Prepare workstation and the lab tools

Phase 10 · Prepare workstation and the lab tools (~20 min)

• Check the everyday tools are installed.
• Log in to both servers with an SSH key, as student and as root.
• Install the lab command and confirm the lab is ready.

VM: check the everyday tools

The lab profile installed these on every VM. Check that they are there on workstation:

rpm -q man-db man-pages tree tmux bind-utils lsof nano vim-enhanced
man --version | head -1

Every line should show a package version. If one says not installed, follow Repair an existing lab.

VM: bring workstation up to date

sudo dnf -y upgrade                  # password: student

VM: set up vim and tmux

Four spaces instead of tabs, line numbers and highlighted search, so editing files in the later chapters is comfortable. Each command writes one small file:

printf '%s\n' 'set number' 'set autoindent' 'set tabstop=4' 'set shiftwidth=4' 'set expandtab' 'set hlsearch' > ~/.vimrc

printf '%s\n' 'set -g mouse on' 'set -g history-limit 10000' > ~/.tmux.conf

VM: reach both servers by name

The lab's DNS knows every machine by its full name, and the search domain lets you use the short name too.

getent hosts servera.lab.example.com     # 172.25.250.10 servera.lab.example.com
ping -c2 serverb                         # short names work

VM: an SSH key for student, on both servers

Make a key pair and copy its public half to student on each server. Each server asks for the password student once; after that, logins need no password. Chapter 10 explains how keys work; for now, this is what lets you and the lab tools move between machines quickly.

ssh-keygen -t ed25519 -N '' -f ~/.ssh/id_ed25519
for h in servera serverb; do
  ssh-copy-id -o StrictHostKeyChecking=accept-new student@$h.lab.example.com
  ssh -o StrictHostKeyChecking=accept-new student@$h true     # trust the short name too
done
ssh student@servera hostname         # servera.lab.example.com, no password asked

VM: let the same key log in as root

lab grade checks your work on the servers as root, the way a classroom's own tools do. The servers refuse root logins with a password but accept them with a key, so put the same key in root's authorized_keys. Each server asks for the sudo password, student, once:

for h in servera serverb; do
  ssh -t student@$h 'sudo install -d -m 700 /root/.ssh &&
    sudo install -m 600 ~/.ssh/authorized_keys /root/.ssh/authorized_keys &&
    sudo restorecon -R /root/.ssh'
done
ssh root@servera id                  # uid=0(root), no password asked
ssh root@serverb hostname            # serverb.lab.example.com

Running it again is harmless: it replaces root's key list with the same single key.

VM: install the lab command

In a training classroom, each exercise starts with lab start NAME. That command exists only inside the classroom, so this site provides its own small script with the same syntax. It downloads each exercise's starter files from this site and checks your results on the servers. It is a short shell script; read it first if you like.

mkdir -p ~/.local/bin
curl -fsSL https://kernelpath.dev/lab/lab -o ~/.local/bin/lab
chmod +x ~/.local/bin/lab
lab version                          # lab 6
lab check                            # every line PASS

VM: don't create practice files yet

Leave workstation as it is for now. Your first practice folder comes in section 1.8, after the clean snapshot, so the baseline contains the tools but none of your work.