I am trying to create a bucket 'MyBucket' but I can't. It says bucket with the same name already exists but I could not see any such in my account!

When you try to create a bucket with a name MyBucket (or whatever name), sometimes you would get the following error:

deploy-doc-store-s3 already exists and you will not be able to create the bucket. You would search for that bucket in your account but still you would not find it! Then, why are you not able to create MyBucket when a bucket with the same name does not exist in your account?

This is because S3 is global. AWS S3 does not require region selection. So, S3 Bucket names need to be globally unique. It occurred because someone else would have created a bucket with the name MyBucket.

How to confirm if there already exists a bucket with the name MyBucket?

Run the following command:

aws s3api head-bucket --bucket MyBucket

If it returns,

NOTHING i.e, 200 OK - the bucket already exists and you have access to it (the bucket exists in your current account)

403 Forbidden -  the bucket already exists and you don't have access to it  (the bucket exists in another account)

404 Not Found -  the bucket does not exist

If you get 404, you can create a bucket with that name otherwise you can't.