kubernetes-sigs/cluster-api

Minimize RBAC roles for controllers

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#6,554 opened on May 26, 2022

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Description

Following on from #https://github.com/kubernetes-sigs/cluster-api/pull/6510#discussion_r882538225

In Cluster API today we create RBAC manifests which are generated using kubebuilder tools. e.g.

https://github.com/kubernetes-sigs/cluster-api/blob/626ab4de03ef1e8f9b68e12bbfaf75e2cb0b4ffc/internal/controllers/clusterclass/clusterclass_controller.go#L42-L44

Many of our controllers seem to generate overly broad RBAC for themselves. e.g. many have the create verb when it is not used. Removing these roles should have no impact on functitonality, minimize the capabilities of our controllers from a security perspective, and make our RBAC manifests more descriptive about what our controllers are actually doing.

We should audit the following controllers to minimize their RBAC roles:

  • MachineHealthCheck
  • Machinepool
  • KubeadmConfig
  • ClusterResourceSet
  • Cluster
  • Machine
  • MachineDeployment
  • MachineSet
  • Topology/Cluster
  • ClusterClass

Contributor guide

Research direction
Audit each listed controller's RBAC markers in the codebase. For each controller, identify the RBAC permissions (especially create, update, delete verbs) and compare with actual usage. Remove any unnecessary permissions. Use the kubebuilder annotations to modify the RBAC manifests.
Tech stack
go
Domain
backendsecurity
Issue type
Chore
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
3-5 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
GoKubernetes RBACGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
65