Instruqt packer image for K3s

This repo contains the source files to build a K3s image for Instruqt.

What's includes:

• K3s

• Helm

• Kubernetes dashboard

  • To update to the latest dashboard:

    GITHUB_URL=https://github.com/kubernetes/dashboard/releases
    VERSION_KUBE_DASHBOARD=$(curl -w '%{url_effective}' -I -L -s -S "${GITHUB_URL}/latest" -o /dev/null | sed -e 's|.*/||')
    curl -sL -o files/dashboard.yml "https://raw.githubusercontent.com/kubernetes/dashboard/${VERSION_KUBE_DASHBOARD}/aio/deploy/recommended.yaml"
    # Enable skipping login page
    sed -i '/--namespace=kubernetes-dashboard/a \            - --enable-skip-login' files/dashboard.yml
    

• Systemd service for kubectl proxy

• Bash script to wait for Kubernetes dashboard to start and print the dashboard token (/usr/bin/start.sh)

• Kubectl completion (see section on how to enable kubectl autocompletion)

Current active images

Images are built upon releases on the K3s repo. This is a list of images available:

instruqt/k3s-v1-21-1

instruqt/k3s-v1-20-4

instruqt/k3s-v1-19-8

instruqt/k3s-v1-18-16

instruqt/k3s-v1-18-8

instruqt/k3s-v1-18-6

instruqt/k3s-v1-18-4

instruqt/k3s-v1-18-3

instruqt/k3s-v1-18-2

instruqt/k3s-v1-17-11

instruqt/k3s-v1-17-9

instruqt/k3s-v1-17-7

instruqt/k3s-v1-17-6

instruqt/k3s-v1-17-5

instruqt/k3s-v1-17-4

Usage on Instruqt

There is no need to build this packer image yourself. It has already been built. We advise you to use machine type n1-standard-2 or higher to ensure stability.

How to configure this image in your config.yml

Use the following config in your Instruqt config.yml to use this image:

version: "2"
virtualmachines:
- name: kubernetes
  image: instruqt/k3s-v1-20-4
  shell: /usr/bin/start.sh
  machine_type: n1-standard-2

How to configure this image in the web interface

Use the following config in your Instruqt track:

Multi-node clusters

This image supports creating multi-node cluster (starting with k3s version 1.21.1 instruqt/k3s-v1-21-1). Multi-node clusters contain 2 types of machines:

• One Control Plane server
• Zero or more Worker nodes

The configuration for the Control Plane server is exactly the same as for a single node setup. To add a worker node to this cluster:

1. Add another virtual machine, using the same image (e.g. instruqt/k3s-v1-21-1)
2. On that VM, add an environment variable K3S_CONTROL_PLANE_SERVER. The value must be the hostname of the Control Plane server.

This will switch it's runtime mode to Worker, and will join the cluster defined by the Control Plane server.

Example config.yml

version: "2"
virtualmachines:
- name: server
  image: instruqt/k3s-v1-21-1
  shell: /usr/bin/start.sh
  machine_type: n1-standard-2
- name: worker1
  image: instruqt/k3s-v1-21-1
  shell: /bin/bash
  machine_type: n1-standard-2
  environment:
    K3S_CONTROL_PLANE_HOSTNAME: server
- name: worker2
  image: instruqt/k3s-v1-21-1
  shell: /bin/bash
  machine_type: n1-standard-2
  environment:
    K3S_CONTROL_PLANE_HOSTNAME: server

Enabling kubectl autocompletion

To enable kubectl autocompletion, add the following lines to the setup script of your first challenge:

#!/bin/bash
until [ -f /opt/instruqt/bootstrap/host-bootstrap-completed ]
do
    sleep 1
done

echo "source /usr/share/bash-completion/bash_completion" >> /root/.bashrc
echo "complete -F __start_kubectl k" >> /root/.bashrc