EKS Troubleshooting#

EKS failure modes combine Kubernetes problems with AWS-specific issues. Most fall into a handful of categories: IAM permissions, networking/security groups, missing tags, and add-on misconfiguration.

Nodes Not Joining the Cluster#

Symptoms: kubectl get nodes shows fewer nodes than expected. ASG shows instances running, but they never register.

aws-auth ConfigMap Missing Node Role#

The most common cause. Worker nodes authenticate via aws-auth. If the node IAM role is not mapped, nodes are rejected silently.

Ephemeral Cloud Clusters#

Ephemeral clusters exist for one purpose: validate something, then disappear. They are not staging environments, not shared dev clusters, not long-lived resources that someone forgets to turn off. The operational model is strict – create, validate, destroy – and the entire sequence must be automated so that destruction cannot be forgotten.

The cost of getting this wrong is real. A three-node EKS cluster left running over a weekend costs roughly $15. Left running for a month, $200. Multiply by the number of developers or CI pipelines that create clusters, and forgotten ephemeral infrastructure becomes a significant budget line item. Every template in this article includes auto-destroy mechanisms to prevent this.

What Capacity Planning Solves#

Running out of capacity during a traffic spike causes outages. Over-provisioning wastes money continuously. Capacity planning is the process of measuring what you use now, projecting what you will need, and ensuring resources are available before demand arrives. Without it, you are either constantly firefighting resource exhaustion or explaining to finance why your cloud bill doubled.

Capacity planning is not a one-time exercise. It is a recurring process – monthly for fast-growing services, quarterly for stable ones.

Infrastructure Knowledge Scoping for Agents#

An agent working on infrastructure tasks needs to operate at the right level of specificity. Giving generic Kubernetes advice when the user runs EKS with IRSA is unhelpful – the agent misses the IAM integration that will make or break the deployment. Giving EKS-specific advice when the user runs minikube on a laptop is equally unhelpful – the agent references services and configurations that do not exist.

Multi-Cloud Networking Patterns#

Multi-cloud networking connects workloads across two or more cloud providers into a coherent network. The motivations vary – vendor redundancy, best-of-breed service selection, regulatory requirements – but the challenges are the same: private connectivity between isolated networks, consistent service discovery, and traffic routing that handles failures.

VPN Tunnels Between Clouds#

IPsec VPN tunnels are the simplest way to connect two cloud networks. Each provider offers managed VPN gateways that terminate IPsec tunnels, encrypting traffic between VPCs without exposing it to the public internet.

Terraform Cloud Architecture Patterns#

The three-tier architecture — networking, managed Kubernetes, managed database — is the most common pattern for production deployments on any major cloud. The concepts are identical across AWS, Azure, and GCP. The Terraform code is not. Resource names differ, required arguments differ, default behaviors differ, and the gotchas that catch agents and humans are cloud-specific.

This article shows the real Terraform for each layer on each cloud, side by side, so agents can write correct infrastructure code for whichever cloud the user deploys to.

Zero-Egress Architecture with Cloudflare R2#

Every major cloud provider charges you to download your own data. AWS S3 charges $0.09/GB. Google Cloud Storage charges $0.12/GB. Azure Blob charges $0.087/GB. These egress fees are the most unpredictable line item on cloud bills – they scale with success. The more users download your data, the more you pay.

Cloudflare R2 charges $0 for egress. Zero. Unlimited. Every download is free, whether it is 1 GB or 100 TB. R2 uses the S3-compatible API, so existing tools and SDKs work without changes. This single pricing difference changes how you architect storage, serving, and cross-cloud data flow.

VPC Concepts#

A Virtual Private Cloud is an isolated virtual network inside a cloud provider. Every resource you launch – EC2 instances, RDS databases, Lambda functions with VPC access – lives inside a VPC. The VPC defines an IP address range using CIDR notation, and all resources within it get addresses from that range.

The most common mistake is giving every VPC a /16 (65,536 addresses). This wastes IP space and causes problems later when you need to peer VPCs – overlapping CIDR blocks cannot be peered. Plan your IP allocation before building anything.

GitHub Actions Advanced Patterns#

Once you move past single-file workflows that run npm test on every push, GitHub Actions becomes a platform for building serious CI/CD infrastructure. The features covered here – reusable workflows, composite actions, matrix strategies, OIDC authentication, and caching – are what separate a working pipeline from a production-grade one.

Reusable Workflows#

A reusable workflow is a complete workflow file that other workflows can call like a function. Define it with the workflow_call trigger:

L4 vs L7 Load Balancing#

The distinction between Layer 4 and Layer 7 load balancing determines what the load balancer can see and what routing decisions it can make.

Layer 4 (Transport) load balancers work at the TCP/UDP level. They see source/destination IPs and ports but not the content of the traffic. They forward raw TCP connections to backends. This makes them fast (no protocol parsing), protocol-agnostic (works for HTTP, gRPC, database connections, custom protocols), and transparent (the backend sees the original packets, mostly). Use L4 for database connections, raw TCP services, and when you need maximum throughput with minimum latency.