Kubernetes is the go-to platform for production grid applications.
The hosts themselves must be secured:
Password-based authentication is disabled.
Only ssh key-based authentication is enabled.
Other physical security considerations.
The kube-apiserver is the centre of all operations with Kubernetes.
Can interact it with the kubectl utility or through accessing the API directly.
First line of defence is controlling any access to the kube-apiserver itself.
Who can access the cluster?
What can they do?
Who can access?
Files - Usernames and Passwords
Files - Username and Token
Certificates
External Authentication Providers - LDAP
Service Accounts
What can the users when accessing the cluster via the above methods do?
RBAC Authorisation - users assigned to specific groups with X permissions.
ABAC Authorisation (Attribute Based Access Control).
Node Authorisation
Webhook Mode
All communication within the cluster, such as with the ETCD cluster, Kubelet (worker node), Kube Proxy (worker node), Kube Scheduler and Kube Controller Manager is done using TLS encryption and certificates.
How about communication between applications within the cluster - by default all applications can access each other in the cluster.
Can restrict access between them using network policies.