Namespace isolation in Microservices - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a namespace for service isolation.

Microservices

apiVersion: v1
kind: Namespace
metadata:
  name: [1]

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

Adefault

Bkube-system

Cpublic

Duser-service

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'default' namespace which does not isolate services.

The namespace name should be unique to isolate the user-service.

2fill in blank

medium

Complete the code to select pods within a specific namespace.

Microservices

kubectl get pods -n [1]

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

Adefault

Ball

Cuser-service

Dkube-system

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'default' or 'all' which do not target the specific namespace.

To list pods in the user-service namespace, use '-n user-service'.

3fill in blank

hard

Fix the error in the YAML to isolate services by namespace.

Microservices

apiVersion: v1
kind: Service
metadata:
  name: payment-service
  namespace: [1]

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

Akube-system

Bpayment-namespace

Cdefault

Dpayment-service

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'default' or 'kube-system' namespaces incorrectly.

The namespace field must match the namespace where the service is deployed, here 'payment-namespace'.

4fill in blank

hard

Fill both blanks to create a network policy that isolates traffic within a namespace.

Microservices

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-internal
  namespace: [1]
spec:
  podSelector: {}
  policyTypes:
  - Ingress
  ingress:
  - from:
    - podSelector: [2]

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

Apayment-namespace

B{}

Cuser-service

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Using podSelector 'null' or a different namespace name.

The network policy applies to 'payment-namespace' and allows ingress from all pods (empty podSelector {}).

5fill in blank

hard

Fill all three blanks to define resource quotas for CPU and memory in a namespace.

Microservices

apiVersion: v1
kind: ResourceQuota
metadata:
  name: compute-resources
  namespace: [1]
spec:
  hard:
    requests.cpu: [2]
    requests.memory: [3]

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

Auser-service

B4

C8Gi

Ddefault

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'default' namespace or incorrect resource values.

The resource quota is set for the 'user-service' namespace with CPU requests limited to 4 cores and memory to 8Gi.

Practice

1. What is the main purpose of namespace isolation in microservices architecture?

easy

A. To merge all microservices into a single unit

B. To group related microservices and resources to avoid conflicts

C. To increase the size of each microservice

D. To reduce the number of microservices in the system

Solution

1. Step 1: Understand the role of namespaces

   Namespaces group related microservices and their resources to keep them organized and separate.

2. Step 2: Identify the benefit of isolation

   Isolation prevents conflicts between services and helps manage different environments or teams.

3. Final Answer:

   To group related microservices and resources to avoid conflicts -> Option B

4. Quick Check:

   Namespace isolation = grouping and conflict prevention [OK]

Hint: Namespaces group services to avoid conflicts [OK]

Common Mistakes:

• Thinking namespaces merge microservices
• Believing namespaces reduce microservice count
• Confusing namespaces with scaling techniques

2. Which of the following is the correct way to define a namespace in Kubernetes YAML for microservices?

easy

A. apiVersion: v1\nkind: Namespace\nmetadata:\n name: my-namespace

B. apiVersion: v1\nkind: Service\nmetadata:\n name: my-namespace

C. apiVersion: v1\nkind: Pod\nmetadata:\n namespace: my-namespace

D. apiVersion: v1\nkind: Deployment\nmetadata:\n name: my-namespace

Solution

1. Step 1: Identify the resource type for namespaces

   Namespaces in Kubernetes are defined with kind: Namespace.

2. Step 2: Check the YAML structure

   The YAML must have apiVersion: v1, kind: Namespace, and metadata.name set to the namespace name.

3. Final Answer:

   apiVersion: v1 kind: Namespace metadata: name: my-namespace -> Option A

4. Quick Check:

   Namespace YAML uses kind Namespace [OK]

Hint: Namespace YAML uses kind: Namespace and metadata.name [OK]

Common Mistakes:

• Using kind: Service or Deployment instead of Namespace
• Placing namespace under metadata.namespace instead of metadata.name
• Confusing Pod namespace with Namespace resource

3. Given the following Kubernetes setup, what namespace will the pod belong to if no namespace is specified in the pod YAML?

apiVersion: v1
kind: Pod
metadata:
  name: example-pod
spec:
  containers:
  - name: app
    image: nginx

medium

A. example-pod

B. kube-system

C. default

D. No namespace assigned

Solution

1. Step 1: Understand Kubernetes default behavior

   If no namespace is specified, Kubernetes assigns the resource to the default namespace automatically.

2. Step 2: Confirm pod YAML lacks namespace field

   The pod YAML does not specify metadata.namespace, so it uses the default namespace.

3. Final Answer:

   default -> Option C

4. Quick Check:

   Missing namespace means default namespace used [OK]

Hint: No namespace specified means default namespace [OK]

Common Mistakes:

• Assuming pod gets a namespace named after pod
• Thinking kube-system is default for all pods
• Believing pod has no namespace if not specified

4. You have two microservices with the same name deployed in different namespaces but they are conflicting. What is the most likely cause?

medium

A. Namespaces are not properly isolated or DNS is misconfigured

B. Microservices must have unique names across all namespaces

C. Namespaces merge services with the same name automatically

D. The microservices are deployed in the same namespace

Solution

1. Step 1: Understand namespace isolation purpose

   Namespaces isolate services so same names can coexist without conflict.

2. Step 2: Identify cause of conflict

   If conflict occurs, likely isolation is broken or DNS resolving services ignores namespaces.

3. Final Answer:

   Namespaces are not properly isolated or DNS is misconfigured -> Option A

4. Quick Check:

   Conflict with same names means isolation or DNS issue [OK]

Hint: Conflicts mean isolation or DNS setup problem [OK]

Common Mistakes:

• Assuming service names must be unique globally
• Believing namespaces merge services automatically
• Ignoring DNS configuration in microservice discovery

5. You want to deploy multiple versions of a microservice for different teams using namespace isolation. Which approach best supports scalability and fault isolation?

hard

A. Merge all microservices into one namespace and use version numbers in URLs

B. Deploy all versions in the same namespace with different service names

C. Use a single namespace and tag microservices with team labels

D. Create separate namespaces per team and deploy microservices with same names inside each

Solution

1. Step 1: Analyze namespace isolation benefits

   Namespaces isolate resources, allowing same service names in different namespaces without conflict.

2. Step 2: Evaluate scalability and fault isolation

   Separate namespaces per team isolate faults and scale independently, improving management and security.

3. Step 3: Compare other options

   Same namespace with different names or labels reduces isolation and complicates management.

4. Final Answer:

   Create separate namespaces per team and deploy microservices with same names inside each -> Option D

5. Quick Check:

   Separate namespaces per team = best isolation and scalability [OK]

Hint: Use separate namespaces per team for isolation and scaling [OK]

Common Mistakes:

• Using one namespace with labels only
• Changing service names instead of namespaces
• Merging all versions in one namespace