In a Monolithic Architecture, a single application is responsible for all aspects of the system. This includes:

Characteristics:

Tightly Coupled Functionality: All components of the application are interconnected and interdependent. Changes to one part of the system can affect others.

Microservices Architecture involves multiple applications or services, each responsible for a specific function or set of functions.

Characteristics:

Isolated Functionality: Each service operates independently and is stateless. This allows for isolated updates and scaling.

Isolation: VMs provide isolation through separate operating systems and virtualized hardware. This can lead to resource conflicts, security issues, and inefficient use of space.
Resource Overhead: Higher, as each VM includes its own OS in addition to the application.
Startup Time: Slower, as it requires booting a full operating system.
Management: Typically managed through hypervisors like VMware or Hyper-V.

Structure: Containers share the host OS kernel and include only the application and its dependencies.
Isolation: Achieved through process-level isolation using namespaces and control groups.
Resource Overhead: Lower, as containers are lightweight and share the host OS.
Startup Time: Faster (seconds), since containers leverage the already running host OS.
Management: Managed using services like AWS ECS (Elastic Container Service), EKS (Elastic Kubernetes Service), or other container orchestration tools.

Definition: Kubernetes is an open-source container orchestration system designed for automating deployment, scaling, and management of containerized applications.
Origin: Created by Google and now maintained by the Cloud Native Computing Foundation (CNCF).
Commonly Known As: "k8s," with "8" representing the number of letters between "k" and "s."
Advantage: Kubernetes can run containers distributed across multiple VMs.
Unique Component: Pods – a group of one or more containers sharing storage, network resources, and other settings.
Use Case: Ideal for managing large-scale microservices architectures with numerous services.

Definition: Docker is a platform-as-a-service (PaaS) that uses OS-level virtualization to deliver software in packages called containers.
History: Docker popularized open-source containerization. When people refer to containers, they often think of Docker.
Components:
- Docker CLI: Command-line interface for managing containers.
- Dockerfile: A configuration file that describes how to build a container.
- Docker Compose: A tool for defining and running multi-container Docker applications.
- Docker Swarm: An orchestration tool for managing multi-container deployments.
- Docker Hub: A public repository for container images.
OCI: The Open Container Initiative, established by Docker, creates industry standards for container formats and runtimes. It is now maintained by the Linux Foundation.
Trends: Docker has faced criticism for introducing a paid model for open-source software, leading to alternatives like Podman gaining popularity.

Podman: An OCI-compliant container engine that is a drop-in replacement for Docker. Unlike Docker, Podman does not use a daemon and supports creating pods similar to Kubernetes.
Buildah: A tool for building OCI container images.
Skopeo: A tool for moving container images between different types of container storage.

Elastic Container Service (ECS):
- No-Cloud Starts: Provides self-managed EC2 instances.
- AWS Fargate: A serverless compute engine for containers.
- Scale to Zero Cost: Can scale down to zero to save costs.
Elastic Kubernetes Service (EKS):
- Open Source: Uses Kubernetes for container orchestration.
- Avoids Vendor Lock-In: Supports standard Kubernetes features.
AWS Lambda:
- Focus: Only on code. Supports short-running tasks and custom container deployments.

Elastic Beanstalk (EB): Platform-as-a-Service (PaaS) that simplifies the deployment and management of applications.
App Runner: Platform-as-a-Service specifically designed for running containerized applications.
AWS Copilot CLI: Simplifies the building, releasing, and operating of containerized applications on AWS App Runner, ECS, and Fargate.

Elastic Container Registry (ECR): A managed repository for Docker images.
X-Ray: Analyzes and debugs distributed applications and microservices.
Step Functions: Orchestrates workflows by stitching together AWS Lambda functions and ECS tasks.

Day16: AWS Containers