When using aws s3 cp to copy files over to s3, fails due to "Could not connect to the endpoint URL", but inconsistent


Hi, I'm using aws cli and boto3 in Linux ubunto 20.4 locally and encountered similar problems. Once in a while, the upload started and I get an upload fail......Could not connect to the endpoint URL......during the uploading

I've been uploading files with various sizes (100s MB to several GB). and followed the self-check in the post

The ping stat is as following

--- s3.amazonaws.com ping statistics ---
491 packets transmitted, 435 received, 11.4053% packet loss, time 491274ms
rtt min/avg/max/mdev = 221.863/234.481/316.978/11.746 ms

However, I was monitoring the internet at the same time. There was no disconnection and my other computer under the same network also seems to be fine. It only happens to AWS.

Is this something related to stability and anything I can check to improve the situation. TIA

2 Answers

Would it be possible for you to share the actual command or code that you executed?
If sometimes it succeeds, but sometimes it fails, it could be a problem around the network.

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answered 9 days ago
  • sure, the actual code is just aws s3 cp <local-file-dir> <s3-dir>

  • Thanks for sharing. There did not seem to be anything wrong with the commands themselves. If you add "--debug" to the command options, you can check the debug log and possibly find something that will help you resolve the error.

    aws s3 cp <local-file-dir> <s3-dir> --debug

The internet is a big place; there are likely many networks between your computer and AWS. It's possible that there is a problem with an AWS service (S3 in this case) but it's also possible that there is packet loss on a network between you and AWS that is causing the problem. You may not see packet loss to other destinations because the path to there is different; you may also be crossing a network that is rate limiting traffic to or from AWS. It's very difficult to tell because all of those networks are controlled by different entities.

If this is an ongoing issue and it is detrimental to your usage of AWS, please create a support case so that the team can investigate.

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answered 9 days ago
  • thx. Is there a way I can pin point down which steps in that whole process just roughly?

  • You might try running a tool like MTR - it provides (somewhat) real-time statistics on the path between you and a destination - think of it as "traceroute on steroids". It's still not perfect because packet loss is not always related to path detection/testing. But it's something.

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