I am currently working with a Hyperledger Fabric v1.4 deployment over k8s. The chaincode containers that are generated are basically create by the container running within the peer pods and k8s as such has no knowledge and control of the chaincode containers. In such a scenario where there is a Docker container running along with k8s and k8s has no knowledge of a particular docker container, is it possible for the Docker container to in some way gain access to the k8s master API and gain access to the whole k8s cluster consequently?
My intention with asking this question is to figure out if there is a way to use an container external to any pods in k8s, to cause any undesirable impact to the k8s cluster by gaining unauthorized access to k8s. The chaincode container that I talked about, is created using a trusted template image and the only possible malicious component in the container is a single golang, java or nodejs script that is provided by the user. So my real question here is, "Is it possible using these user scripts gain unauthorized access to the k8s cluster?" And I am primarily focusing on a manager k8s service like Azure Kubernetes Service.
Your question totally changed the meaning so I'll try to rewrite the answer.
You have to remember that the pod you are running the code on by default is limited to just the namespace it's running on. If you didn't gave it any higher privileges. Also the code is not running as root.
You can read about Pod Security Policies and Configure a Security Context for a Pod or Container.
TLDR. As long as you don't give it any special privileges or rights it should be fairly save for your cluster.