You should make sure your API server supports Mutating Webhooks.
Its --admission-control flag should have MutatingAdmissionWebhook as one of
the values on the list and its --runtime-config flag should include
admissionregistration.k8s.io/v1beta1=true.
Generate certs by running bash gencerts.sh. This will use kubectl to create
a secret in your cluster with the certs.
Create RBAC configuration for the admission controller pod by running
kubectl create -f ../deploy/admission-controller-rbac.yaml
Create the pod:
kubectl cerate -f ../deploy/admission-controlller-deployment.yaml.
The first thing this will do is it will register itself with the apiserver as
an Webhook Admission Controller and start changing resource requirements
for pods on their creation & updates.