Skip to content

Lab 1 - The Phoenix Server

Lab 1: The Phoenix Server - From Ashes to Automation

Scenario:

Welcome back, specialists. A critical, minimalist web server has suffered a catastrophic failure. The only thing that remains is the client's requirement: a fast, secure, and minimal Debian system. Your task is to rebuild it from the ground up. This isn't just about getting a system running; it's about building it with intention, precision, and an understanding of the components, just like you would in a real-world data center. We will use the Debian netinst (network install) image, which is small and requires you to pull packages from the network, forcing a deliberate choice of what goes into our system.

Prerequisites:

Core Concepts Refresher:

Your LPIC-101/102 knowledge is sound, but a year is a long time. Refresh your memory on:

  • Logical Volume Management (LVM): Why it's superior to standard partitions for server environments (flexibility, snapshots).
  • debootstrap: A tool to install a basic Debian system into a subdirectory of another, already-installed system.
  • chroot: (change root) A way to run commands and an interactive shell within a different root directory. Essential for system recovery and custom builds.

Level 1: The Foundation (Standard Complexity)

Goal: Build a minimal, functional Debian server using the expert guided installer and LVM for a flexible disk layout.

Instructions:

  1. VM Creation:

    • Create a new VM. Name it phoenix-server.
    • Assign it: 2 vCPUs, 2048 MB RAM, and a new 20 GB virtual disk.
    • Mount the Debian netinst ISO and boot the VM.

  2. Expert Installation:

    • From the boot menu, select Advanced options > Expert install. This mode exposes every step of the installation process. Proceed through the initial steps (language, location, keyboard).

  3. Partitioning with LVM (The Core Task):

    • When you reach the partitioning step, choose Manual.
    • Create a new partition table on your virtual disk.
    • Create a small 512MB primary partition at the beginning of the disk. Set its "Use as" type to Ext4 and its mount point to /boot.
    • Create a second, larger primary partition using the remaining space. Set its "Use as" type to physical volume for LVM.
    • Now, navigate to the "Configure the Logical Volume Manager" menu.
    • Create a Volume Group (VG) named vg_phoenix.
    • Inside vg_phoenix, create three Logical Volumes (LVs):
      • lv_root: 10 GB, to be used for the root filesystem (/).
      • lv_home: 5 GB, to be used for user data (/home).
      • lv_swap: 2 GB, to be used for swap space.
    • Finish the LVM configuration and assign each LV its filesystem type (Ext4 for root/home, swap for swap) and mount point.

  4. Minimal Package Installation:

    • Proceed with the base system installation.
    • When you reach "Software selection," deselect everything, especially the "Debian desktop environment."
    • The only two options that should be checked are:
      • SSH server
      • standard system utilities
    • This ensures our server is lean and has no unnecessary graphical components.

  5. Finalize and Verify:

    • Install the GRUB bootloader to the primary drive (e.g., /dev/vda).
    • Finish the installation and reboot. The system will boot to a command-line interface.
    • From your host machine's terminal, SSH into the new server (ssh user@<vm_ip_address>).
    • Verification Commands: Run the following to confirm your setup. What does each one tell you?
      • lsblk (Should show your LVM layout)
      • df -h (Should show your filesystems mounted)
      • free -m (Should show your swap space is active)
      • dpkg --get-selections | wc -l (How many packages are installed? A minimal system is a happy system.)

Level 2: The Optimization (Advanced Complexity)

Goal: Harden the base installation, automate package deployment, and prepare it for a "production" role.

Instructions:

  1. SSH Hardening:

    • Modify /etc/ssh/sshd_config on phoenix-server to enhance security.
      • Disable root login (PermitRootLogin no).
      • Disable password-based authentication (PasswordAuthentication no).
    • On your host machine, generate an SSH key (ssh-keygen) if you don't have one, and copy the public key to the server (ssh-copy-id user@<vm_ip_address>).
    • Restart the SSH service (systemctl restart sshd) and verify you can still log in (it should now be passwordless).

  2. Firewall Configuration:

    • Install the Uncomplicated Firewall: apt install ufw.
    • Configure it to deny all incoming traffic by default.
    • Explicitly allow SSH traffic. What port does SSH use?
    • Enable the firewall. Verify its status.

  3. Create a Personal Package Repository:

    • On the server, install nginx: apt install nginx.
    • Create a simple dummy Debian package. You don't need to write code; the goal is to create the package structure. 
      # Install packaging tools
sudo apt install build-essential devscripts debhelper
# Create a project
mkdir ~/dummy-pkg-1.0 && cd ~/dummy-pkg-1.0
dh_make --native -s -y
# Build the package (ignore warnings)
debuild -us -uc
    • You will find a .deb file in the parent directory.
    • Create a directory in the nginx web root (/var/www/html/debian) and copy your .deb file there.
    • Configure nginx to serve this directory.
    • On the server itself, add your own nginx server as an APT repository in /etc/apt/sources.list.
    • Run apt update and then install your dummy-pkg.

Level 3: The Recovery & Deep Dive (Expert Complexity)

Goal: Simulate a catastrophic failure and rebuild the system without the installer, using only command-line tools. This is the ultimate test of system understanding.

Instructions:

  1. Simulated Disaster: GRUB is Gone!

    • On your working phoenix-server from Level 1, simulate a bootloader overwrite: sudo dd if=/dev/zero of=/dev/vda bs=446 count=1
    • Reboot the VM. It will fail to boot, likely with a "No bootable medium" error. The server is dead. Or is it?

  2. Manual System Rescue:

    • Boot the VM using the Debian netinst ISO again.
    • From the main menu, select Advanced options > Rescue mode.
    • The rescue environment will try to find your existing installation. Let it guide you to mount your LVM root partition under /target. If it fails, you must do it manually using the provided shell.
    • The key step: chroot /target. You are now inside your broken system, with the tools from the live CD.
    • Your task: From within the chroot, fix the system. What commands do you need to run?
      • You'll need to mount /boot.
      • You'll need to reinstall GRUB. (Hint: grub-install /dev/vda)
      • You might need to update GRUB's configuration.
    • Exit the chroot, reboot without the ISO, and watch your server rise from the ashes.

  3. The debootstrap Challenge:

    • If you complete the rescue, the final challenge awaits. Destroy your VM and create a new one.
    • This time, do not use the installer at all. Boot into Rescue Mode from the start.
    • From the command line, perform a full manual installation:
      1. Partition the disk (parted or fdisk).
      2. Create the LVM structure (pvcreate, vgcreate, lvcreate).
      3. Format the filesystems (mkfs.ext4, mkswap).
      4. Mount everything under /mnt (e.g., root on /mnt, boot on /mnt/boot).
      5. Use debootstrap to install the Debian 'bookworm' release into /mnt.
      6. chroot into /mnt and manually install a kernel (apt install linux-image-amd64), GRUB (apt install grub-pc), configure /etc/fstab, set a root password (passwd), and create a user.
    • If you can successfully boot this manually-built system, you have demonstrated a true mastery of the Linux installation process.