189-metacontroller.sh

# Source: https://gist.github.com/8adaf8fd6496bc99a466ba55834e1838

###############################################################
# Metacontroller - Custom Kubernetes Controllers The Easy Way #
# https://youtu.be/3xkLYOpXy2U                                #
###############################################################

# Additional Info:
# - Metacontroller: https://metacontroller.github.io/metacontroller
# - DevOps MUST Build Internal Developer Platform (IDP): https://youtu.be/j5i00z3QXyU
# - Crossplane - GitOps-based Infrastructure as Code through Kubernetes API: https://youtu.be/n8KjVmuHm7A
# - Terraform vs. Pulumi vs. Crossplane - Infrastructure as Code (IaC) Tools Comparison: https://youtu.be/RaoKcJGchKM
# - How To Apply GitOps To Everything - Combining Argo CD And Crossplane: https://youtu.be/yrj4lmScKHQ
# - How To Shift Left Infrastructure Management Using Crossplane Compositions: https://youtu.be/AtbS1u2j7po
# - Cloud-Native Apps With Open Application Model (OAM) And KubeVela: https://youtu.be/2CBu6sOTtwk
# - Combining Argo CD (GitOps), Crossplane (Control Plane), And KubeVela (OAM): https://youtu.be/eEcgn_gU3SM
# - Should We Replace Docker Desktop With Rancher Desktop?: https://youtu.be/bYVfCp9dRTE

#########
# Setup #
#########

git clone https://github.com/vfarcic/metacontroller-demo

cd metacontroller-demo

# Create a Kubernetes cluster with Ingress controller enabled and set as default.
# This demo was tested on Rancher Desktop, but it should work with any Kubernetes cluster
# Please watch https://youtu.be/bYVfCp9dRTE if you are not familiar with Rancher Desktop

# Replace `127.0.0.1` with the Ingress Service IP if not using kind
export INGRESS_HOST=127.0.0.1

kubectl apply \
    --kustomize https://github.com/metacontroller/metacontroller/manifests/production

kubectl create namespace production

kubectl create namespace controllers

# Install `yq` from https://github.com/mikefarah/yq if you do not have it already

yq --inplace \
    ".spec.host = \"silly-demo.$INGRESS_HOST.nip.io\"" \
    my-app.yaml

yq --inplace \
    ".spec.host = \"silly-demo.$INGRESS_HOST.nip.io\"" \
    my-app-1-0-7.yaml

#################################################
# Kubernetes Custom Resource Definitions (CRDs) #
#################################################

cat crds.yaml

kubectl apply --filename crds.yaml

kubectl get crds

kubectl explain apps --recursive

cat slack.yaml

kubectl apply --filename slack.yaml

kubectl get slacks

cat my-app.yaml

kubectl --namespace production apply \
    --filename my-app.yaml

kubectl --namespace production \
    get apps

kubectl --namespace production delete \
    --filename my-app.yaml

#################################
# Custom Kubernetes Controllers #
#################################

cat composite-controllers.yaml

kubectl apply \
    --filename composite-controllers.yaml

kubectl get compositecontrollers

cat main.go

cat app.py

kubectl --namespace controllers \
    create configmap app \
    --from-file=app.py

cat controllers.yaml

kubectl --namespace controllers apply \
    --filename controllers.yaml

############################
# Metacontroller In Action #
############################

cat my-app.yaml

kubectl --namespace production apply \
    --filename my-app.yaml

kubectl --namespace controllers logs \
    --selector app=slack-controller

kubectl --namespace production \
    get apps

kubectl --namespace production \
    get all,ingresses

diff my-app.yaml my-app-1-0-7.yaml

kubectl --namespace production apply \
    --filename my-app-1-0-7.yaml

kubectl --namespace production \
    get all,ingresses

curl "http://silly-demo.$INGRESS_HOST.nip.io"

kubectl --namespace production delete \
    --filename my-app-1-0-7.yaml

kubectl --namespace production \
    get all,ingresses

###########
# Destroy #
###########

# Destroy or reset the Kubernetes cluster

# ... or ...

kubectl delete \
    --filename composite-controllers.yaml

kubectl delete --filename slack.yaml

kubectl delete --filename crds.yaml

kubectl delete ns controllers

kubectl delete ns metacontroller

kubectl delete ns production