Elastic Container Service (ECS) Overview
What is ECS?
- ECS: Managed service to run containers, typically using Docker.
- Docker: Tool to launch containers, ensuring isolation between container instances.
- ECS Functionality: Launch, set up, and monitor Docker containers on ECS clusters.
Infrastructure Options for Running Docker Containers
- Serverless Option (Fargate)
- Hands-off approach.
- Easier to use for beginners.
- Managed Option (EC2 Instances)
- Requires management of EC2 instances.
- Involves software upgrades, patches, and security management.
Scalability with ECS
- Auto Scaling: Handle variable volume based on metrics like traffic, memory, or CPU utilization.
- Use Cases: Useful for ad hoc jobs or full-scale services needing constant container availability.
Cost Efficiency
- Multiple Containers on Single Compute Resource: Host multiple Docker tasks on one instance.
- Reduced Overhead with Docker: Only one operating system needed for multiple containers.
Comparison to Other Options
- Lambda: Serverless; focus on code without infrastructure concerns.
- EC2: Needs code deployment and infrastructure management.
- ECS: Middle ground offering containerization advantages with less infrastructure management than EC2.
How ECS Works from a User Perspective
Setting Up ECS
- Docker File: Define settings, operating system, dependencies, source code, and startup scripts.
- Build Docker Image: Upload to Elastic Container Repository (ECR).
- ECR stores image histories for easy rollback.
Defining Tasks
- Task: Abstraction over containers; tells ECS how to spin up Docker containers.
- Can contain multiple containers (e.g., REST API and database separation).
- Specify resources, port mappings, etc.
Setting Up Clusters
- Cluster: Abstract resource farm with EC2 instances or Fargate.
- Launching Tasks: Specify tasks to run on a cluster.
Services and Scalability
- Service: Suitable for long-running applications, specifying a minimum number of tasks.
- Monitors containers for health and provides metrics and dashboard tools.
- Load Balancer: Distributes traffic across containers, ensuring resource availability.
Additional Resources
- Video walkthroughs available for console setup using Docker files.
For more detailed explanations, additional resources such as video links are provided in the original lecture content.