Skip to main content

​
Overview

ConfigMaps provide a way to inject configuration data into application containers. The exchange platform uses ConfigMaps to manage non-sensitive configuration for all services including database connections, Redis URLs, and service-specific settings.

​
ConfigMap Manifests

​
PostgreSQL Database Configuration

The exchange-postgres-config ConfigMap manages PostgreSQL database credentials and settings. Location: postgres-db/config-map.yml 
apiVersion: v1
kind: ConfigMap
metadata:
  name: exchange-postgres-config
data:
  POSTGRES_USER: root
  POSTGRES_PASSWORD: root
  POSTGRES_DB: exchange-db
Configuration Keys:
KeyValueDescription
POSTGRES_USERrootPostgreSQL database username
POSTGRES_PASSWORDrootPostgreSQL database password
POSTGRES_DBexchange-dbDatabase name
Used By: exchange-postgres-deployment Reference: postgres-db/deployment.yml:20-35

​
Engine Service Configuration

The exchange-engine-config ConfigMap provides database and Redis connection strings for the engine service. Location: engine/config-map.yml 
apiVersion: v1
kind: ConfigMap
metadata:
  name: exchange-engine-config
data:
  database_url: "postgres://root:[email protected]:80/exchange-db"
  redis_url: "redis://exchange-redis-service.default.svc.cluster.local:80"
Configuration Keys:
KeyValueDescription
database_urlPostgreSQL connection stringFull database URL with credentials and service endpoint
redis_urlRedis connection stringRedis service URL for pub/sub and caching
Used By: exchange-engine-deployment Reference: engine/deployment.yml:18-28

​
Database Processor Configuration

The exchange-db-processor-config ConfigMap manages configuration for the database processing service. Location: db-processor/config-map.yml 
apiVersion: v1
kind: ConfigMap
metadata:
  name: exchange-db-processor-config
data:
  database_url: "postgres://root:[email protected]:80/exchange-db"
  redis_url: "redis://exchange-redis-service.default.svc.cluster.local:80"
Configuration Keys:
KeyValueDescription
database_urlPostgreSQL connection stringDatabase connection for processing operations
redis_urlRedis connection stringRedis for job queues and event handling
Used By: exchange-db-processor-deployment Reference: db-processor/deployment.yml:18-28

​
WebSocket Service Configuration

The exchange-ws-stream-config ConfigMap configures the WebSocket streaming service. Location: websocket/config-map.yml 
apiVersion: v1
kind: ConfigMap
metadata:
  name: exchange-ws-stream-config
data:
  ws_stream_url: "0.0.0.0:4000"
  redis_url: "redis://exchange-redis-service.default.svc.cluster.local:80"
Configuration Keys:
KeyValueDescription
ws_stream_url0.0.0.0:4000WebSocket server bind address and port
redis_urlRedis connection stringRedis for real-time message streaming
Used By: exchange-ws-stream-deployment Reference: websocket/deployment.yml:20-30

​
Usage Patterns

​
Referencing ConfigMap Values in Deployments

ConfigMap values are injected into containers as environment variables using configMapKeyRef: 
env:
  - name: DATABASE_URL
    valueFrom:
      configMapKeyRef:
        name: exchange-engine-config
        key: database_url
  - name: REDIS_URL
    valueFrom:
      configMapKeyRef:
        name: exchange-engine-config
        key: redis_url

​
Applying ConfigMaps

Apply ConfigMaps before deploying dependent services: 
# Apply individual ConfigMap
kubectl apply -f postgres-db/config-map.yml

# Apply all ConfigMaps
kubectl apply -f postgres-db/config-map.yml \
               -f engine/config-map.yml \
               -f db-processor/config-map.yml \
               -f websocket/config-map.yml

​
Viewing ConfigMaps

# List all ConfigMaps
kubectl get configmaps

# View specific ConfigMap
kubectl describe configmap exchange-engine-config

# Get ConfigMap data in YAML format
kubectl get configmap exchange-engine-config -o yaml

​
Updating ConfigMaps

# Edit ConfigMap directly
kubectl edit configmap exchange-engine-config

# Or update from file
kubectl apply -f engine/config-map.yml

# Restart pods to pick up changes
kubectl rollout restart deployment exchange-engine-deployment

​
Best Practices

​
Security Considerations

Never store sensitive data like passwords, API keys, or tokens in ConfigMaps. Use Secrets instead. ConfigMaps are stored unencrypted in etcd.
Current Issue: The exchange-postgres-config ConfigMap stores the database password in plain text. For production environments, migrate these credentials to a Secret.

​
Service Discovery

All services use Kubernetes DNS for service discovery: 
<service-name>.<namespace>.svc.cluster.local:<port>
Example: exchange-postgres-service.default.svc.cluster.local:80

​
Configuration Organization

  • One ConfigMap per service: Each service has its own ConfigMap for isolation
  • Co-located with deployments: ConfigMaps are stored in the same directory as their corresponding deployment files
  • Clear naming convention: All ConfigMaps follow the pattern exchange-<service>-config

​
Immutability

For production environments, consider making ConfigMaps immutable: 
apiVersion: v1
kind: ConfigMap
metadata:
  name: exchange-engine-config
immutable: true
data:
  database_url: "..."
  redis_url: "..."
Benefits:
  • Protects against accidental updates
  • Improves cluster performance by reducing load on kube-apiserver
  • Forces explicit versioning through new ConfigMap creation

​
Version Control

Always version control your ConfigMap manifests and track changes through Git commits. This provides an audit trail and enables easy rollbacks.

​
Connection String Patterns

​
PostgreSQL URLs

Format: postgres://[user]:[password]@[host]:[port]/[database] Example: 
postgres://root:[email protected]:80/exchange-db

​
Redis URLs

Format: redis://[host]:[port] Example: 
redis://exchange-redis-service.default.svc.cluster.local:80

​
Troubleshooting

​
ConfigMap Not Found

# Check if ConfigMap exists
kubectl get configmap exchange-engine-config

# If not found, apply it
kubectl apply -f engine/config-map.yml

​
Pod Not Picking Up ConfigMap Changes

ConfigMap updates don’t automatically restart pods: 
# Manually restart the deployment
kubectl rollout restart deployment exchange-engine-deployment

# Or delete pods to force recreation
kubectl delete pod -l app=exchange-engine

​
Verify Environment Variables

Check that ConfigMap values are properly injected: 
# Get pod name
kubectl get pods -l app=exchange-engine

# Check environment variables
kubectl exec <pod-name> -- env | grep -E '(DATABASE_URL|REDIS_URL)'

Build docs developers (and LLMs) love

Get started for freeTalk to us