Kubernetes is a wildly extensible, configurable, enterprise grade orchestration platform which drives many of the largest presences on the web.

Advantages of Kubernetes

Extensibility

Each site runs whatever servers, configs, and apps needed in its own container

Containers can all share an IP via Ingress routing

Scalability

Increasing the number of replicas for a deployment is a one line change

If host resources are running low, more nodes can be added to the cluster

Automation

Automated LetsEncrypt certificate provisioning and updates

Resilience

Containers are automatically restarted in case of failure

Experience

Setting up static sites is a relatively easy way to get experience with Kubernetes

MicroK8s

Addons

Easily add common applications to your Kubernetes cluster

Automatic Updates

The MicroK8s snap package will automatically update for minor version releases

CNCF Compliant

Guarantees standard open source Kubernetes software stack

Ensures expected, versioned API compatibility

Simplicity

Easy to install, no special configuration needed

MicroK8s Installation

# Install snapd
sudo apt install snapd

# Install the latest microk8s snap
# (can be made explicit with --channel=latest/stable
# or use specific channel from `snap info microk8s`)
sudo snap install microk8s --classic

# Add your user to the microk8s group
usermod -a G microk8s $USER
newgrp microk8s

MicroK8s Configuration

# Check MicroK8s status and list available/enabled addons
microk8s status

# Install the ingress and cert-manager addons
microk8s enable ingress cert-manager

Put a simple site in an nginx container

Or any container, but if you want transparent logging, redirect to stdout and stderr, which the default nginx container does for you!

FROM nginx
COPY html /usr/share/nginx/html

Build and tag your docker image with a fake registry for sideloading:

# build / tag
sudo docker build -t \
  microk8s.sideload/seagl00.k8s.jp.net:v000 seagl00/

# sideload import to microk8s
sudo docker save microk8s.sideload/seagl00.k8s.jp.net:v000 |\
  microk8s image import

# list images
microk8s ctr images list

Edit some yaml and apply!

Grab example yamls from the example repo

microk8s kubectl apply -f ./seagl00.yaml
microk8s kubectl apply -f ./seagl01.yaml
microk8s kubectl apply -f ./ingress.yaml

Same command with replace instead of apply for updates!

Thanks

Slides:

[JS seagl2023.slides.k8s.jp.net]

[PDF talk.jpnc.info/k8s-simple-sites.jpnc.seagl2023.pdf]

Example code:

git.jpnc.info/simple_sites.k8s.examples/tree/seagl2023

Example sites:

seagl00.k8s.jp.net       seagl01.k8s.jp.net

Find me at jpnc.info