Operator Day 2021 Demo Charm

Overview
Quickstart
Development Setup
Build and Deploy Locally
Testing
Get Help & Community
More Information/Related

Overview

This charm is a demonstration of a charm implemeting the sidecar pattern used during Operator Day 2021. You can grab the slides from the demo here.

The charm is written using the Charmed Operator Framework. It deploys gosherve, relying upon the charm container to populate a shared volume with a simple landing-page style website and configure the app before it is started.

Slides for the demo are available and there is a supporting Github Gist that contains copy-and- pastable content from the slide deck.

The finished charm is published on Charmhub.

The charm will:

Deploy a container running gosherve
Fetch a website from Github
Place the downloaded file in a storage volume
Expose a redirect-map config item to configure gosherve redirects
Expose a pull-site action to pull the latest version of the test site
Utilise an ingress relation using the nginx-ingress-integrator library

Each branch of this repository represents a different stage from the demonstration:

Quickstart

Assuming you already have Juju installed and bootstrapped on a cluster (if you do not, see the next section):

# Create a juju model
$ juju add-model dev
# Deploy the charm
$ juju deploy hello-kubecon
# Deploy the ingress charm
$ juju deploy traefik-k8s --trust
$ juju config traefik-k8s external_hostname=juju.local
$ juju config traefik-k8s routing_mode=subdomain
# Relate our app to the ingress
$ juju relate hello-kubecon traefik-k8s
# Wait for the deployment to complete
$ watch -n1 --color juju status --color
# Add an entry to /etc/hosts
$ echo "<traefik-k8s-address> dev-hello-kubecon.juju.local" | sudo tee -a /etc/hosts

You should be able to visit http://dev-hello-kubecon.juju.local in your browser.

Development Setup

To set up a local test environment with MicroK8s:

# Install MicroK8s
$ sudo snap install --classic microk8s
# Wait for MicroK8s to be ready
$ sudo microk8s status --wait-ready
# Enable features required by Juju controller & charm
$ sudo microk8s enable storage dns metallb
# (Optional) Alias kubectl bundled with MicroK8s package
$ sudo snap alias microk8s.kubectl kubectl
# (Optional) Add current user to 'microk8s' group
# This avoid needing to use 'sudo' with the 'microk8s' command
$ sudo usermod -aG microk8s $(whoami)
# Activate the new group (in the current shell only)
# Log out and log back in to make the change system-wide
$ newgrp microk8s
# Install Charmcraft
$ sudo snap install charmcraft
# Install juju
$ sudo snap install --classic juju
# Bootstrap the Juju controller on MicroK8s
$ juju bootstrap microk8s micro
# Add a new model to Juju
$ juju add-model dev

Build and Deploy Locally

# Clone the charm code
$ git clone https://github.com/jnsgruk/hello-kubecon && cd hello-kubecon
# Build the charm package
$ charmcraft pack
# Create a juju model
$ juju add-model dev
# Deploy!
$ juju deploy ./hello-kubecon_ubuntu-20.04-amd64.charm --resource gosherve-image=jnsgruk/gosherve:latest
# Deploy the ingress charm
$ juju deploy traefik-k8s --trust
$ juju config traefik-k8s external_hostname=juju.local
$ juju config traefik-k8s routing_mode=subdomain
# Relate our app to the ingress
$ juju relate hello-kubecon traefik-k8s
# Wait for the deployment to complete
$ watch -n1 --color juju status --color
# Add an entry to /etc/hosts
$ echo "<traefik-k8s-address> dev-hello-kubecon.juju.local" | sudo tee -a /etc/hosts

You should be able to visit http://dev-hello-kubecon.juju.local in your browser.

Testing

# Clone the charm code
$ git clone https://github.com/jnsgruk/hello-kubecon && cd hello-kubecon
# Install python3-virtualenv
$ sudo apt update && sudo apt install -y python3-virtualenv
# Create a virtualenv for the charm code
$ virtualenv venv
# Activate the venv
$ source ./venv/bin/activate
# Install dependencies
$ pip install -r requirements-dev.txt
# Run the tests
$ ./run_tests

Get Help & Community

If you get stuck deploying this charm, or would like help with charming generally, come and join the charming community!

More Information/Related

Below are some links related to this demonstration:

jnsgruk / hello-kubecon