CREATE-CIVO.md

k3d Setup for Linkerd and Cert-Manager in Production Workshop

This is the documentation - and executable code! - for creating a simple k3d cluster for the Service Mesh Academy the "Linkerd and Cert-Manager in Production" workshop. The easiest way to use this file is to execute it with demosh.

Things in Markdown comments are safe to ignore when reading this later. When executing this with demosh, things after the horizontal rule below (which is just before a commented @SHOW directive) will get displayed.

We'll do nothing at all if there's already cluster named pki.

set -e
DEMOSH_QUIET_FAILURE=true

if kubectl --context pki config get-contexts pki >/dev/null 2>&1; then \
    echo "Cluster 'pki' already exists" >&2 ;\
    exit 1 ;\
fi

---

The Linkerd and Cert-Manager in Production workshop can use pretty much any kind of cluster, but using a Civo cluster for it can sometimes be convenient. Here, we'll set up the one cluster that we need, but we won't install anything yet.

First up, we need to make absolutely certain that there's no context, cluster, or user named pki in our KUBECONFIG. This is working around a bug in the Civo CLI.

kubectl config delete-context pki || true
kubectl config delete-cluster pki || true
kubectl config delete-user pki || true

THEN we can use civo k8s create to create a new pki cluster. The only weird bit here is that we're deliberately not installing Traefik (we don't need it, so whatever).

civo k8s create pki --save --merge --remove-applications Traefik-v2-nodeport --wait

After that, make sure the new context is current...

kubectx pki

...and then wait until the cluster has some running pods. The kubectl command in the loop will give [] when no pods exist, so any result with more than 2 characters in it indicates that some pods exist. (This is obviously a pretty basic check, but it's the way to do this without needing jq or the like.)

while true; do \
    count=$(kubectl get pods -n kube-system -l k8s-app=kube-dns -o jsonpath='{ .items }' | wc -c) ;\
    if [ $count -gt 2 ]; then break; fi ;\
done

Finally, wait for the kube-dns Pod to be ready. (This is the reason that the previous loop is there: trying to wait for a Pod that doesn't yet exist will throw an error.)

kubectl wait pod --for=condition=ready \
        --namespace=kube-system --selector=k8s-app=kube-dns \
        --timeout=1m

Done! The pki cluster should be ready for the rest of the workshop.