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I was working on the mirroring of an EC2 instance. I followed these steps

  1. create an image(AMI) of the instance you would like to mirror
  2. Launch an instance out of the image
  3. ssh into the new instance and launch the processes

The new instance worked like a charm.

I also tried the another method.

  1. Create a snapshot of an instance
  2. Create an image from snapshot
  3. Try and launch the instance from the image.

But somehow the server is not getting set up properly and it fails the status checks built in Amazon console. I need to figure out the reason as it may be critical at some point to be able to launch a server from the snapshot.

2 Answers 2

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The most common cause of the scenario you describe is a failure to specify the correct kernel (AKI) when registering the snapshot as an AMI.

Compare the AKI of the AMI that works with the AKI of the AMI that does not work.

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  • Thank you. It was that the kernel ID was not correct
    – ranjith
    May 2, 2012 at 4:50
  • Thank you soooooooo much!!! I have wasted hours with this...
    – Rafa
    May 7, 2012 at 15:28
  • If the original instance is gone and you only have the snapshot, how do you determine the AKI? Any automated way to store the AKI-id in the snapshot description or as a tag? Can ec2-consistent-snapshot do this? Aug 13, 2014 at 15:07
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    @martijnheemels I think most PV AMIs have been using the same PV AKI. Yes, snapshots can have tags, and ec2-consistent-snapshot can add tags, but why not register snapshot as an AMI at create time? Shouldn't add any cost over the snapshot itself. Aug 31, 2014 at 6:24
  • @EricHammond We create daily snapshots of multiple volumes on a dozen instances. We rarely need to recover from one. I suppose I thought having so many AMI's would be hell to maintain and clean up. Good idea though. Any suggestions on how to automate such a system? Sep 1, 2014 at 14:38
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Just to add to the answer:

You can troubleshoot boot issues by viewing the system log. You can do this in the AWS console on the EC2 tab by selecting the instance and clicking 'Instance Actions' > 'Get System Log'.

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  • My System Log never got generated... :-(
    – Rafa
    May 7, 2012 at 15:27
  • FYI: The system log sometimes takes a while to appear as available in the console. I've had it take up to 30. Jun 27, 2012 at 3:12

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