Serverless Container Operations with AWS Fargate - Usage Patterns for ECS and EKS
Run serverless containers without managing instances. Learn how to choose between ECS and EKS, and optimize costs through task sizing.
How Fargate Works and How It Differs from EC2 Launch Type
Fargate is a serverless compute engine for ECS and EKS. With the EC2 launch type, you manage the provisioning, scaling, and patching of EC2 instances that run your containers, but Fargate completely abstracts all of this away. You simply specify vCPU (0.25 to 16) and memory (0.5 GiB to 120 GiB) in your task definition, and AWS automatically provisions the container execution environment. Each task runs in an isolated microVM, eliminating kernel sharing between tasks and strengthening security isolation.
Choosing Between ECS on Fargate and EKS on Fargate
ECS on Fargate is an AWS-native container orchestration that can be operated simply with three concepts: task definitions, services, and clusters. It provides ALB integration, service mesh via Service Connect, and service discovery via CloudMap out of the box. EKS on Fargate runs Kubernetes Pods on Fargate. Choose this when you want to leverage the Kubernetes ecosystem (Helm, Argo CD, Prometheus, etc.) or when standardizing on Kubernetes across multiple clouds. However, EKS on Fargate has limitations: DaemonSets cannot be used, and startup is slower than EC2 nodes because an ENI is assigned per Pod.
Cost Optimization
Fargate pricing is pay-per-use based on vCPU-seconds and memory GB-seconds. Proper task sizing is the key to cost optimization. Use CloudWatch Container Insights to measure actual CPU and memory utilization, then reduce resources for over-provisioned tasks. Fargate Spot offers up to 70% discount compared to on-demand, with a 30-second grace period after a SIGTERM signal is sent upon interruption. It's well-suited for interrupt-tolerant workloads like queue-based workers and batch processing. Compute Savings Plans apply across Fargate, Lambda, and EC2, offering up to 50% discount with a 1-year commitment. For a systematic understanding of Fargate, check out related books (Amazon).
Summary
Fargate is a serverless compute engine that eliminates infrastructure management from container operations. Start simply with ECS on Fargate, and migrate to EKS on Fargate when Kubernetes is needed. Optimize costs with Fargate Spot and Savings Plans, and continuously monitor resource utilization with Container Insights.