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Instance ID uniqueness

0

I would like to get some clarifications on the uniqueness of Instance IDs. From the docs (https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/resource-ids.html) it says: "we assign each resource a unique resource ID."

I just want to clarify the following:

  • If an instance is terminated, can that Instance ID be used again in the same AWS account?
  • Are Instance IDs unique across all regions in the same AWS account?
Topics
Compute
Tags
Amazon EC2
Language
English
idris
asked a year ago756 views
1 Answer
0
Accepted Answer

Instance IDs are uniquely generated globally, which means for every region and for every account, and are unable to be reused again. So to answer your questions specifically:

  1. No, that same ID cannot be used again.
  2. Yes, and even across all accounts.
profile pictureAWS
Lawrence Aiello
answered a year ago
profile pictureAWS
EXPERT
Jonathan_D
reviewed a year ago
  • idris
    a year ago

    Great, thank you for clarifying

  • Danish Tamboli SUPPORT ENGINEER
    2 days ago

    Just curious. How does the service(Not just for Instances and not just EC2) manage to create a globally unique IDs every single time?

    Lets say there's a small service somewhere doing this job of generating IDs that are unique. Does this service have to look at all the previously used IDs before returning a new one? If Yes, how does it do this so fast? OR Does it simply apply some transformations to a set of known values such as [AccountID, Region, CreationTimestamp, etc.] and hope for the output to be globally unique? OR Is there some other magic happening. (PS: I have no experience with development)

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