Override k8s version for k3d

General MR

Summary

This allows for overriding the K3S tag in K3D to be able to use a different K8S version. This is occasionally something required when trying to reproduce an error or even test on a future version of K8S (K3D determines which version of K3S they want to use).

Relevant logs/screenshots

N/A

docs/assets/scripts/developer/k3d-dev.sh

@@ -372,7 +372,7 @@ echo
 echo "Installing k3d on instance"
 run "wget -q -O - https://raw.githubusercontent.com/rancher/k3d/main/install.sh | TAG=v5.4.9 bash"
 echo
-echo "k3d version"
+echo "k3d default Kubernetes version"
 run "k3d version"
 echo
 
@@ -388,6 +388,12 @@ k3d_command+=" --k3s-arg \"--disable=traefik@server:0\"  --k3s-arg \"--disable=m
 # Port mappings to support Istio ingress + API access
 k3d_command+=" --port 80:80@loadbalancer --port 443:443@loadbalancer --api-port 6443"
 
+K3S_IMAGE_TAG=${K3S_IMAGE_TAG:=""}
+if [[ ! -z "$K3S_IMAGE_TAG" ]]; then
+  echo "Using custom K3S image tag $K3S_IMAGE_TAG..."
+  k3d_command+=" --image docker.io/rancher/k3s:$K3S_IMAGE_TAG"
+fi
+
 # Add MetalLB specific k3d config
 if [[ "$METAL_LB" == true ]]; then
   # create docker network for k3d cluster