Path-based routing in Kubernetes - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

Output of path-based routing Ingress configuration

Given the following Kubernetes Ingress YAML snippet, what will be the backend service receiving traffic for the path /app1?

Kubernetes

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example-ingress
spec:
  rules:
  - http:
      paths:
      - path: /app1
        pathType: Prefix
        backend:
          service:
            name: service-app1
            port:
              number: 80
      - path: /app2
        pathType: Prefix
        backend:
          service:
            name: service-app2
            port:
              number: 80

A service-app1 on port 80

B service-app2 on port 80

C Default backend service

D No service, returns 404

💡 Hint

Look at the path and backend service mapping in the Ingress spec.

The path /app1 is explicitly routed to service-app1 on port 80 as per the Ingress rules.

❓ Configuration

intermediate

Correct pathType for prefix matching in Ingress

Which pathType value should be used in a Kubernetes Ingress to route all requests starting with /api to a backend service?

A Prefix

B Regex

C Exact

D ImplementationSpecific

💡 Hint

Consider which pathType matches all paths starting with the given prefix.

The 'Prefix' pathType matches all requests that start with the specified path prefix.

❓ Troubleshoot

advanced

Why does traffic to /app not route correctly?

A user configured this Ingress snippet but traffic to /app returns 404. What is the most likely cause?

Kubernetes

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: test-ingress
spec:
  rules:
  - http:
      paths:
      - path: /app/
        pathType: Exact
        backend:
          service:
            name: app-service
            port:
              number: 80

A Service app-service is not running

B Using pathType Exact with a trailing slash causes mismatch for /app

C Ingress controller is not installed

D Port 80 is blocked by firewall

💡 Hint

Check how Exact pathType matches requests.

Exact pathType requires the request path to exactly match /app/, so /app (without trailing slash) returns 404.

🔀 Workflow

advanced

Order of path matching in Kubernetes Ingress

In which order does Kubernetes Ingress controller evaluate multiple path rules for routing?

A 3,1,2,4

B 2,1,3,4

C 1,2,3,4

D 4,3,2,1

💡 Hint

Think about how more specific paths should be matched before less specific ones.

Ingress controllers match the longest path prefix first to ensure specific routes take precedence.

✅ Best Practice

expert

Best practice for path-based routing with overlapping paths

You have two Ingress paths: /app and /app/v2. What is the best practice to ensure traffic to /app/v2 goes to the correct backend without conflict?

A Use a single backend for both paths

B Use pathType Exact for both paths

C Use different Ingress resources for each path

D Define /app/v2 path before /app path in Ingress rules

💡 Hint

Consider how path matching order affects routing when paths overlap.

Defining the more specific path /app/v2 before /app ensures it matches first and routes correctly.

Practice

1. What does path-based routing in Kubernetes Ingress do?

easy

A. It sends traffic to different services based on URL paths.

B. It balances traffic evenly between all nodes.

C. It encrypts traffic between pods.

D. It schedules pods on specific nodes.

Solution

1. Step 1: Understand Ingress role

   Kubernetes Ingress manages external access to services, often HTTP.

2. Step 2: Identify path-based routing function

   Path-based routing directs requests to services depending on the URL path.

3. Final Answer:

   It sends traffic to different services based on URL paths. -> Option A

4. Quick Check:

   Path-based routing = directing traffic by URL path [OK]

Hint: Remember: path-based routing matches URL paths to services [OK]

Common Mistakes:

• Confusing path-based routing with load balancing
• Thinking it schedules pods
• Assuming it encrypts traffic

2. Which is the correct way to specify a path in a Kubernetes Ingress rule for path-based routing?

easy

A. url: /app
urlType: Prefix

B. route: /app
routeType: Exact

C. servicePath: /app
serviceType: Exact

D. path: /app
pathType: Prefix

Solution

1. Step 1: Recall Ingress rule syntax

   Ingress rules use path and pathType keys to define routing.

2. Step 2: Match correct keys and values

   Correct keys are path and pathType, with values like '/app' and 'Prefix'.

3. Final Answer:

   path: /app pathType: Prefix -> Option D

4. Quick Check:

   Use path and pathType keys for routing [OK]

Hint: Look for 'path' and 'pathType' keys in Ingress rules [OK]

Common Mistakes:

• Using wrong keys like 'route' or 'url'
• Mixing up pathType values
• Missing pathType field

3. Given this Ingress snippet, which service will receive traffic for URL path '/shop/cart'?

rules:
- http:
    paths:
    - path: /shop
      pathType: Prefix
      backend:
        service:
          name: shop-service
          port:
            number: 80
    - path: /blog
      pathType: Prefix
      backend:
        service:
          name: blog-service
          port:
            number: 80

medium

A. blog-service

B. shop-service

C. default backend

D. No service matches

Solution

1. Step 1: Check path matching rules

   Path '/shop/cart' starts with '/shop', matching the first path rule with pathType Prefix.

2. Step 2: Identify backend service

   The matching path routes to 'shop-service' on port 80.

3. Final Answer:

   shop-service -> Option B

4. Quick Check:

   Prefix match '/shop' routes to shop-service [OK]

Hint: Prefix path matches any URL starting with it [OK]

Common Mistakes:

• Choosing blog-service for /shop/cart
• Assuming no match for subpaths
• Confusing default backend with path rules

4. You wrote this Ingress rule but traffic to '/api' is not routed correctly:

paths:
- path: api
  pathType: Prefix
  backend:
    service:
      name: api-service
      port:
        number: 80

What is the likely error?

medium

A. Incorrect pathType value

B. Service name is invalid

C. Missing leading slash in path value

D. Port number must be a string

Solution

1. Step 1: Check path syntax

   Paths must start with a leading slash '/' to match URLs correctly.

2. Step 2: Identify missing slash

   The path is 'api' instead of '/api', so it won't match requests starting with '/api'.

3. Final Answer:

   Missing leading slash in path value -> Option C

4. Quick Check:

   Paths need leading '/' for correct matching [OK]

Hint: Always start path with '/' in Ingress rules [OK]

Common Mistakes:

• Omitting leading slash in path
• Using wrong pathType values
• Assuming port number must be string

5. You want to route traffic so that: - '/app' goes to 'app-service' - '/app/admin' goes to 'admin-service' Which Ingress path rules correctly implement this path-based routing?

hard

A. - path: /app/admin
pathType: Prefix
backend:
service:
name: admin-service
port:
number: 80
- path: /app
pathType: Prefix
backend:
service:
name: app-service
port:
number: 80

B. - path: /app
pathType: Prefix
backend:
service:
name: app-service
port:
number: 80
- path: /app/admin
pathType: Prefix
backend:
service:
name: admin-service
port:
number: 80

C. - path: /app
pathType: Exact
backend:
service:
name: app-service
port:
number: 80
- path: /app/admin
pathType: Exact
backend:
service:
name: admin-service
port:
number: 80

D. - path: /app/admin
pathType: Exact
backend:
service:
name: admin-service
port:
number: 80
- path: /app
pathType: Exact
backend:
service:
name: app-service
port:
number: 80

Solution

1. Step 1: Understand path matching order

   Ingress matches paths in order; more specific paths must come first to avoid being shadowed.

2. Step 2: Check rule order and pathType

   Placing '/app/admin' before '/app' with pathType Prefix ensures '/app/admin' routes to admin-service, others to app-service.

3. Final Answer:

   Place '/app/admin' rule before '/app' rule with Prefix pathType -> Option A

4. Quick Check:

   Order specific paths first for correct routing [OK]

Hint: List longer paths before shorter ones in Ingress rules [OK]

Common Mistakes:

• Placing general path before specific path
• Using Exact pathType causing no subpath matches
• Ignoring rule order importance