Installation and First Login

Installation Options link

Download ISOs from official sites only (ubuntu.com, debian.org, getfedora.org). Verify SHA256 checksums when provided.

  # Verify ISO checksum (on Linux/macOS)
sha256sum ubuntu-24.04-live-server-amd64.iso
# Compare output to published hash on download page
  

Typical Install Steps link

1. Create bootable USB with dd, Rufus, or Etcher
2. Boot from USB; choose language, keyboard, and timezone
3. Partition disk — Erase disk for dedicated machines, manual layout for dual-boot
4. Create a user account (avoid daily use as root)
5. Install bootloader (GRUB) and reboot
6. Remove install media when prompted

Recommended Partitions (manual layout) link

For servers, a single / partition is often sufficient. Separate /var helps when logs grow unbounded.

  # After install — verify partitions
lsblk -f
df -h
  

First Login link

  # Update system immediately (Debian/Ubuntu)
sudo apt update && sudo apt upgrade -y

# Fedora/RHEL family
sudo dnf upgrade -y

# Check disk and memory
df -h
free -h
swapon --show
  

Set timezone and NTP sync:

  timedatectl
sudo timedatectl set-timezone America/New_York
sudo timedatectl set-ntp true
  

Post-Install Essentials link

  # Common tools (Debian/Ubuntu)
sudo apt install -y curl wget git vim htop tree unzip \
    build-essential ca-certificates gnupg lsb-release

# Fedora/RHEL
sudo dnf install -y curl wget git vim htop tree unzip \
    gcc make ca-certificates

# Enable automatic security updates (Ubuntu)
sudo apt install unattended-upgrades
sudo dpkg-reconfigure -plow unattended-upgrades
  

Create a sane .vimrc or install your preferred editor. Set EDITOR in ~/.bashrc.

SSH Access (servers and VMs) link

  # Install and enable SSH server
sudo apt install openssh-server
sudo systemctl enable --now ssh

# Verify listening
ss -tlnp | grep :22

# Find IP address
ip -4 addr show | grep inet
hostname -I
  

Connect from another machine:

  ssh [email protected]
ssh -v user@host    # verbose for debugging
  

Cloud-Init First Boot link

Cloud images (AWS, GCP) configure users, SSH keys, and packages via cloud-init:

  # Check cloud-init status
cloud-init status
sudo cat /var/log/cloud-init-output.log

# User data location
ls /var/lib/cloud/instance/
  

Do not manually fight cloud-init on cloud VMs — use user-data scripts or Terraform instead.

Secure the Fresh Install link

  # Create sudo user if you installed as root-only
sudo adduser deploy
sudo usermod -aG sudo deploy

# Basic firewall (Ubuntu)
sudo ufw allow OpenSSH
sudo ufw enable

# Disable root SSH login (after key auth works)
sudo sed -i 's/^#*PermitRootLogin.*/PermitRootLogin no/' /etc/ssh/sshd_config
sudo systemctl reload ssh
  

Checklist before exposing to the internet:

• Apply all updates
• Strong passwords or SSH keys only
• Firewall enabled with minimal open ports
• Non-root daily account with sudo
• Fail2ban or cloud-level brute-force protection

Best Practices link

Common Mistakes link

Troubleshooting link

Boot failure after install: Boot from live USB, run fsck on partitions, verify GRUB installed to correct disk (efibootmgr -v on UEFI systems).

Cannot SSH after cloud launch: Check security group/firewall allows port 22; verify key pair matches; read cloud-init-output.log.

Wrong keyboard layout: sudo dpkg-reconfigure keyboard-configuration (Debian/Ubuntu).

Production Scenario link

An ops team provisions Ubuntu 24.04 LTS on AWS with Terraform:

1. User-data installs nginx, sets hostname, adds SSH keys for deploy user
2. Post-boot Ansible hardens SSH, configures UFW, installs monitoring agent
3. Golden AMI baked monthly with security patches for faster scaling
4. Separate /var on 50 GB volume for log retention

First boot completes in under 3 minutes; the instance passes health checks before joining the load balancer.

A clean first boot sets the tone: patched system, non-root daily account, SSH ready, and firewall enforcing least-privilege network access.