Migrating from Docker Swarm to AWS EKS: What I Learned

Why We Moved Away from Swarm

Docker Swarm served us well, but we hit its ceiling: no native HPA, limited observability hooks, and no ecosystem for GitOps tooling.

Migration Phases

Phase 1 — Containerize & Validate

Every service already had a Dockerfile. We focused on:

Phase 2 — EKS Cluster Setup

eksctl create cluster \
  --name prod-cluster \
  --version 1.29 \
  --nodegroup-name standard \
  --node-type t3.medium \
  --nodes-min 2 --nodes-max 10 \
  --managed

Phase 3 — Helm Charts

We wrote Helm charts for each service, parameterized by environment. This made staging → prod promotion a one-liner.

Phase 4 — Observability

Wins