TLS termination with Ingress in Kubernetes - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is TLS termination in the context of Kubernetes Ingress?

TLS termination means the Ingress controller handles decrypting HTTPS traffic, so the backend services receive plain HTTP traffic.

beginner

Which Kubernetes resource is used to configure TLS certificates for Ingress?

A Kubernetes Secret of type 'tls' stores the TLS certificate and private key used by the Ingress for TLS termination.

intermediate

How do you specify TLS settings in an Ingress manifest?

You add a 'tls' section listing the hosts and the secretName that contains the TLS certificate.

intermediate

Why is TLS termination at Ingress useful in Kubernetes?

It centralizes HTTPS handling, reduces load on backend services, and simplifies certificate management.

advanced

What happens if the TLS secret referenced in the Ingress does not exist?

The Ingress controller cannot terminate TLS, so HTTPS connections will fail or fallback to HTTP depending on configuration.

What Kubernetes object stores the TLS certificate for Ingress TLS termination?

A Pod

B Secret

C ConfigMap

D Service

TLS certificates are stored in Secrets of type 'tls' for secure handling.

Where is TLS termination performed when using Ingress in Kubernetes?

A At the Ingress controller

B At the backend service

C At the Pod level

D At the Node level

Ingress controller handles TLS termination, decrypting HTTPS traffic before forwarding.

Which field in the Ingress manifest specifies the TLS secret?

A metadata.name

B spec.backend.serviceName

C spec.rules.host

D spec.tls.secretName

The 'secretName' under 'spec.tls' points to the TLS secret.

What protocol does the Ingress controller use to communicate with backend services after TLS termination?

A FTP

B HTTPS

C HTTP

D SSH

After TLS termination, traffic is usually forwarded as plain HTTP to backend services.

If you want to enable HTTPS for multiple domains in Ingress, what should you do?

A List all domains under spec.tls.hosts with the same secret

B Create separate Ingress for each domain without TLS

C Use ConfigMap to store certificates

D Use NodePort service type

You list all domains in the 'hosts' array under 'spec.tls' using the same TLS secret.

Explain how TLS termination works with Kubernetes Ingress and why it is beneficial.

Think about where encryption ends and how it affects backend services.

Describe the steps to configure TLS termination in a Kubernetes Ingress resource.

Focus on secret creation and Ingress manifest changes.

Practice

1. What is the main purpose of TLS termination in a Kubernetes Ingress?

easy

A. To monitor network traffic for security threats

B. To encrypt traffic between backend services

C. To generate TLS certificates automatically

D. To decrypt HTTPS traffic at the Ingress before forwarding to backend services

Solution

1. Step 1: Understand TLS termination role

   TLS termination means decrypting encrypted HTTPS traffic at a central point.

2. Step 2: Identify Ingress function

   Kubernetes Ingress can handle TLS termination by decrypting traffic before sending it to backend pods.

3. Final Answer:

   To decrypt HTTPS traffic at the Ingress before forwarding to backend services -> Option D

4. Quick Check:

   TLS termination = decrypt at Ingress [OK]

Hint: TLS termination means decrypting at Ingress, not backend [OK]

Common Mistakes:

• Confusing TLS termination with encryption between services
• Thinking Ingress generates certificates automatically
• Assuming TLS termination monitors traffic

2. Which of the following is the correct way to specify TLS in a Kubernetes Ingress YAML?

easy

A. tls:
- hosts:
- example.com
secret: tls-secret

B. tls:
- hosts:
- example.com
secretName: tls-secret

C. tls:
- host: example.com
secret: tls-secret

D. tls:
hosts: example.com
secretName: tls-secret

Solution

1. Step 1: Review TLS section syntax

   The correct syntax uses a list under tls with hosts as a list and secretName key.

2. Step 2: Compare options

   tls: - hosts: - example.com secretName: tls-secret matches the correct YAML structure with 'secretName' and hosts list.

3. Final Answer:

   tls: - hosts: - example.com secretName: tls-secret -> Option B

4. Quick Check:

   Correct TLS YAML uses secretName and hosts list [OK]

Hint: Use 'secretName' and list under 'hosts' in tls section [OK]

Common Mistakes:

• Using 'secret' instead of 'secretName'
• Not using a list for hosts
• Incorrect indentation or missing dash

3. Given this Ingress snippet:

tls:
  - hosts:
    - myapp.example.com
    secretName: myapp-tls

rules:
  - host: myapp.example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: myapp-service
            port:
              number: 80

What happens when a user accesses https://myapp.example.com?

medium

A. The Ingress decrypts TLS and forwards HTTP traffic to myapp-service on port 80

B. The Ingress forwards encrypted TLS traffic directly to myapp-service

C. The Ingress rejects the connection because backend port is 80

D. The Ingress terminates TLS but forwards HTTPS traffic to backend

Solution

1. Step 1: Understand TLS termination in Ingress

   The Ingress uses the secret to decrypt HTTPS traffic for the host.

2. Step 2: Check backend service port and protocol

   The backend service listens on port 80 (HTTP), so decrypted HTTP traffic is forwarded.

3. Final Answer:

   The Ingress decrypts TLS and forwards HTTP traffic to myapp-service on port 80 -> Option A

4. Quick Check:

   Ingress decrypts TLS, backend gets HTTP [OK]

Hint: Ingress decrypts TLS, backend usually gets HTTP on port 80 [OK]

Common Mistakes:

• Assuming backend receives encrypted traffic
• Thinking backend must use HTTPS port
• Confusing TLS termination with passthrough

4. You configured TLS in your Ingress but HTTPS requests fail with a certificate error. What is the most likely cause?

medium

A. The secret referenced in tls section does not contain a valid TLS certificate

B. The backend service is not listening on port 443

C. The Ingress controller does not support TLS termination

D. The Ingress resource is missing the rules section

Solution

1. Step 1: Check TLS secret validity

   If the secret does not have a valid TLS cert and key, HTTPS will fail with certificate errors.

2. Step 2: Verify other options

   Backend port or missing rules do not cause cert errors; controller usually supports TLS.

3. Final Answer:

   The secret referenced in tls section does not contain a valid TLS certificate -> Option A

4. Quick Check:

   Invalid TLS secret = cert error [OK]

Hint: Check TLS secret contents first for certificate errors [OK]

Common Mistakes:

• Blaming backend port for TLS cert errors
• Assuming Ingress controller lacks TLS support
• Ignoring TLS secret correctness

5. You want to secure multiple domains with TLS termination using a single Ingress resource. Which approach is correct?

hard

A. Use one tls entry with multiple hosts but different secrets for each host

B. Create separate Ingress resources for each domain with their own TLS secrets

C. Add multiple entries under the tls section with hosts and a single secret containing SAN certificates

D. Configure TLS only on backend services, not on Ingress

Solution

1. Step 1: Understand TLS with multiple hosts

   A single secret can contain a certificate with multiple Subject Alternative Names (SANs) for multiple domains.

2. Step 2: Configure Ingress tls section

   The tls field is a list, so add multiple entries under tls, each with a hosts list and referencing the same secretName containing the SAN cert.

3. Final Answer:

   Add multiple entries under the tls section with hosts and a single secret containing SAN certificates -> Option C

4. Quick Check:

   Multiple tls entries share SAN secret [OK]

Hint: Multiple tls entries can share one SAN cert secret [OK]

Common Mistakes:

• Trying different secrets for each host in one tls entry
• Creating many Ingress resources unnecessarily
• Not using SAN certificates for multiple domains