Amazon EC2 (Elastic Compute Cloud)
Amazon EC2 is a web service provided by Amazon Web Services (AWS) that offers resizable, virtual computing capacity in the cloud.
It allows users to rent virtual machines (instances) to run applications, scale computing resources up or down based on demand, and pay only for the capacity used.
EC2 instance
An EC2 instance is a virtual machine (VM) running on AWS’s physical servers, configured with a specific operating system, CPU, memory, storage, and networking capabilities based on user requirements.
Amazon EC2 Instance Types
- General purpose: General purpose instances provide a balanced mix of compute, memory, and networking resources. They are ideal for diverse workloads, like web services, code repositories, and when workload performance is uncertain.
- Compute optimized: Compute optimized instances are ideal for compute-intensive tasks, such as gaming servers, high performance computing (HPC), machine learning, and scientific modeling.
- Memory optimized: Memory optimized instances are used for memory-intensive tasks like processing large datasets, data analytics, and databases. They provide fast performance for memory-heavy workloads.
- Accelerated computing: Accelerated computing instances use hardware accelerators, like graphics processing units (GPUs), to efficiently handle tasks, such as floating-point calculations, graphics processing, and machine learning.
- Storage optimized: Storage optimized instances are designed for workloads that require high performance for locally stored data, such as large databases, data warehousing, and I/O-intensive applications.
Ways to interact with AWS services
- AWS Management Console: The AWS Management Console is a web interface for managing AWS services, offering quick access to services, search functionality, and simplified workflows.
- AWS CLI: With the AWS CLI, you manage multiple AWS services directly from the command line across Windows, macOS, and Linux.
- AWS SDK: The AWS SDK simplifies integrating AWS services into your applications by providing APIs for various programming languages.
Compute and shared responsibility
The AWS Shared Responsibility Model outlines the division of duties between the customer and AWS.
AWS handles the security of the cloud (hardware and infrastructure), whereas the customer is responsible for security in the cloud (applications, data, and access control).
AMI (Amazon Machine Images)
AMIs are pre-built virtual machine images that have the basic components for what is needed to start an instance.
AMIs provide repeatability through a consistent environment for every new instance.
AMI components
An AMI includes the operating system, storage setup, architecture type, permissions for launching, and any extra software that is already installed.
You can use one AMI to launch several EC2 instances that all have the same setup.
Three ways to use AMIs
- You can create your own by building a custom AMI with specific configurations and software tailored to your needs.
- You can use pre-configured AWS AMIs, which are set up for common operating systems and software.
- You can purchase AMIs from the AWS Marketplace, where third-party vendors offer specialized software designed for specific use cases.
Scalability
Scalability refers to the ability of a system to handle an increased load by adding resources.
- Scale up: add more power to existing machine
- Scale out: add more machines
Elasticity
Elasticity is the ability to automatically scale resources up or down in response to real-time demand.
A system can then rapidly adjust its resources, scaling out during periods of high demand and scaling in when the demand decreases.
Amazon EC2 Auto Scaling
Amazon EC2 Auto Scaling automatically adjusts the number of EC2 instances based on changes in application demand, providing better availability.
- Dynamic scaling adjusts in real time to fluctuations in demand.
- Predictive scaling preemptively schedules the right number of instances based on anticipated demand.
Auto Scaling groups
Auto Scaling groups are collections of EC2 instances that can scale in or out to meet your application’s needs.
Key settings:
- The minimum capacity defines the least number of EC2 instances required to keep the application running.
- The desired capacity is the ideal number of instances needed to handle the current workload, which Auto Scaling aims to maintain.
- The maximum capacity sets an upper limit on the number of instances that can be launched, preventing over-scaling and controlling costs.
Elastic Load Balancing
Elastic Load Balancing (ELB) automatically distributes incoming application traffic across multiple resources, such as EC2 instances, to optimize performance and reliability.
A load balancer serves as the single point of contact for all incoming web traffic to an Auto Scaling group.
As the number of EC2 instances fluctuates in response to traffic demands, incoming requests are first directed to the load balancer. From there, the traffic is distributed evenly across the available instances.
Although ELB and Amazon EC2 Auto Scaling are distinct services, they work in tandem to enhance application performance and ensure high availability.
ELB routing methods
- Round Robin: Distributes traffic evenly across all available servers in a cyclic manner.
- Least Connections: Routes traffic to the server with the fewest active connections, maintaining a balanced load.
- IP Hash: Uses the client’s IP address to consistently route traffic to the same server.
- Least Response Time: Directs traffic to the server with the fastest response time, minimizing latency.
Monolithic applications
In a traditional approach to application architecture, the components—such as database logic, web application servers, user interfaces, and business logic—are tightly coupled.
Microservices architecture
In this approach, application components are loosely coupled, meaning that if one component fails, the others continue to function normally.
The failure of a single component does not impact the entire system.
This design promotes greater flexibility and reliability in the application.
EventBridge
EventBridge is a serverless service that helps connect different parts of an application using events, helping to build scalable, event-driven systems.
Amazon SQS (Simple Queue Service)
Amazon SQS is a message queuing service that facilitates reliable communication between software components.
In Amazon SQS, an application places messages into a queue, and a user or service retrieves the message, processes it, and then removes it from the queue.
Amazon SNS
Amazon SNS is a publish-subscribe service that publishers use to send messages to subscribers through SNS topics.
Example of the different emails for each topic.
AWS pricing options
- On-Demand Instances: Pay only for the compute capacity you consume with no upfront payments or long-term commitments required.
- Reserved Instances: Get a savings of up to 75 percent by committing to a 1-year or 3-year term for predictable workloads using specific instance families and AWS Regions.
- Spot Instances: Bid on spare compute capacity at up to 90 percent off the On-Demand price, with the flexibility to be interrupted when AWS reclaims the instance.
- Savings Plans: Save up to 72 percent across a variety of instance types and services by committing to a consistent usage level for 1 or 3 years.
- Dedicated Hosts: Reserve an entire physical server for your exclusive use. This option offers full control and is ideal for workloads with strict security or licensing needs.
- Dedicated Instances: Pay for instances running on hardware dedicated solely to your account. This option provides isolation from other AWS customers.
