AWS | Use Cases : Lambda - Lambda(Container) - Containers(Farget/EC2) - EC2

 1. Use case for choosing Lambda over container-based deployment

Choose AWS Lambda instead of containers when you want event-driven, serverless execution without managing infrastructure.

Typical use cases

1. Event-driven processing

• Triggered by events from:

• Amazon S3 uploads
• Amazon DynamoDB streams
• Amazon EventBridge

        Example: Resize images when uploaded to S3.

2. Short-lived microservices

• APIs running behind Amazon API Gateway
• Small functions like validation, authentication, etc.

3. Sporadic workloads

• Jobs that run occasionally
• No need to pay for idle infrastructure.

4. Automatic scaling

• Traffic spikes → Lambda scales automatically.

Why Lambda here

• No server management
• Pay per execution
• Built-in scaling

---

2. Use case for choosing containers over Lambda

Choose containers (like Amazon ECS, Amazon EKS, or Docker deployments) when workloads require more control and longer execution time.

Typical use cases

1. Long-running services

• Backend APIs
• Web applications
• Streaming services

Lambda has execution limits, while containers can run indefinitely.

---

2. Custom runtime or dependencies

        If you need:

• special OS libraries
• GPU support
• custom runtime environments

Containers allow full environment control.

---

3. Stateful or complex applications

Examples:

• Machine learning inference services
• Video processing pipelines
• background workers

---

4. Consistent dev → prod environment
Docker containers ensure the same environment everywhere.

---

3. Use case for choosing EC2 over containers or Lambda

Choose Amazon EC2 when you need full control of the infrastructure.

Typical use cases

1. Legacy applications

Applications that:

• cannot be containerized
• require specific OS setups.

---

2. Custom networking or OS configuration

You need:

• kernel modifications
• custom drivers
• advanced networking.

---

3. Specialized hardware
Examples:

• GPU workloads
• FPGA workloads
• HPC computing.

---

4. Stateful workloads
Examples:

• large databases
• heavy caching systems

---

4. Use case for choosing Fargate over ECS EC2

Choose AWS Fargate instead of Amazon ECS with EC2 when you want containers without managing servers.

When Fargate is better

1. No infrastructure management

You don’t need to:

• patch servers
• scale EC2
• manage clusters.

---

2. Simple microservices

Perfect for:

• containerized APIs
• background jobs
• microservices architecture.

---

3. Variable workloads

Fargate automatically scales tasks.

---

When ECS EC2 is better

Use ECS EC2 when:

• you want lower cost at scale
• you need GPU or specialized hardware
• you want custom instance types

---

5. Use case for deploying Lambda using containers

AWS Lambda supports container images (up to 10GB).

Zip based lambda supports max 250 MB.

Use container-based Lambda when

1. Large dependencies

If your Lambda package exceeds normal limits.

Example:

• ML models
• heavy Python libraries.

---

2. Custom runtime
You want:

• custom Linux packages
• special frameworks.

---

3. Standardized CI/CD
If your organization already uses:

• Docker
• container pipelines.

---

4. Portability
You can reuse the same container for:

• Lambda
• ECS
• Kubernetes.

---

Simple Decision Summary

Scenario	Best Option
Event-driven small tasks	Lambda
Long-running microservices	Containers
Full infrastructure control	EC2
Containers without server management	Fargate
Large Lambda dependencies	Lambda container image

---

Simple rule many architects use:

• Lambda → event-driven
• Fargate → container microservices
• EC2 → full control workloads