ConfigMaps and Secrets in Microservices - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a ConfigMap in Kubernetes.

Microservices

kubectl create configmap [1] --from-literal=app_mode=production

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

Amy-config

Bsecret-config

Capp-secret

Dconfig-secret

Attempts:

3 left

💡 Hint

Common Mistakes

Using a name that suggests a Secret instead of a ConfigMap.

Confusing ConfigMap creation with Secret creation commands.

The command kubectl create configmap my-config --from-literal=app_mode=production creates a ConfigMap named my-config with a key app_mode set to production.

2fill in blank

medium

Complete the code to create a Secret with a password in Kubernetes.

Microservices

kubectl create secret generic [1] --from-literal=password=Pa$$w0rd

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

Aapp-config

Bconfigmap

Cdb-secret

Dapp-configmap

Attempts:

3 left

💡 Hint

Common Mistakes

Using ConfigMap names when creating Secrets.

Not using the correct command for Secrets.

The command kubectl create secret generic db-secret --from-literal=password=Pa$$w0rd creates a Secret named db-secret containing the password.

3fill in blank

hard

Fix the error in the command to mount a Secret as a volume in a Pod spec.

Microservices

volumes:
  - name: secret-volume
    secret:
      secretName: [1]

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

Amy-config

Bapp-configmap

Cconfigmap-secret

Ddb-secret

Attempts:

3 left

💡 Hint

Common Mistakes

Using ConfigMap names in the secretName field.

Misspelling the Secret name.

The secretName must match the name of an existing Secret. Here, db-secret is the correct Secret name to mount.

4fill in blank

hard

Fill both blanks to define environment variables from a ConfigMap and a Secret in a Pod spec.

Microservices

env:
  - name: APP_MODE
    valueFrom:
      configMapKeyRef:
        name: [1]
        key: app_mode
  - name: DB_PASSWORD
    valueFrom:
      secretKeyRef:
        name: [2]
        key: password

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

Amy-config

Bapp-config

Cdb-secret

Dapp-secret

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up ConfigMap and Secret names.

Using incorrect keys for the environment variables.

The environment variable APP_MODE comes from the ConfigMap named my-config, and DB_PASSWORD comes from the Secret named db-secret.

5fill in blank

hard

Fill all three blanks to create a Pod spec snippet that mounts a ConfigMap and a Secret as volumes and uses environment variables from both.

Microservices

volumes:
  - name: config-volume
    configMap:
      name: [1]
  - name: secret-volume
    secret:
      secretName: [2]
containers:
  - name: app-container
    image: myapp:latest
    volumeMounts:
      - name: config-volume
        mountPath: /etc/config
      - name: secret-volume
        mountPath: /etc/secret
    env:
      - name: APP_MODE
        valueFrom:
          configMapKeyRef:
            name: [3]
            key: app_mode

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

Amy-config

Bdb-secret

Capp-config

Dapp-secret

Attempts:

3 left

💡 Hint

Common Mistakes

Using Secret names where ConfigMap names are needed.

Mismatching volume names and mount paths.

The ConfigMap my-config is mounted as config-volume and used for the APP_MODE environment variable. The Secret db-secret is mounted as secret-volume.

Practice

1. What is the primary purpose of a ConfigMap in a microservices environment?

easy

A. To store encrypted passwords and tokens securely

B. To store non-sensitive configuration data separately from application code

C. To manage network traffic between microservices

D. To monitor the health of microservices

Solution

1. Step 1: Understand ConfigMap role

   A ConfigMap is designed to hold configuration data that is not sensitive, such as environment variables or config files, separate from the application code.

2. Step 2: Differentiate from Secrets

   Secrets are used for sensitive data like passwords, not ConfigMaps.

3. Final Answer:

   To store non-sensitive configuration data separately from application code -> Option B

4. Quick Check:

   ConfigMap = Non-sensitive config [OK]

Hint: ConfigMaps hold safe config, Secrets hold sensitive info [OK]

Common Mistakes:

• Confusing ConfigMaps with Secrets
• Thinking ConfigMaps encrypt data
• Assuming ConfigMaps manage network or health

2. Which of the following is the correct way to create a Secret in Kubernetes using a literal value?

easy

A. kubectl create secret generic mysecret --from-literal=password=12345

B. kubectl create configmap mysecret --from-literal=password=12345

C. kubectl secret create mysecret --from-file=password.txt

D. kubectl create secret mysecret --password=12345

Solution

1. Step 1: Recall Kubernetes Secret creation syntax

   The correct command uses kubectl create secret generic with --from-literal to create a secret from a literal key-value pair.

2. Step 2: Eliminate incorrect options

   kubectl create configmap mysecret --from-literal=password=12345 uses configmap instead of secret, kubectl secret create mysecret --from-file=password.txt uses wrong command syntax, kubectl create secret mysecret --password=12345 uses invalid flag.

3. Final Answer:

   kubectl create secret generic mysecret --from-literal=password=12345 -> Option A

4. Quick Check:

   Secret creation uses 'kubectl create secret generic' [OK]

Hint: Secret creation uses 'kubectl create secret generic' [OK]

Common Mistakes:

• Using configmap command instead of secret
• Wrong flags like --password
• Confusing file and literal input

3. Given this Kubernetes pod spec snippet, what will be the value of environment variable API_KEY inside the container?

env:
  - name: API_KEY
    valueFrom:
      secretKeyRef:
        name: mysecret
        key: api_key

medium

A. An empty string because 'api_key' is not defined

B. The literal string 'api_key'

C. The value stored under key 'api_key' in the Secret named 'mysecret'

D. The value of a ConfigMap named 'mysecret'

Solution

1. Step 1: Understand env var from secretKeyRef

   The environment variable API_KEY is set from a Secret named mysecret, specifically the key api_key.

2. Step 2: Clarify what value is assigned

   The value assigned is the secret data stored under that key, not the literal string or empty.

3. Final Answer:

   The value stored under key 'api_key' in the Secret named 'mysecret' -> Option C

4. Quick Check:

   secretKeyRef pulls secret value by key [OK]

Hint: secretKeyRef uses secret's key value, not literal text [OK]

Common Mistakes:

• Assuming it uses the key name as string
• Confusing ConfigMap with Secret
• Thinking it defaults to empty if key missing

4. A developer tries to mount a Secret as a volume in a pod but gets an error. Which of these is the most likely cause?

medium

A. The Secret does not exist or has a different name than specified

B. The ConfigMap is missing required keys

C. The pod spec uses configMapKeyRef instead of secretKeyRef

D. The volume mount path is outside the container filesystem

Solution

1. Step 1: Identify common Secret mount errors

   Mounting a Secret as a volume requires the Secret to exist with the exact name referenced.

2. Step 2: Evaluate other options

   ConfigMap keys missing affect ConfigMaps, not Secrets. Using configMapKeyRef instead of secretKeyRef is for env vars, not volumes. Volume mount path errors cause different errors.

3. Final Answer:

   The Secret does not exist or has a different name than specified -> Option A

4. Quick Check:

   Secret volume mount fails if Secret missing [OK]

Hint: Check Secret name exists before mounting volume [OK]

Common Mistakes:

• Mixing ConfigMap and Secret references
• Ignoring Secret existence before mount
• Confusing env var refs with volume mounts

5. You want to securely provide database credentials to multiple microservices without exposing them in code or logs. Which approach best uses ConfigMaps and Secrets together?

hard

A. Embed credentials directly in microservice code and use ConfigMaps for feature flags

B. Store credentials in ConfigMaps and encrypt them manually; use Secrets for logging configs

C. Put all configs and secrets in ConfigMaps for simplicity; avoid Secrets

D. Store all credentials in a Secret and non-sensitive configs in ConfigMaps; mount both as environment variables

Solution

1. Step 1: Separate sensitive and non-sensitive data

   Best practice is to keep sensitive data like credentials in Secrets and non-sensitive configs in ConfigMaps.

2. Step 2: Use environment variables for flexibility

   Mounting both as environment variables allows microservices to access configs securely without code changes.

3. Final Answer:

   Store all credentials in a Secret and non-sensitive configs in ConfigMaps; mount both as environment variables -> Option D

4. Quick Check:

   Secrets for sensitive, ConfigMaps for safe config [OK]

Hint: Secrets for sensitive data, ConfigMaps for safe config [OK]

Common Mistakes:

• Putting secrets in ConfigMaps unencrypted
• Embedding credentials in code
• Using Secrets for non-sensitive data