My Tech Blog (Amazon)

1. Cross-Zone Load Balancing교차 영역 로드 밸런싱은 로드 밸런서가 가용 영역(AZ)에 상관없이 모든 인스턴스에 트래픽을 균등하게 분배하는 기능이다. 예를 들어, 한쪽 가용 영역에 EC2 인스턴스 2개, 다른 쪽 가용 영역에 8개가 있다면, 일반적으로 트래픽은 인스턴스 개수에 따라 나뉜다. 하지만 교차 영역 로드 밸런싱을 사용하면, 모든 인스턴스가 동일한 양의 트래픽을 받는다.With Cross Zone Load Balancing:each load balancer instance distributes evenly  across all registered instances in all AZ작동 방식클라이언트가 로드 밸런서(ALB)에 트래픽을 보낸다.각 로드 밸런서 인스턴스는 모든 가용..

1. Sticky Sessions (Session Affinity)고정 세션 또는 세션 밀접성It is possible to implement stickiness so that the same client is alwyas redirected to the same instance behind a load balancerThis works for Classic Load Balancers & Application Load BalancersThe "cookie" used for stickiness has an expiration date you control Use case: make sure the user doesn't lose his session dataEnabling stickiness may bri..

1. Gateway Load Balancer■ deploy, scale, and manage a fleet of 3rd party network virtual appliances in AWS배포 및 확장과 AWS의 타사 네트워크의 가상 어플라이언스 플릿 관리에 사용된다.■ Example: Firewalls, Intrusion Detection and Prevention Systems, Deep Packet Inspection Systems, payload manipulationGWLB의 역할은 트래픽을 방화벽이나 침입 탐지 시스템(어플라이언스)로 전달하는 것이다.■ Operates at Layer 3 (Network Layer) - IP Packets 모든 로드 밸런서보다 낮은 수준에서 실행된다. - I..

1. Network Load Balancer (v2)Network load balancers (Layer 4) allow to:- Forward TCP & UDP traffic to your instances  - Handle millions of request per seconds- Less latency ~100 ms (vs 400 ms for ALB)NLB has one static IP per AZ, and supports assigning Elastic IP(helpful for whitelisting specific IP)NLB are used for extreme performance, TCP or UDP trafficNot included in the AWS free tier시험문제에 고성..

1. Application Load Balancer (v2)Application load balancers is Layer 7 (HTTP)Load balancing to multiple HTTP applications across machines (target groups)Load balancing to multiple applications on the same machine (ex: containers)(동일 EC2 인스턴스 상의 여러 애플리케이션에 부하를 분산한다)Support for HTTP/2 and WebSocketSupport redirects  (from HTTP to HTTPS for exampleALB are a great fit for micro services & container-..

1. Scalability & High AvailabilityScalability(확장성) means that an application / system can handle greater loads by adapting.There are two kinds of scalability  - Vertical Scalability - Horizontal Scalability (=elasticity) 탄력성, 수평 확장성Scalability is linked but different to High Availability ( 확장성 != 고가용성)2. Vertical Scalability - 수직 확장성Vertically scalability means increasing the size of the instanc..

1. The most likely reason your team member is unable to attach the EBS volume to an EC2 instance `in us-east-1b` is that EBS volumes are tied to a specific Availability Zone (AZ) upon creation. Since the volume was originally attached to an EC2 instance in us-east-1a, it is restricted to that AZ and cannot be directly attached to an instance `in us-east-1b`. us-east-1a에서의 EC2 인스턴스를 종료하여, 이 인스턴스에..

EBS vs EFS1. EBS(Elastic Block Storage)▶EBS volumesOne instance (except multi-attach io1 / io2) - 한 번에 하나의 인스턴스만 연결are locked at the Availability Zone (AZ) levelgp2: IO increases if the disk size increasesgp3 & io 1: can increase IO independently▶To migrate an EBS volume across AZTake a snapshotRestore the snapshot to another AZEBS backups use IO and you shouldn't run them while your application..