Introduction

When deploying applications in Kubernetes (K8s), managing and updating the configurations dynamically is crucial for maintaining application resilience and performance. One popular approach is using Envoy, a high-performance proxy, which can be configured dynamically via a Kubernetes ConfigMap. This article explores how to achieve dynamic configuration of Envoy using ConfigMaps, ensuring seamless updates and scalability in a K8s environment.

Understanding Envoy and ConfigMaps

What is Envoy?

Envoy is a high-performance open-source edge and service proxy designed for cloud-native applications. It operates at Layer 7 (Application Layer) and acts as a communication bus for microservices, providing capabilities such as load balancing, resilience features, and observability.

What are ConfigMaps?

ConfigMaps in Kubernetes are API resources used to store non-confidential configuration data in key-value pairs. They enable separation of configuration from application code, thereby allowing dynamic updates without needing to rebuild container images or redeploy pods.

Dynamic Configuration of Envoy

Envoy can be configured using a static configuration file, which is problematic in dynamic environments as any change requires a restart of the proxy. Instead, a dynamic configuration approach can be implemented using ConfigMaps, thus allowing live updates to Envoy without downtime.

Creating a ConfigMap in Kubernetes

A ConfigMap can be created using YAML configuration files. Here's a simple example of how to define a ConfigMap for Envoy:

• name: listener_0
  • filters:
    • name: envoy.filters.network.http_connection_manager
      • name: local_service
        • match:
      • name: envoy.filters.http.router
• name: service_cluster
  • lb_endpoints:
    • endpoint:
• name: envoy
  • name: envoy-config
• name: envoy-config
• Namespace and Names: Ensure ConfigMaps correspond to the correct namespaces and have unique names.
• Secrets Management: ConfigMaps don’t handle sensitive data. Use Kubernetes Secrets for configurations involving sensitive data.
• Rolling Updates: Use rolling updates to apply configuration changes progressively to minimize downtime.
• Conflict Resolution: Ensure changes to ConfigMaps don’t conflict with running configurations that could affect service availability.
  • name: local_service
    • match: