I cannot find any articles answering question: Is it safe/right to deploy Spinnaker to same Kubernetes cluster which Spinnaker will manage? Mainly I mean for production, HA deployments.
I'm not sure about "right", but I'd definitely say that it is safe to run Spinnaker on the same Kubernetes cluster that it manages, if you set it up right. Kubernetes (and Docker) gives you all the tools you need to properly separate Spinnaker from the other things running on the cluster (namespaces, quotas, node affinities etc). Indeed the whole point of Kubernetes is to be able to easily run software in an HA/fault tolerant way, and since Spinnaker consists of a collection of stateless microservices it really plays to the strenghts of k8s.
I think the architectures of Spinnaker and Kubernetes compliment each other very well, and running Spinnaker in the same K8s cluster it is managing is definitely safe.
As per your comment in @mdirkse's answer, there is a codelab, which is official Spinnaker documentation, that explains how to create a set of basic pipelines for deploying code from a Github repo to a production Kubernetes cluster in the form of a Docker container.
In this documentation, it specifically states the following:
We will be deploying Spinnaker to the same Kubernetes cluster it will be managing. ...
Not sure if this is exactly what you are looking for though.