- ECS provides a way to run Docker containers on a cluster of Amazon EC2 instances. It consists of container instances, tasks, services, and a scheduler. - A task definition specifies the details of a task/container such as name, image, memory requirements, and port mappings. - A service keeps desired number of tasks running and provides load balancing using an ELB. It ensures tasks are rescheduled if they fail health checks. - The launch process involves setting up security, IAM roles, container instances, task definitions, services, and pushing Docker images to ECR.

1. ECS Quick Intro
@vinothiniraju

2. For the next 30 mins..
• ECR
• Intro & Components
• Architecture at high level
• Launch Process
• Scheduling a service
• Service Load Balancing
• Multi-task Deployment Demo
No covered:
• Autoscaling
• CI/CD
• Advanced scheduling
• Advanced task definitions

3. Intro & Components
• Intro
• Docker containers on a cluster of Amazon EC2 instances
• Components
• CLUSTER : Logical grouping of container instances, tasks are placed here
• CONTAINER INSTANCE : EC2 instance, requires ECS agent & registered with a cluster
• TASK DEFINITION : Application blueprints/compositions with 1 or more container definitions
• SCHEDULER : Method to place tasks on container instances.
• SERVICE : 1 or more running instances of applications
• TASK : single container task instance
• CONTAINER : Linux container

4. Task Definition
• Family (version controlled name)
• Container Definitions
• basic
• name *
• image *
• memory *
• portMappings [hostPort, containerPort, protocol tcp/udp]
• advanced
• Volumes

5. Service
• Autohealing (if unhealthy
it gets started again)
• Service Load Balancing
(ELB)
• Service Definition
Parameters
• # of tasks ie., containers
launched

6. Scheduling a service
• RunTask (ideal for batch jobs, evenly distributes the
tasks)
• StartTask
• All of the containers that are launched in a single
task definition are always placed on the same
container instance

7. Architecture at high level
Container Container
Docker
Container Instance
ECS Agent
Container Container
Docker
Container Instance
ECS Agent
Container Container
Docker
Container Instance
ECS Agent
AZ1 AZ2
ELB ELB
Amazon
ECS
Agent Communication Service API
Cluster Management Engine
Key Value Store
User Scheduler

8. Launch Process
STEP 1 : Security Group
STEP 2 : IAM User + Permissions : Amazon ECS First Run Wizard
[permissions]
STEP 3: Launch your container instances in a VPC
STEP 4: Create container cluster / ECR
STEP 5: Create task definition
STEP 6: Create service instance
STEP 7: Configure repository and Build, tag, and push Docker image

9. Service Load Balancing

10. Service LB configs
• It is not possible to map the load balancer port 80 to port 3030 on one container
instance and port 4040 on another container instance.
• You may choose to put two different containers behind the same load balancer
by defining multiple host ports in the service definition and adding those listener
ports to the load
• There is a limit of one load balancer per service.
• Your load balancer subnet configuration must include all subnets that your
container instances reside in.
• If a service's task fails the load balancer health check criteria, the task is killed
and restarted. This process continues until your service reaches the number of
desired running tasks.
Ref: http://docs.aws.amazon.com/AmazonECS/latest/developerguide/service-load-balancing.html

11. Demo
wordpress:
image: registry.hub.docker.com/wordpress:latest
links:
- wordpress_db:mysql
ports:
- 8080:80
wordpress_db:
image: registry.hub.docker.com/mariadb:latest
environment:
MYSQL_ROOT_PASSWORD: examplepass
phpmyadmin:
image: registry.hub.docker.com/corbinu/docker-phpmyadmin:latest
links:
- wordpress_db:mysql
ports:
- 8181:80
environment:
MYSQL_USERNAME: root
MYSQL_ROOT_PASSWORD: examplepass
Docker Compose Configuration

12. K8s vs AWS
(insights from nanit.com)
ECS K8s
Service
ELB+Service
+TaskDefinition
Replication Controller
Deployment
(30
concurrent
reqs)
More dropped update
requests while scaling
(9-14 requests dropped)
Less dropped update requests
while scaling (1M Request per
sec) - (0-2 requests dropped)
Volumes Attached to a host (EBS) Can attach to a container
Service
Discovery
No auto-discovery. Can
be done with the help of
ELB
Name & Group the services
Health
Check
Limited to HTTP/TCP
Flexibility through Exec command
(inside containers)
Cloud
Agnostic
No Portable
https://railsadventures.wordpress.com/2015/12/06/why-we-chose-kubernetes-over-ecs/

13. Thanks !