AWS助理架构师认证培训 | EC2 Fundamentals

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EC2 Basics

Amazon EC2

• EC2 is one of the most popular of AWS' offering
• EC2 = Elastic Compute Cloud = Infrastructure as a Service
• It mainly consists in the capability of:Renting virtual machines (EC2)Storing data on virtual drives (EBS)Distributing load across machines (ELB)Scaling the services using an auto-scaling group (ASG)
• Knowing EC2 is fundamental to understand how the Cloud works

EC2 sizing & configuration options

• Operating System (OS): Linux, Windows or Mac OS
• How much compute power & cores (CPU)
• How much random-access memory (RAM)
• How much storage space:Network-attached (EBS & EFS)hardware (EC2 Instance Store)
• Network card: speed of the card, Public IP address
• Firewall rules: security group
• Bootstrap script (configure at first launch): EC2 User Data

EC2 User Data

• lt is possible to bootstrap our instances using an EC2 User data script
• bootstrapping means launching commands when a machine starts
• That script is only run once at the instance first start
• EC2 user data is used to automate boot tasks such as:Installing updatesInstalling softwareDownloading common files from the internetAnything you can think of
• The EC2 User Data Script runs with the root user

EC2 instance types: example

t2.micro is part of the AWS free tier (up to 750 hours per month)

Create an EC2 Instance with EC2 User Data to have a Website Hands on

Hands-On: Launching an EC2 Instance running Linux

• We'll be launching our first virtual server using the AWS Console
• We'll get a first high-level approach to the various parameters
• We'll see that our web server is launched using EC2 user data

EC2 Instance Types Basics

EC2 Instance Types - Overview

• You can use different types of EC2 instances that are optimised for different use cases (https://aws.amazon.com/ec2/instance-types/)

• AWS has the following naming convention:

m5.2xlarge

• m: instance class
• 5: generation (AWS improves them over time)
• 2xlarge: size within the instance class

EC2 Instance Types - General Purpose

• Great for a diversity of workloads such as web servers or code repositories
• Balance between:ComputeMemoryNetworking
• In the course, we will be using the t2.micro which is a General Purpose EC2 instance

EC2 Instance Types - Compute Optimized

• Great for compute-intensive tasks that require high performance processors:Batch processing workloadsMedia transcodingHigh performance web serversHigh performance computing (HPC)Scientific modeling &machine learningDedicated gaming servers

EC2 Instance Types - Memory Optimized

• Fast performance for workloads that process large data sets in memory
• Use cases:High performance, relational/non-relational databases Distributed web scale cache stores In-memory databases optimized for BI (business intelligence)Applications performing real-time processing of big unstructured data

EC2 Instance Types - Storage Optimized

• Great for storage-intensive tasks that require high, sequential read and write access to large data sets on local storage
• Use cases:High frequency online transaction processing (OLTP) systemsRelational & NoSQL databasesCache for in-memory databases (for example, Redis)Data warehousing applicationsDistributed file systems

EC2 Instance Type: example

Security Groups & Classic Ports Overview

Introduction to Security Groups

• Security Groups are the fundamental of network security in AWS
• They control how traffic is allowed into or out of our EC2 Instances

• Security groups only contain allow rules
• Security groups rules can reference by IP or by security group

Security Groups Deeper Dive

• Security groups are acting as a "firewall" on EC2 instances
• They regulate:Access to PortsAuthorised IP ranges - IPv4 and IPv6Control of inbound network (from other to the instance)Control of outbound network (from the instance to other)

Security Groups Diagram

Security Groups Good to know

• Can be attached to multiple instances
• Locked down to a region/VPC combination
• Does live "outside" the EC2 - if traffic is blocked the EC2 instance won't see it
• It's good to maintain one separate security group for SSH access
• If your application is not accessible (timeout), then it's a security group issue
• lf your application gives a "connection refused" error, then it's an application error or it's not launched
• All inbound traffic is blocked by default
• All outbound traffic is authorised by default

Referencing other security groups Diaram

Classic Ports to know

• 22 = SSH (Secure Shell) - log into a Linux instance
• 21 = FTP (File Transfer Protocol) - upload files into a file share
• 22 = SFTP (Secure File Transfer Protocol) - upload files using SSH
• 80 = HTTP - access unsecured websites
• 443 = HTTPS - access secured websites
• 3389 = RDP (Remote Desktop Protocol) - log into a Windows instance

SSH Overview

SSH Summary Table

Which Lectures to watch

• Mac / Linux:SSH on Mac / Linux lecture
• Windows:Putty LectureIf Windows 10: SSH on Windows 10 lecture
• All:EC2 Instance Connect lecture

SSH troubleshooting

• Students have the most problems with SSH
• lf things don't work...Re-watch the lecture. You may have missed something Read the troubleshooting guide Try EC2 Instance Connect
• If one method works (SSH, Putty or EC2 Instance Connect) you're good
• If no method works, that's okay, the course won't use SSH much

How to SSH using Linux or MAC

How to SSH into your EC2 Instance Linux / Mac OS X

• We'll learn how to SSH into your EC2 instance using Linux / Mac
• SSH is one of the most important function. It allows you to control a remote machine, all using the command line.

How to SSH using Windows

How to SSH into your EC2 Instance Windows

• We'll learn how to SSH into your EC2 instance using Windows
• SSH is one of the most important function. It allows you to control a remote machine, all using the command line

• We will configure all the required parameters necessary for doing SSH on Windows using the free tool Putty

EC2 Instance Purchasing Options

EC2 Instances Purchasing Options

• On-Demand Instances - short workload, predictable pricing, pay by second
• Reserved (1 & 3 years)Reserved Instances - long workloadsConvertible Reserved Instances - long workloads with flexible instances
• Savings Plans (1 & 3 years) - commitment to an amount of usage, long workload
• Spot Instances - short workloads, cheap, can lose instances (less reliable)
• Dedicated Hosts - book an entire physical server, control instance placement
• Dedicated Instances - no other customers will share your hardware
• Capacity Reservations - reserve capacity in a specific AZ for any duration

EC2 On Demand

• Pay for what you use:Linux or Windows - billing per second, after the first minuteAll other operating systems - billing per hour
• Has the highest cost but no upfront payment
• No long-term commitment
• Recommended for short-term and un-interrupted workloads, where you can't predict how the application will behave

EC2 Reserved Instances

• Up to 72% discount compared to On-demand
• You reserve a specific instance attributes (Instance Type, Region, Tenancy, OS)
• Reservation Period - 1 year (+discount) or 3 years (+++discount)
• Payment Options - No Upfront (+), Partial Upfront (++), All Upfront (+++)
• Reserved Instance's Scope - Regional or Zonal (reserve capacity in an AZ)
• Recommended for steady-state usage applications (think database)
• You can buy and sell in the Reserved Instance Marketplace
• Convertible Reserved InstanceCan change the EC2 instance type, instance family, OS, scope and tenancy Up to 66% discount

EC2 Savings Plans

• Get a discount based on long-term usage (up to 72% - same as Rls)
• Commit to a certain type of usage ($ 10/hour for 1 or 3 years)
• Usage beyond EC2 Savings Plans is billed at the On-Demand price
• Locked to a specifc instance family & AWS region (e.g., M5 in us-east-1)
• Flexible across:Instance Size (e.g., m5.xlarge, m5.2xlarge)OS (e.g., Linux, Windows)Tenancy (Host, Dedicated, Default)

EC2 Spot Instances

• Can get a discount of up to 90% compared to On-demand
• Instances that you can "lose" at any point of time if your max price is less than the current spot price
• The MOST cost-efficient instances in AWS
• Useful for workloads that are resilient to failureBatch jobsData analysislmage processingAny distributed workloadsWorkloads with a flexible start and end time
• Not suitable for critical jobs or databases

EC2 Dedicated Hosts

• A physical server with EC2 instance capacity full dedicated to your use
• Allows you address compliance requirements an d use your existing server-bound software licenses (per-socket, per-core, pe-VM software licenses)
• Purchasing Options:On-demand - pay per second for active Dedicated HostReserved - 1 or 3 years (No Upfront, Partial Upfront, All Upfront)
• The most expensive option
• Useful for software that have complicated licensing model (BYOL - Bring Your Own License)
• Or for companies that have strong regulatory or compliance needs

EC2 Dedicated lnstances

• Instances run on hardware that's dedicated to you
• May share hardware with other instances in same account
• No control over instance placement (can move hardware after Stop/Start)

EC2 Capacity Reservations

• Reserve On-Demand instances capacity in a specifc AZ for any duration
• You always have access to EC2 capacity when you need it
• No time commitment (create/cancel anytime), no biling discounts
• Combine with Regional Reserved Instances and Savings Plans to benefit from billing discounts
• You're charged at On-Demand rate whether you run instances or not
• Suitable for short-term, uninterrupted workloads that needs to be in a specific AZ

Which purchasing option is right for me?

• On demand: coming and staying in resort whenever we like, we pay the full price
• Reserved: like planning ahead and if we plan to stay for along time, we may get a good discount
• Savings Plans: pay a certain amount per hour for certain period and stay in any room type (e.g., King, Suite, SeaView, ...)
• Spot instances: the hotel allows people to bid for the empty rooms and the highest bidder keeps the rooms. You can get kicked out at anytime
• Dedicated Hosts: We book an entire building of the resort
• Capacity Reservations: you book a room for a period with full price even you don't stay in it

Price Comparison Example - m4.large - us-east-1

Spot Instances & Spot Fleet

EC2 Spot Instance Requests

• Can get a discount of up to 90% compared to On-demand
• Define max spot price and get the instance while current spot price < maxThe hourly spot price varies based on offer and capacityIf the current spot price > your max price you can choose to stop or terminate your instance with a 2 minutes grace period.
• Other strategy: Spot Block"block" spot instance during a specified time frame (1 to 6 hours) without interruptions In rare situations, the instance may be reclaimed
• Used for batch jobs, data analysis, or workloads that are resilient to failures
• Not great for critical jobs or databases

EC2 Spot Instances Pricing

How to terminate Spot Instances?

Spot Fleets

• Spot Fleets = set of Spot Instances + (optional) On-Demand Instances
• The Spot Fleet will try to meet the target capacity with price constraints Define possible launch pools: instance type (m5.large), OS, Availabilty Zone Can have multiple launch pools, so that the fleet can chooseSpot Fleet stops launching instances when reaching capacity or max cost
• Strategies to allocate Spot Instances:lowest Price: from the pool with the lowest price (cost optimization, short workload)diversified: distributed across all pools (great for availability, long workloads)capacityOptimized: pool with the optimal capacity for the number of instances
• Spot Fleets allow us to automatically request Spot Instances with the lowest price