Profile applicability: Level 1 - Master Node
Use individual service account credentials for each controller.
The controller manager creates a service account per controller in the
kube-system namespace, generates a credential for it, and builds a dedicated API client with
that service account credential for each controller loop to use. Setting the --use-service-account-credentials to true runs each control loop within the controller manager using a separate service account
credential. When used in combination with RBAC, this ensures that the control loops
run with the minimum permissions required to perform their intended tasks.
NoteBy default,
--use-service-account-credentials is set to false. |
Impact
Whatever authorizer is configured for the cluster, it must grant sufficient permissions
to the service accounts to perform their intended tasks. When using the RBAC authorizer,
those roles are created and bound to the appropriate service accounts in the
kube-system namespace automatically with default roles and rolebindings that are auto- reconciled
on startup.If using other authorization methods (ABAC, Webhook, etc), the cluster deployer is
responsible for granting appropriate permissions to the service accounts (the required
permissions can be seen by inspecting the
controller-roles.yaml and controller-role-bindings.yaml files for the RBAC roles.Audit
Run the following command on the Control Plane node:
ps -ef | grep kube-controller-manager
Verify that the
--use-service-account-credentials argument is set to true.Remediation
Edit the Controller Manager pod specification file
/etc/kubernetes/manifests/kube-controller-manager.yaml on the Control Plane node to set the below parameter.--use-service-account-credentials=true
