EC2

EC2 인스턴스

• Elastic Compute Cloud
• AWS에서 제공하는 서버 
• 가상화 환경에서 생성되는 서버. 다양한 운영체제 지원.
• EC2 내부에 있는 저장소는 휘발성 저장소. 종료시 데이터 손실. 이를 방지 하기 위해서는 파일 스토리지 서비스를 이용해야 함

EC2 sizing & configuration options

• OS
• CPU
• RAM
• storage space
  • EBS & EFS (network-attached)
  • EC2 Instance store (hardware)
• Network card : speed of the card, public ip address
• Firewall rules : security group
• Bootstrap script : EC2 User Data
  • 인스턴스가 최초로 시작될 때 EC2 User Data script를 실행. ( 최초 시작시, 단 한 번)
    • 예시) installing updates, installing software ...
  • root user 권한으로 작동.

EC2 Instance Types

• e.g., m5.2xlarge
  • m : instance class
  • 5 : generation
  • 2xlarge : size within the instance class
• General Purpose
  • web servers or code repositories
  • Balance between : 
    • Compute
    • Memory
    • Networking
• Compute Optimized
  • compute-intensive tasks that require high performance processors
    • Batch processing workloads
    • Media transcoding
    • High performance web servers
    • Hight performance computing
    • Scientific modeling & machine learning
    • Dedicated gaming servers
• Memory Optimized
  • Fast performance for workloads that process large data sets in memory
    • High performance, realational/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
• Storage Optimized
  • Great for storage-intensive tasks that require high, sequential read and write access to large data sets on local storage
    • High frequency online transaction processing systems
    • Relational & NoSQL databases
    • Cache for in-memory databases
    • Data warehousing applications
    • Distributed file systems

Security Groups

• fundamental of network security in AWS
• control how traffic is allowed into or out of EC2 Instances
• only contain allow rules
  • reference by IP or by security group
• act as a "firewall"
  • regulate (1) Access to Ports (2) Authorized IP ranges (3) inbound network (4) outbound network
  • All inbound traffic is blocked by default
  • All outbound traffic is allowed by default
• can be attached to multiple instances
• locked down to a region/vpc combination
• good to maintain one seperate security group for SSH access
• not accessible -> security group issue
• connection refused -> application error or not launched

Classic Ports 

• 22 SSH log into a Linux instance
• 21 FTP (File Transport Protocol) upload files into a file share
• 22 SFTP (Secure File Transport Protocol) upload files using SSH
• 80 HTTP
• 443 HTTPS
• 3389 RDP (Remote Desktop Protocol) log into a Window instance

EC2 Instances Purchasing Options

• On-Demand Instances 
  • short workload, un-interrupted workloads, predictable pricing
  • Linux/Windows - billing per second, after the first minute
  • All ohter operating systems - billing per hour
• Reserved ( 1 & 3 yrs)
  • Up to 72% discount compared to On-demand
  • Reserve a specific instance attributes
    • Instance type
    • Region
    • Tenancy
    • OS
  • Reserved Instances - long workloads
  • Convertible Reserved Instances - long workloads with flexible instances
  • Payment Options - No Upfront, Partial Upfront, All Upfront
  • Reserved Instance's Scope
    • Regional
    • Zonal
  • Recommend for steady-state usage applications, database
  • can buy and sell in the reserved instance marketplace
• Savings Plan (1&3 yrs)
  • commitment to an amount of usage, long workload
  • get a discount based on long-term usage (up to 72%)
  • usage beyond EC2 Savings Plans is billed at the On-Demand price
  • locked to a specific instance family & AWS region
  • flexible across:
    • instance size
    • os
    • tenancy 
• Spot Instances
  • short workloads, cheap, can lose instances (less reliable)
  • can get a discount of up to 90% compared to on-demand
  • MOST cost-efficient instances
  • workloads that are resilient to failure
    • batch jobs
    • data analysis
    • image processing
    • any distributed workloads
    • workloads with a flexible start and end time
• Dedicated Hosts
  • book an entire physical server, control instance placement
  • allows you address compliance requirements and use existing server-bound software licenses
  • purchasing options
    • on-demand
    • reserved
  • the most expensive option
  • useful for software that have complicated licensing model or for companies that have strong regulatory or compliance needs
• Dedicated Instances
  • instances run on hardware that's dedicated to you
  • no other customers will share the hardware
    • but, can share in same account
• Capacity Reservations
  • reserve On-Demand instances capacity in a specific AZ for any duration
  • no time commitment (create/cancel anytime), no billing discounts
  • combine with regional reserved instances & saving plans to benefit from biling discounts
  • good for short-term, un interrupted workloads that needs to be in a specific AZ

EC2 Spot Instance Requests

• Get a discount of up to 90% compared to On-demand
• define max spot price
• recommended for
  • bacth jobs
  • data analysis
  • workloads that are resilient to failures

Spot Fleets

• Spot Fleets = set of Spot Instances + On-Demand Instances
• The Spot Fleet will tryt to meet the target capacity with price constraints
• Strategies to allocate Spot Instances
  • lowestPrice
  • diversified
  • capacityOptimized
  • priceCapacityOptimized