istioctl install -f k8s/istio/istiooperator.yml

This above command installs Istio using the configuration specified in the istiooperator.yml file located in the k8s/istio directory.

kubectl label namespace default istio-injection=enabled

This above command enables automatic sidecar injection for the default namespace, allowing Istio to manage traffic within that namespace.

kubectl get crd gateways.gateway.networking.k8s.io &> /dev/null || \
  kubectl apply -f https://github.com/kubernetes-sigs/gateway-api/releases/download/v1.3.0/standard-install.yaml

This above command checks if the gateways.gateway.networking.k8s.io Custom Resource Definition (CRD) exists. If it does not, it applies the standard installation of the Gateway API from the specified URL. This is useful for managing ingress traffic in Kubernetes clusters. Run it before deploying the Istio gateway.

kubectl -n ingress-nginx get deploy ingress-nginx-controller -o yaml | istioctl kube-inject -f - | kubectl apply -f -

This above command injects the Istio sidecar into the ingress-nginx-controller deployment in the ingress-nginx