ConfigMaps and Secrets in Microservices - Architecture Diagram

System Overview - ConfigMaps and Secrets

This system manages configuration data and sensitive information for microservices. It ensures that services can access configuration settings and secrets securely and efficiently without hardcoding them into the application code.

Key requirements include secure storage of secrets, easy updates of configuration without redeploying services, and controlled access to sensitive data.

Architecture Diagram

User
  |
  v
Load Balancer
  |
  v
API Gateway
  |
  v
+----------------+       +----------------+
| Config Service  |<----->| Secret Service  |
+----------------+       +----------------+
       |                          |
       v                          v
+----------------+          +----------------+
| ConfigMap Store|          | Secret Store   |
+----------------+          +----------------+
       |                          |
       v                          v
+---------------------------------------------+
|               Microservices                  |
+---------------------------------------------+

Components

User

user

Initiates requests to microservices

Load Balancer

load_balancer

Distributes incoming requests evenly to API Gateway instances

API Gateway

api_gateway

Routes requests to appropriate microservices and handles authentication

Config Service

service

Provides configuration data from ConfigMaps to microservices

Secret Service

service

Provides sensitive data securely from Secrets to microservices

ConfigMap Store

config_store

Stores non-sensitive configuration data accessible by Config Service

Secret Store

secret_store

Stores encrypted sensitive data accessible by Secret Service

Microservices

service

Consume configuration and secrets to perform business logic

Request Flow - 13 Hops

User → Load Balancer

Load Balancer → API Gateway

API Gateway → Microservices

Microservices → Config Service

Config Service → ConfigMap Store

ConfigMap Store → Config Service

Microservices → Secret Service

Secret Service → Secret Store

Secret Store → Secret Service

Secret Service → Microservices

Microservices → API Gateway

API Gateway → Load Balancer

Load Balancer → User

Failure Scenario

Component Fails:Secret Store

Impact:Microservices cannot retrieve sensitive data, causing failures in operations requiring secrets. Configuration data remains accessible.

Mitigation:Use replicated secret stores with failover. Cache decrypted secrets temporarily in Secret Service to serve reads during outage.

Architecture Quiz - 3 Questions

Which component securely stores sensitive data like passwords?

A ConfigMap Store

B Secret Store

C Config Service

D API Gateway

Design Principle

This architecture separates configuration data and secrets into dedicated services and stores. It ensures secure handling of sensitive information while allowing easy updates to configuration without redeploying microservices. The use of API Gateway and Load Balancer provides scalable and secure request routing.

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