01-intro

Lab 1

Git Intro

You will keep all the code (and more) written during this course in a Git repository.

Teachers will check your work in your Git repo -- not in your text editor. Having all the tasks completed with results pushed to your Git repository is a requirement to access the exam.

GitHub is a well-known and widely used (but not the only one) service to host Git repositories. We'll use GitHub for this course as a collaboration platform.

If you feel some lack of experience with Git and GitHub we recommend to read this tutorial. It's also ok to use GUI version if you prefer: GitHub Desktop

Ansible Intro

We will use Ansible in this course as a configuration management tool. There are dozens of configuration management tools out there but we've chosen Ansible as one of the simplest one to get started with.

You can run Ansible from your laptop directly in case you have Linux or MacOS. In case you have Windows, you can run Ansible in WSL.

Task 1: Set up your Git repository

If you have a GitHub account already, skip this step. Otherwise create a new GitHub account. The most basic free account is more than enough -- you won't need any premium GitHub features for this course.

Create a GitHub repository named ica0002. Choose "Add a README file". Note: this repository should be private!

Add our course bot as a collaborator to your repository. This is needed for the teachers to provision virtual machines for you to practice, and check your task submissions. Go to your new repository settings, select Collaborators in the left menu, click Add people and add user ica0002-bot (here is its GitHub profile: https://github.com/ica0002-bot).

Once you have completed all the steps above your repository should appear in this list automatically after some time (up to 30m). If it does not, please ask the teachers for help.

Note: You don't have to wait until your repository is added to this list, you can continue with the next task.

Task 2: Set up SSH keys

(on a Control node -- same machine you'll be running Ansible from)

If you have an SSH keypair already you can reuse it for this course. You can check for existing SSH keys on your machine by running

ls -la ~/.ssh

If there are files named id_rsa and id_rsa.pub you're probably good to go already. If not, generate a new keypair by running ssh-keygen.

Your public SSH key can be found in ~/.ssh/id_rsa.pub file. Add this key (entire file content) to your GitHub account:

• In GitHub web UI click your profile icon in the top right corner
• Select Settings
• Select SSH and GPG keys in the left menu
• Click New SSH key
• Paste the content of ~/.ssh/id_rsa.pub file to the Key field
• click Add SSH key

Once you have added your public key to your GitHub account our bot should detect it automatically within 2..3 minutes. You can see the result here.

Note: You don't have to wait until your key is added to this list, you can continue with the next task.

Task 3: Install Ansible

(on a Control node -- same machine where your SSH keys reside)

Note: we will use Ansible version 10.1.0 (ansible-core 2.17.1) for this course. Teachers will have this version installed and use it to check your tasks. Your code is considered working only if it executes successfully on Ansible 10.1.0. If you're using other Ansible versions -- you're on your own with them.

Note: you will need Python v3.10 or newer to use this version of Ansible.

For Linux or OS X, we recommend to use Python virtual env:

python3 -m venv ~/ansible-venv
~/ansible-venv/bin/pip install ansible==10.1.0
~/ansible-venv/bin/ansible-community --version
~/ansible-venv/bin/ansible --version

Last command should print something like (minor version might be different):

ansible [core 2.17.1]

Then, add this line to your ~/.profile file (if the file is missing, create it) so you can use 'shorter' commands:

PATH="$HOME/ansible-venv/bin:$PATH"

Logout and log in again. Now this command should also work:

ansible --version

Task 4: Test access to your virtual machine

First, make sure that your Git repository is set up correctly -- check this list for details.

Then, make sure that your virtual machine is set up -- click your name here and find the SSH access details on your page. Note the SSH port number!

Finally, test that SSH access works -- run this command on the control node (replace the 122 with the port number from the list above):

ssh -p122 [email protected] uptime

The command above should print the virtual machine uptime (a few minutes, maybe hours). This means that you can access your virtual machine via SSH.

If you cannot access the virtual machine or it's stuck in 'Creating' state, please ask the teachers for help.

Task 5: Clone your Git repository

(on a Control node -- same machine you'll be running Ansible from)

git clone [email protected]:<your_github_username>/ica0002

Task 6: Create Ansible playbook

(on a Control node -- same machine you'll be running Ansible from)

Example of first playbook you can find here.

Step 1: Move to cloned directory named ica0002.

Step 2: In that directory, create files named ansible.cfg, hosts, roles/init/tasks/main.yaml and infra.yaml -- you can just copy the contents of 01-demo directory from the link above.

Note: directory structure and file names matter! Create the files and directories named exactly as requested.

Step 3: Update your inventory file named hosts -- check your own page from http://193.40.156.67/students.html to find the correct connection parameters.

Step 4: Run the Ansible playbook:

ansible-playbook infra.yaml

You should see only green "ok" messages.

Task 7: Commit and your work to GitHub

Once all the previous tasks are done make sure the files you've created in the Task 6 are pushed to GitHub.

Run these commands to commit your changes:

git add .
git commit -m 'Lab 1'

Finally, run this command to push your changes to GitHub:

git push

Once done, the following files should appear in the root of your GitHub repository:

• ansible.cfg
• hosts
• infra.yaml
• roles/init/tasks/main.yaml