Roles and ClusterRoles in Kubernetes - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a Role that allows reading pods in a namespace.

Kubernetes

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  namespace: default
  name: pod-reader
rules:
- apiGroups: [""]
  resources: ["pods"]
  verbs: ["[1]"]

Drag options to blanks, or click blank then click option'

Adelete

Bcreate

Cupdate

Dget

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'create' instead of 'get' will allow creating pods, not reading.

The verb get allows reading pod details in the namespace.

2fill in blank

medium

Complete the code to create a ClusterRole that allows listing all nodes.

Kubernetes

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: node-lister
rules:
- apiGroups: [""]
  resources: ["[1]"]
  verbs: ["list"]

Drag options to blanks, or click blank then click option'

Aservices

Bnodes

Cpods

Ddeployments

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing 'pods' will limit the role to pods, not nodes.

The resource nodes represents all nodes in the cluster, which ClusterRole can list.

3fill in blank

hard

Fix the error in the Role binding to bind the Role 'pod-reader' to user 'alice'.

Kubernetes

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: read-pods-binding
  namespace: default
subjects:
- kind: User
  name: alice
roleRef:
  kind: [1]
  name: pod-reader
  apiGroup: rbac.authorization.k8s.io

Drag options to blanks, or click blank then click option'

AClusterRole

BUser

CRole

DServiceAccount

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'ClusterRole' will cause the binding to fail if the role is a Role.

The roleRef.kind must match the kind of role being referenced. Here, it is a Role, not a ClusterRole.

4fill in blank

hard

Fill both blanks to create a ClusterRole that allows creating and deleting services.

Kubernetes

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: service-manager
rules:
- apiGroups: [""]
  resources: ["services"]
  verbs: ["[1]", "[2]"]

Drag options to blanks, or click blank then click option'

Acreate

Bget

Cdelete

Dlist

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'get' or 'list' only allows viewing, not creating or deleting.

The verbs create and delete allow managing services by adding and removing them.

5fill in blank

hard

Fill all three blanks to create a Role that allows updating deployments and listing pods in a namespace.

Kubernetes

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  namespace: production
  name: deploy-manager
rules:
- apiGroups: ["apps"]
  resources: ["[1]"]
  verbs: ["[2]"]
- apiGroups: [""]
  resources: ["[3]"]
  verbs: ["list"]

Drag options to blanks, or click blank then click option'

Adeployments

Bupdate

Cpods

Dcreate

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing 'create' with 'update' for modifying deployments.

This Role allows updating deployments in the 'apps' API group and listing pods in the core API group.

Practice

1. What is the main difference between a Role and a ClusterRole in Kubernetes?

easy

A. Role applies permissions within a single namespace, ClusterRole applies cluster-wide.

B. Role applies cluster-wide, ClusterRole applies within a single namespace.

C. Role is for users, ClusterRole is for service accounts only.

D. Role manages nodes, ClusterRole manages pods.

Solution

1. Step 1: Understand Role scope

   A Role defines permissions limited to a specific namespace in Kubernetes.

2. Step 2: Understand ClusterRole scope

   A ClusterRole defines permissions that can apply across all namespaces or cluster-wide resources.

3. Final Answer:

   Role applies permissions within a single namespace, ClusterRole applies cluster-wide. -> Option A

4. Quick Check:

   Role = namespace, ClusterRole = cluster-wide [OK]

Hint: Role = namespace only, ClusterRole = whole cluster [OK]

Common Mistakes:

• Confusing Role and ClusterRole scopes
• Thinking ClusterRole is only for nodes
• Assuming Role applies cluster-wide

2. Which of the following is the correct YAML snippet to create a Role that allows reading pods in a namespace?

easy

A. apiVersion: rbac.authorization.k8s.io/v1\nkind: Role\nmetadata:\n name: pod-reader\nrules:\n- apiGroups: ['']\n resources: ['pods']\n verbs: ['get', 'watch', 'list']

B. apiVersion: rbac.authorization.k8s.io/v1\nkind: ClusterRole\nmetadata:\n name: pod-reader\nrules:\n- apiGroups: ['']\n resources: ['pods']\n verbs: ['create', 'delete']

C. apiVersion: rbac.authorization.k8s.io/v1\nkind: RoleBinding\nmetadata:\n name: pod-reader-binding\nroleRef:\n kind: Role\n name: pod-reader\nsubjects:\n- kind: User\n name: alice

D. apiVersion: rbac.authorization.k8s.io/v1\nkind: Role\nmetadata:\n name: pod-reader\nrules:\n- apiGroups: ['apps']\n resources: ['pods']\n verbs: ['get', 'watch', 'list']

Solution

1. Step 1: Check kind and apiVersion

   The resource is a Role with apiVersion rbac.authorization.k8s.io/v1, which is correct for RBAC.

2. Step 2: Verify rules for reading pods

   Pods are in the core API group (empty string), and verbs for reading are get, watch, and list. apiVersion: rbac.authorization.k8s.io/v1\nkind: Role\nmetadata:\n name: pod-reader\nrules:\n- apiGroups: ['']\n resources: ['pods']\n verbs: ['get', 'watch', 'list'] matches this exactly.

3. Final Answer:

   The YAML snippet with kind: Role, apiGroups: [''], resources: ['pods'], verbs: ['get', 'watch', 'list']. -> Option A

4. Quick Check:

   Role + core API + read verbs = apiVersion: rbac.authorization.k8s.io/v1\nkind: Role\nmetadata:\n name: pod-reader\nrules:\n- apiGroups: ['']\n resources: ['pods']\n verbs: ['get', 'watch', 'list'] [OK]

Hint: Role for namespace, core API group is empty string [''] [OK]

Common Mistakes:

• Using ClusterRole instead of Role for namespace scope
• Wrong apiGroups value like 'apps' for pods
• Confusing RoleBinding with Role definition

3. Given this RoleBinding YAML snippet, what namespace will the binding apply to?

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: read-pods
  namespace: dev
roleRef:
  kind: Role
  name: pod-reader
  apiGroup: rbac.authorization.k8s.io
subjects:
- kind: User
  name: jane

medium

A. default namespace

B. Cluster-wide

C. kube-system namespace

D. dev namespace

Solution

1. Step 1: Check metadata namespace in RoleBinding

   The RoleBinding has namespace: dev in its metadata, so it applies in the 'dev' namespace.

2. Step 2: Understand RoleBinding scope

   RoleBindings are namespace-scoped, so they only apply in the namespace where they are created.

3. Final Answer:

   The RoleBinding applies to the dev namespace. -> Option D

4. Quick Check:

   RoleBinding namespace = binding scope [OK]

Hint: RoleBinding namespace field sets scope [OK]

Common Mistakes:

• Assuming RoleBinding applies cluster-wide
• Confusing RoleBinding with ClusterRoleBinding
• Ignoring the metadata namespace field

4. You created a ClusterRoleBinding but users report they cannot access cluster resources. Which is the most likely mistake?

medium

A. The subjects field is missing the user names.

B. The roleRef kind is set to Role instead of ClusterRole.

C. The ClusterRoleBinding is created in a namespace.

D. The apiVersion is set to v1 instead of rbac.authorization.k8s.io/v1.

Solution

1. Step 1: Check roleRef kind for ClusterRoleBinding

   A ClusterRoleBinding must reference a ClusterRole in its roleRef.kind. Using Role is invalid and prevents access.

2. Step 2: Verify other fields

   While missing subjects or wrong apiVersion cause issues, the most common cause is wrong roleRef.kind. ClusterRoleBindings are cluster-scoped and do not belong to namespaces.

3. Final Answer:

   The roleRef kind must be ClusterRole, not Role. -> Option B

4. Quick Check:

   ClusterRoleBinding needs ClusterRole in roleRef [OK]

Hint: ClusterRoleBinding must reference ClusterRole kind [OK]

Common Mistakes:

• Using Role instead of ClusterRole in roleRef
• Creating ClusterRoleBinding in a namespace
• Forgetting to specify subjects

5. You want to allow a user to list pods in all namespaces but only create pods in the 'test' namespace. Which combination of Kubernetes RBAC objects should you create?

hard

A. A ClusterRoleBinding granting create pods cluster-wide.

B. A single Role with both permissions in the 'test' namespace.

C. A ClusterRole with list pods permission and a Role with create pods permission, plus respective bindings.

D. A RoleBinding in 'test' namespace granting list and create pods.

Solution

1. Step 1: Understand permission scopes

   Listing pods in all namespaces requires a ClusterRole because it is cluster-wide permission.

2. Step 2: Restrict create pods to 'test' namespace

   Creating pods only in 'test' namespace requires a Role scoped to that namespace.

3. Step 3: Bind roles to user

   Use a ClusterRoleBinding for the cluster-wide list permission and a RoleBinding for the create permission in 'test'.

4. Final Answer:

   Create a ClusterRole for list pods and a Role for create pods with bindings. -> Option C

5. Quick Check:

   ClusterRole = cluster-wide, Role = namespace [OK]

Hint: Use ClusterRole for cluster-wide, Role for namespace-specific [OK]

Common Mistakes:

• Trying to use a single Role for cluster-wide permissions
• Using ClusterRoleBinding for namespace-only permissions
• Not creating separate bindings for each role