Rest time

From a long work week finally got rest since I don't have any classes this saturday that gave me a lot of time to rest.

While i'm at it, stumbled upon a cool project called K3s it is a lightweight kubernetes project by Rancher so while resting I will try to install it with Vagrant VMs and Ansible

Vagrant for ease

Vagrant is a tool made by Hashicorp to provision VMs in any provider, in my case I will use VirtualBox.

Created my vagrant file first.

# vagrant init

It will initialize a file named Vagrantfile in my directory then I will edit it for my requirement

# vim Vagrantfile
Vagrant.configure("2") do |config|

	(1..3).each do |i|
		config.vm.define "worker#{i}" do |worker|
			worker.vm.box = "ubuntu/xenial64"
			worker.vm.network "private_network", ip: "192.168.0.11#{i}", virtualbox__intnet: true
			worker.vm.provider "virtualbox" do |workervm|
				workervm.memory = 4096
				workervm.cpus = 2
			end
			worker.vm.provision "shell", path: "worker.sh"
			worker.vm.hostname = "worker#{i}.ajohnsc.io"
		end
	end

	config.vm.define "master" do |master|
		master.vm.box = "ubuntu/xenial64"
		master.vm.network "private_network", ip: "192.168.0.110", virtualbox__intnet: true
		master.vm.provider "virtualbox" do |mastervm|
			mastervm.memory = 4096
			mastervm.cpus = 2
		end
		master.vm.provision "shell", path: "master.sh"
		master.vm.hostname = "master.ajohnsc.io"
	end

end

So this is my final Vagrant file, it will provision 1 master and 3 worker nodes with all internal IPs and hostnames, it uses a "provisioning" concept that I can pass scripts to my nodes via shell or ansible. however the default boxes of Vagrant doesn't come with ansible thus I created specific scripts for workers and master nodes.

Back to shell scripting

I wanted to install the K3s cluster using Ansible however Vagrant won't allow me thus I can pass the Ansible playbooks inside the scripts.

For my worker scripts all I want to have a user named kubecfg with the default keys that I created, with passwordless sudo:

#/bin/bash

# create kubecfg user
sudo useradd -m kubecfg

# create ssh directory
sudo mkdir -p /home/kubecfg/.ssh

# copy keys to .ssh directory
sudo cp /vagrant/keys/* /home/kubecfg/.ssh/

# make kubecfg authorized by the same key
sudo cp /home/kubecfg/.ssh/id_rsa.pub /home/kubecfg/.ssh/authorized_keys

# Change ownership
sudo chown -R kubecfg. /home/kubecfg/.ssh/

# Change permissions
sudo chmod 700 /home/kubecfg/.ssh/
sudo chmod 600 /home/kubecfg/.ssh/id_rsa
sudo chmod 644 /home/kubecfg/.ssh/id_rsa.pub
sudo chmod 700 /home/kubecfg/.ssh/authorized_keys

# Make kubecfg sudoer
echo "kubecfg ALL=(ALL)	NOPASSWD: ALL" | sudo tee -a /etc/sudoers.d/kubecfg

For my master script same as the worker but I want it to install ansible to the master node and install K3s using my playbook that I created.

#/bin/bash

# create kubecfg user
sudo useradd -m kubecfg

# create ssh directory
sudo mkdir -p /home/kubecfg/.ssh

# copy keys to .ssh directory
sudo cp /vagrant/keys/* /home/kubecfg/.ssh/

# make kubecfg authorized by the same key
sudo cp /home/kubecfg/.ssh/id_rsa.pub /home/kubecfg/.ssh/authorized_keys

# Change ownership
sudo chown -R kubecfg. /home/kubecfg/.ssh/

# Change permissions
sudo chmod 700 /home/kubecfg/.ssh/
sudo chmod 600 /home/kubecfg/.ssh/id_rsa
sudo chmod 644 /home/kubecfg/.ssh/id_rsa.pub
sudo chmod 700 /home/kubecfg/.ssh/authorized_keys

# Make kubecfg sudoer
echo "kubecfg ALL=(ALL)	NOPASSWD: ALL" | sudo tee -a /etc/sudoers.d/kubecfg

# install ansible
sudo apt-add-repository ppa:ansible/ansible
sudo apt-get update
sudo apt-get install ansible -y

# run ansible playbook as kubecfg user
sudo su - kubecfg -c "cd /vagrant/k3sdeploy;ansible-playbook main.yaml"

Ansible is the way

Since everything is ready I can now create my Ansible playbook to install the K3s cluster

First I need the configuration file for ansible

# cat ansible.cfg
[defaults]

inventory      = ./inventory
remote_user = kubecfg
host_key_checking = false

[privilege_escalation]
become=True
become_method=sudo
become_user=root
become_ask_pass=False

I want my ansible playbook to get my inventory from my local inventory file and won't do host checking since all users are newly created via vagrant, also I want to use kubecfg user for remote user with privilege escalations.

This is my inventory file:

# cat inventory
[master]
192.168.0.110

[worker]
192.168.0.111
192.168.0.112
192.168.0.113

Since my IP is defined using Vagrant my inventory was easier to create

Then this is my playbook to install K3s

# cat main.yaml
---
- name: Deploy K3s Master
  hosts: master

  tasks:
  - name: install k3s using k3s script
    shell: >
      curl -sfL https://get.k3s.io | sh -s - server --bind-address 192.168.0.110 --advertise-address 192.168.0.110

  - name: get node token
    slurp:
      src: /var/lib/rancher/k3s/server/node-token
    register: token

  - name: add token holder
    add_host:
      name: "K3S_TOKEN_HOLDER"
      token: "{{ token.content | b64decode }}"

- name: Deploy k3s workers
  hosts: worker

  tasks:
  
  - name: install k3s using k3s script
    shell: >
      curl -sfL https://get.k3s.io | K3S_URL='https://192.168.0.110:6443' K3S_TOKEN="{{ hostvars['K3S_TOKEN_HOLDER']['token'] }}" sh -

I used the installation script of K3s in my ansible playbook for easier installation then get the token from the master node to install the agents in the worker nodes.

Make it simple

Since I want to make it simple you can simply get all of these in my repository:

# git clone git clone https://github.com/ajohnsc/K3sVagrant.git
# cd K3sVagrant
# vagrant up

Then you will have your own K3s cluster using vagrant and Ansible.