Notary is a service that signs docker images. For sercurity this can be useful as it can establish integrity within your running cluster and enforce rules that only allow signed images to run.
More information around Notary https://docs.docker.com/notary/getting_started/
Update notary/server-deployment.yaml with a custom image that contains certificates for signing the images.
kubectl apply -f notary-k8s/. -n yournamespacehere