Ubuntu サーバー 26.04 LTS インストール ガイド

# Download Ubuntu Server 26.04 LTS ISO from the official site
wget https://releases.ubuntu.com/26.04/ubuntu-26.04-live-server-amd64.iso
 
# Verify file integrity
wget https://releases.ubuntu.com/26.04/SHA256SUMS
sha256sum -c SHA256SUMS 2>/dev/null | grep ubuntu-26.04-live-server-amd64.iso

# Example mirrors
wget https://mirrors.edge.kernel.org/ubuntu-releases/26.04/ubuntu-26.04-live-server-amd64.iso
 
# Check https://launchpad.net/ubuntu/+cdmirrors for a full list of mirrors

# Identify the USB drive (double-check the device name to avoid data loss)
lsblk
 
# Write the ISO to the USB drive (replace /dev/sdX with the actual device name)
sudo dd if=ubuntu-26.04-live-server-amd64.iso of=/dev/sdX bs=4M status=progress oflag=sync

/        20 GB   System root
/home    Variable User data
/var     Variable Logs and data
/tmp     5 GB    Temporary files

# Remove the USB drive, reboot, and log in with the user you created
# First, update the system
sudo apt update && sudo apt upgrade -y

# Check current timezone
timedatectl
 
# Set timezone (example: US Eastern)
sudo timedatectl set-timezone America/New_York
 
# Enable network time synchronization
# Note: the default time-sync daemon on a fresh 26.04 install is Chrony
# (chrony.service); timedatectl set-ntp only takes effect with systemd-timesyncd.
# Pick one of the following based on the service you actually use:
 
# Path A: Use Chrony (the 26.04 default) -- manage it with systemctl/chronyc
sudo systemctl enable --now chrony
chronyc tracking          # Check sync status
 
# Path B: Use systemd-timesyncd only (when Chrony is not installed) -- use timedatectl
# sudo timedatectl set-ntp true
# timedatectl show-timesync
 
# Check which service is handling synchronization
systemctl is-active chrony >/dev/null 2>&1 && echo "Using Chrony" || timedatectl show-timesync

# Generate the desired locale
sudo locale-gen en_US.UTF-8
 
# Set as default (if not already)
sudo update-locale LANG=en_US.UTF-8

# Back up the original source list
sudo cp /etc/apt/sources.list.d/ubuntu.sources /etc/apt/sources.list.d/ubuntu.sources.bak
 
# Example: use a closer mirror (26.04 uses DEB822 format)
sudo tee /etc/apt/sources.list.d/ubuntu.sources << 'EOF'
Types: deb
URIs: http://archive.ubuntu.com/ubuntu
Suites: resolute resolute-updates resolute-backports resolute-security
Components: main restricted universe multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg
EOF
 
sudo apt update

# Ubuntu comes pre-installed with ufw (Uncomplicated Firewall)
# Allow SSH connections
sudo ufw allow ssh
 
# Enable the firewall
sudo ufw enable
 
# Check rules
sudo ufw status verbose

# Edit the Netplan configuration
sudo tee /etc/netplan/01-static.yaml << 'EOF'
network:
  version: 2
  renderer: networkd
  ethernets:
    ens33:
      addresses:
        - 192.168.1.100/24
      routes:
        - to: default
          via: 192.168.1.1
      nameservers:
        addresses:
          - 8.8.8.8
          - 1.1.1.1
EOF
 
# Apply the configuration
sudo netplan apply

# Set the hostname
sudo hostnamectl set-hostname my-server
 
# Edit /etc/hosts
echo "127.0.1.1 my-server" | sudo tee -a /etc/hosts

# If using a RAID controller, you may need to switch to AHCI mode in BIOS
# or manually load drivers during installation

sudo apt install linux-firmware