Kubernetes Cluster Configuration

This guide provides an overview of our Kubernetes cluster architecture and configuration management approach using GitOps with ArgoCD.

Architecture Overview

Our infrastructure follows a strict GitOps approach with the following principles:

• Base configurations containing common settings and defaults
• Environment-specific overlays for customized deployments
• Progressive deployment through ArgoCD sync waves
• Resource graduation across environments when applicable

Network Architecture

Our modern networking stack is built on:

• Cilium (v1.17+)

  • CNI for network connectivity
  • Service mesh capabilities
  • Network policies
  • Cluster mesh (future capability)

• Gateway API

  • Modern ingress management
  • Replaces traditional Ingress resources
  • Enhanced traffic routing capabilities

Gateway Classes and Structure

Gateway Classes:
  external:            # Internet-facing services
    - HTTP/HTTPS routes
    - Load balancing
    - External DNS integration
  internal:           # Cluster-local services
    - Internal DNS resolution
    - Service mesh integration
    - Cross-namespace communication
  tls-passthrough:    # Direct TLS termination
    - Secure services
    - Certificate management via cert-manager

Node Management

Safe Node Drainage and Reboot

To safely reboot a node, follow these steps:

1. Cordon the node to prevent new workloads:

kubectl cordon node-name

2. Drain workloads (ignore DaemonSets, handle ephemeral storage):

kubectl drain node-name --ignore-daemonsets --delete-emptydir-data

3. Reboot using talosctl (replace IP with your node's IP):

talosctl reboot --nodes 10.25.150.21

4. Uncordon the node after it's back online:

kubectl uncordon node-name

Node Maintenance Best Practices

• Always drain nodes before maintenance
• Verify pod rescheduling before proceeding
• Monitor node health after maintenance
• Ensure cluster has capacity for workload redistribution
• Consider impact on stateful applications