed25519.pub

Then click:

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Add SSH key

🧪 7. Test EC2 → GitHub SSH Connection

Run:

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ssh -T git@github.com

The first time, you may see:

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Are you sure you want to continue connecting
(yes/no/[fingerprint])?

Type:

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yes

Successful result

You should see:

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Hi YOUR_GITHUB_USERNAME! You've successfully authenticated,
but GitHub does not provide shell access.

✅ This is NOT an error.

The important part is:

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You've successfully authenticated

This means:

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EC2 ───── SSH ─────► GitHub
          ✅

📥 8. Clone GitHub Repository

Go to your GitHub repository:

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Repository
   ↓
Code
   ↓
SSH

GitHub will give you an SSH URL:

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git@github.com:USERNAME/REPOSITORY.git

Example:

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git@github.com:ankittripathidevs/DevOps_FullCourse.git

Clone:

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git clone git@github.com:ankittripathidevs/DevOps_FullCourse.git

Then:

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ls

Example:

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DevOps_FullCourse

Enter the repository:

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cd DevOps_FullCourse

Check:

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git status

⚠️ 9. SSH URL Is NOT a Command

This:

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git@github.com:ankittripathidevs/DevOps_FullCourse.git

is an SSH Repository URL.

❌ Don't run it directly:

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git@github.com:ankittripathidevs/DevOps_FullCourse.git

Use it with Git:

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git clone git@github.com:ankittripathidevs/DevOps_FullCourse.git

🔗 10. Check Existing GitHub Remote

If the repository is already cloned:

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git remote -v

Example HTTPS remote:

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origin  https://github.com/ankittripathidevs/DevOps_FullCourse.git (fetch)
origin  https://github.com/ankittripathidevs/DevOps_FullCourse.git (push)

This means the repository is using HTTPS.

🔀 11. Change HTTPS → SSH

Change the existing GitHub remote:

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git remote set-url origin git@github.com:ankittripathidevs/DevOps_FullCourse.git

Verify:

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git remote -v

Expected:

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origin  git@github.com:ankittripathidevs/DevOps_FullCourse.git (fetch)
origin  git@github.com:ankittripathidevs/DevOps_FullCourse.git (push)

Now the repository uses:

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SSH

instead of:

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HTTPS

📤 12. Push Code to GitHub

After making changes:

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git add .

Create a commit:

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git commit -m "CI/CD"

Push:

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git push

Because SSH authentication is configured, GitHub should not ask:

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Username for 'https://github.com':

📥 13. Pull Latest Code

To download the latest changes from GitHub:

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git pull

🧠 14. Complete Workflow

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                  NEW EC2 INSTANCE
                         │
                         ▼
                  Install Git
                         │
                         ▼
                 Check SSH keys
                         │
                         ▼
                ls -la ~/.ssh
                         │
               ┌─────────┴─────────┐
               │                   │
          Key exists          No key exists
               │                   │
               │             ssh-keygen
               │                   │
               └─────────┬─────────┘
                         ▼
                  Get Public Key
                         │
                         ▼
            cat ~/.ssh/id_ed25519.pub
                         │
                         ▼
               Add Public Key
                  to GitHub
                         │
                         ▼
              ssh -T git@github.com
                         │
                         ▼
                Authentication ✅
                         │
                         ▼
              git clone SSH_URL
                         │
                         ▼
                  Work on Code
                         │
              ┌──────────┴──────────┐
              │                     │
              ▼                     ▼
           git pull              git push
              │                     │
              └──────────┬──────────┘
                         ▼
                       GitHub

📋 15. Quick Command Cheat Sheet

Check Git

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git --version

Install Git

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sudo apt update
sudo apt install git -y

Check SSH keys

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ls -la ~/.ssh

Create SSH key

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ssh-keygen -t ed25519 -C "ec2-github"

Show public key

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cat ~/.ssh/id_ed25519.pub

Test GitHub SSH

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ssh -T git@github.com

Clone repository

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git clone git@github.com:USERNAME/REPOSITORY.git

Check remote

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git remote -v

Change HTTPS → SSH

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git remote set-url origin git@github.com:USERNAME/REPOSITORY.git

Pull

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git pull

Push

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git push

⚠️ 16. Common Problems

Problem 1 — `Permission denied (publickey)`

Error:

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git@github.com: Permission denied (publickey).

Test:

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ssh -T git@github.com

If authentication fails:

Check SSH key:

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ls -la ~/.ssh

Get public key:

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cat ~/.ssh/id_ed25519.pub

Add that public key to GitHub.
Test again:

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ssh -T git@github.com

Problem 2 — Git asks for GitHub username

Error:

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Username for 'https://github.com':

Check:

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git remote -v

If you see:

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https://github.com/...

change it to SSH:

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git remote set-url origin git@github.com:USERNAME/REPOSITORY.git

Problem 3 — SSH URL typed directly

Wrong:

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git@github.com:USERNAME/REPOSITORY.git

Correct:

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git clone git@github.com:USERNAME/REPOSITORY.git

🔐 17. EC2 SSH Key vs GitHub SSH Key

Do not confuse these two.

AWS EC2 Login

Used to connect your computer → EC2.

Example:

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my-laptop
    │
    │ .pem key
    ▼
   EC2

GitHub SSH Authentication

Used to connect EC2 → GitHub.

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EC2
 │
 │ id_ed25519
 ▼
GitHub

They are separate authentication setups.

⭐ 18. New EC2 Checklist

Use this checklist whenever you create a new EC2:

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[ ] Connect to EC2

[ ] Check Git
    git --version

[ ] Install Git if required
    sudo apt update
    sudo apt install git -y

[ ] Check SSH key
    ls -la ~/.ssh

[ ] If key doesn't exist, create it
    ssh-keygen 

[ ] Get public key
    cat ~/.ssh/id_ed25519.pub

[ ] Add public key to GitHub
    GitHub → Settings → SSH and GPG keys

[ ] Test connection
    ssh -T git@github.com

[ ] Clone repository
    git clone git@github.com:USERNAME/REPOSITORY.git

[ ] Enter project
    cd REPOSITORY

[ ] Verify
    git status

# github # ssh # devops # amazon-ec2 # docker

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Conncet Ubuntu EC2 instance to GitHub

Ankit Tripathi

🔐 Connect GitHub to AWS EC2 Using SSH

📌 1. Basic Concept

SSH Key Pair

🔐 Golden Rule

🚀 2. New EC2 → GitHub Setup

Step 1 — Check Git

What does it mean?

If Git is not installed

🔑 3. Check Existing SSH Key

If the keys already exist

🆕 4. Create SSH Key If It Does Not Exist

Meaning

🔍 5. Get the Public SSH Key

⚠️ DO NOT run:

🌐 6. Add Public Key to GitHub

🧪 7. Test EC2 → GitHub SSH Connection

Successful result

✅ This is NOT an error.

📥 8. Clone GitHub Repository

⚠️ 9. SSH URL Is NOT a Command

🔗 10. Check Existing GitHub Remote

🔀 11. Change HTTPS → SSH

📤 12. Push Code to GitHub

📥 13. Pull Latest Code

🧠 14. Complete Workflow

📋 15. Quick Command Cheat Sheet

Check Git

Install Git

Check SSH keys

Create SSH key

Show public key

Test GitHub SSH

Clone repository

Check remote

Change HTTPS → SSH

Pull

Push

⚠️ 16. Common Problems

Problem 1 — Permission denied (publickey)

Problem 2 — Git asks for GitHub username

Problem 3 — SSH URL typed directly

🔐 17. EC2 SSH Key vs GitHub SSH Key

AWS EC2 Login

GitHub SSH Authentication

⭐ 18. New EC2 Checklist

Problem 1 — `Permission denied (publickey)`