====== AWS EC2 ======

===== SSH 접속 =====
  * [[aws:ssm|AWS SSM]]
  * [[https://aws.amazon.com/ko/blogs/korea/new-using-amazon-ec2-instance-connect-for-ssh-access-to-your-ec2-instances/|Amazon EC2 Instance Connect를 통해 EC2 인스턴스에 대한 SSH 연결하기 | Amazon Web Services 한국 블로그]]


===== Timezone 변경 Time Sync =====
  * https://docs.aws.amazon.com/ko_kr/AWSEC2/latest/UserGuide/set-time.html
  * timezone 을 적당히 변경하고, chrony로 ntp 연동을 해야 한다.


===== CPU Steal Time =====
  * 동일 물리장비내의 다른 가상 서버가 내 가상 서버의 CPU를 점유하는 현상
  * [[http://blog.scoutapp.com/articles/2013/07/25/understanding-cpu-steal-time-when-should-you-be-worried|Understanding CPU Steal Time - when should you be worried?]]
  * [[https://discuss.newrelic.com/t/cpu-steal-in-infrastructure/48374|CPU Steal % in Infrastructure - Support: Products & Agents / New Relic Infrastructure - New Relic Explorers Hub]]
  * [[http://sawadeekab.tistory.com/10|T2 시리즈를 쓸 때 생기는 문제점 (Steal time 해결방법)]]

===== Spot Fleet =====
  * [[https://searchaws.techtarget.com/definition/AWS-Spot-Fleets-Amazon-Web-Services-Spot-Fleets|What is AWS Spot Fleets (Amazon Web Services Spot Fleets)? - Definition from WhatIs.com]]
  * [[https://aws.amazon.com/ko/blogs/korea/new-auto-scaling-for-ec2-spot-fleets/|EC2 Spot Fleets – 신규 자동 스케일링 기능 | Amazon Web Services 한국 블로그]]

===== UnknownHostException =====
  * ''java.net.UnknownHostException: somehostname: somehostname: Name or service not known'' 처럼 localhost 의 hostname 탐색시에 hostname 을 모르겠다는 오류가 발생할 수 있다.
  * ''/etc/hosts'' 에 해당 hostname 을 localhost 와 함께 추가해준다.
  * 일부 IPv6 로 조회하는 경우에 대비해 ''::0'' 같은 IPv6 에도 대응해서 추가해줄 수 있다.

===== 참고 =====
  * [[http://woowabros.github.io/security/2018/06/29/aws-network-mirror.html|AWS에서 서버(EC2) 패킷 미러링 하기 - 우아한형제들 기술 블로그]]
  * [[https://cloudonaut.io/ec2-network-performance-cheat-sheet/|EC2 Network Performance Cheat Sheet | cloudonaut]]
  * [[https://stackoverflow.com/questions/10541363/self-terminating-aws-ec2-instance|amazon ec2 - Self-Terminating AWS EC2 Instance? - Stack Overflow]]
  * [[https://aws.amazon.com/ko/blogs/infrastructure-and-automation/securing-your-bastion-hosts-with-amazon-ec2-instance-connect/|ec2-instance-connect]]
  * [[https://aws.amazon.com/ko/blogs/security/securely-connect-to-linux-instances-running-in-a-private-amazon-vpc/|Securely Connect to Linux Instances Running in a Private Amazon VPC | AWS Security Blog]]