Linux VM vs Windows VM
| Factor | Linux VM | Windows VM |
|---|---|---|
| OS licence cost | Free — no licence fee | Included in VM price (~40% premium) |
| Connection method | SSH (port 22) | RDP (port 3389) |
| Authentication | SSH keys (recommended) or password | Password |
| Typical use | Web servers, containers, cloud-native | Legacy apps, .NET, SQL Server, AD |
| VM name limit | 64 characters | 15 characters |
| Cost (B2s example) | ~₹2,200/month | ~₹4,000/month |
Choosing a Linux Distribution
Azure supports many Linux distributions. Here are the most popular:
| Distribution | Best For | Notes |
|---|---|---|
| Ubuntu Server 22.04 LTS | General use, developers | Most popular, huge community, great documentation |
| Ubuntu Server 20.04 LTS | Stable workloads | Older LTS, still widely used |
| Red Hat Enterprise Linux (RHEL) | Enterprise, regulated industries | Paid licence, enterprise support |
| CentOS Stream | RHEL-compatible workloads | Free, upstream of RHEL |
| Debian | Stable, minimal footprint | Rock-solid stability |
| SUSE Linux Enterprise | SAP workloads | Certified for SAP HANA on Azure |
Recommendation
Start with Ubuntu Server 22.04 LTS. It has the best Azure integration, the largest community, the most documentation, and free OS support. Unless you have a specific reason to use another distro, Ubuntu is the safe default.
SSH Keys — The Right Way to Authenticate
SSH keys are a more secure alternative to passwords. Instead of typing a password every time you connect, you use a pair of cryptographic keys:
- Private key — Stays on your local machine. Never share this.
- Public key — Goes on the VM. Azure installs this automatically during VM creation.
When you connect, SSH uses your private key to prove your identity — no password needed, and much harder to brute-force than a password.
Generate an SSH Key Pair
Bash / PowerShell
Generate SSH key pair
# Works on Windows (PowerShell), macOS, and Linux
ssh-keygen -t rsa -b 4096 -C "your-email@example.com"
# When prompted for file location, press Enter for default:
# Linux/Mac: ~/.ssh/id_rsa
# Windows: C:\Users\YourName\.ssh\id_rsa
# When prompted for passphrase:
# Enter a passphrase for extra security (recommended)
# Or press Enter for no passphrase (convenient but less secure)This creates two files:
id_rsa— Your private key (keep this safe!)id_rsa.pub— Your public key (this goes to Azure)
Never Share Your Private Key
Your private key (
id_rsa) is like a master password. Never share it, never upload it, never put it in a repository. If it's compromised, anyone can access any server where your public key is installed.
Create VM via Azure Portal
The process is almost identical to creating a Windows VM. Key differences:
Image
Search for Ubuntu Server 22.04 LTS in the image selector.
Authentication Type
Select SSH public key (recommended over password):
- Username — e.g.,
azureuser - SSH public key source — Choose "Use existing public key"
- SSH public key — Paste the contents of your
id_rsa.pubfile
Bash
View your public key to copy it
# Linux/Mac
cat ~/.ssh/id_rsa.pub
# Windows PowerShell
Get-Content ~/.ssh/id_rsa.pubInbound Port Rules
Select SSH (22) to allow SSH connections.
Create via Azure CLI (Fastest Method)
The CLI method is significantly faster than the portal. Azure CLI can auto-generate SSH keys if you don't have one:
Azure CLI
Create a Linux VM with SSH keys
# Create resource group
az group create \
--name rg-linux-vm-demo \
--location centralindia
# Create Ubuntu VM with auto-generated SSH keys
# Keys saved to ~/.ssh/id_rsa automatically
az vm create \
--resource-group rg-linux-vm-demo \
--name vm-ubuntu-demo \
--image Ubuntu2204 \
--size Standard_B2s \
--admin-username azureuser \
--generate-ssh-keys \
--location centralindia \
--public-ip-sku Standard
# Open SSH port 22
az vm open-port \
--resource-group rg-linux-vm-demo \
--name vm-ubuntu-demo \
--port 22
--generate-ssh-keys
This flag automatically creates an SSH key pair if one doesn't exist at
~/.ssh/id_rsa. The public key is installed on the VM. The private key stays on your machine. This is the quickest way to get started.
Azure CLI
Get the VM's public IP address
az vm show \
--resource-group rg-linux-vm-demo \
--name vm-ubuntu-demo \
--show-details \
--query publicIps \
--output tsvConnecting via SSH
Once you have the VM's public IP address:
Bash / PowerShell
Connect to the Linux VM via SSH
ssh azureuser@<YOUR-VM-PUBLIC-IP>
# Example:
ssh azureuser@4.188.23.45
# If your key is not at the default location:
ssh -i ~/.ssh/id_rsa azureuser@4.188.23.45The first time you connect, SSH will ask you to verify the host fingerprint:
Output
First connection prompt
The authenticity of host '4.188.23.45' can't be established.
ED25519 key fingerprint is SHA256:abc123...
Are you sure you want to continue connecting (yes/no/[fingerprint])? yesType yes and press Enter. You're now connected to your Linux VM running in Azure!
First Commands After Login
Once connected, here are the first commands to run on a new Ubuntu VM:
Bash
Essential first commands on a new Ubuntu VM
# Update package lists and upgrade all packages
sudo apt update && sudo apt upgrade -y
# Check OS version
lsb_release -a
# Check CPU and memory
nproc # Number of CPUs
free -h # Memory usage
df -h # Disk usage
# Install useful tools
sudo apt install -y curl wget git unzip htop
# Check if the VM can reach the internet
curl https://api.ipify.orgCleaning Up
Azure CLI
Delete the resource group and all resources
az group delete \
--name rg-linux-vm-demo \
--yes \
--no-wait