New instance from AMI results in Waiting for meta-data accessibility

Question

I've got some right-sizing coming up this weekend and wanted to practice the it before I did it because of a lack of experience. Now, my test has failed and I'm bewildered.

I've got an AMI image, I've made a new instance from it (with a different instance type to the original), but it's failing the instance reachability check because the console says it's waiting for meta-data accessibility.

I've tried adding a new network interface to it, which is what something online suggested.

I've found this: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/common-messages.html#metadata-unavailable

I refuse to believe that THAT much pfaff is necessary - detaching the primary disk, attaching it to a new instance, doing a RegEdit on some information and then putting it back! Seems extraordinary. I would've thought instantiating a new instance from an AMI is a basic thing?

Hope someone can help! :-/

re:Post Agent · Answer

The issue you're experiencing with the "Waiting for meta-data accessibility" error when creating a new instance from an AMI with a different instance type is not uncommon, but it can be frustrating. This error typically occurs when the instance is unable to retrieve its metadata, which is crucial for proper initialization.

While the solution you found involving detaching and reattaching disks is a valid approach for some scenarios, you're right that it shouldn't be necessary for a basic AMI instantiation. Here are some less drastic steps you can try:

1. Ensure compatibility: Verify that the AMI you're using is compatible with the new instance type. Some AMIs may not support certain instance types, especially if there's a significant change in architecture or virtualization type.

2. Check network configuration: Make sure the new instance is in a public subnet with a route to an Internet Gateway and has a public IP address assigned. Also, verify that the VPC, subnet, and route table configurations are correct.

3. Review security groups: Although you've likely already done this, double-check that the security groups allow the necessary inbound and outbound traffic.

4. Examine system logs: Look at the system logs in the EC2 console for any error messages that might provide more insight into the issue.

5. Try EC2 Instance Connect: This method doesn't rely on your local SSH key and might work even if traditional SSH is failing.

6. Consider OS-level firewall: The AMI might have captured a state where the OS-level firewall was configured to block incoming connections. You may need to modify these settings.

If none of these steps resolve the issue, you might want to try creating another new instance in a different subnet or VPC to isolate the problem. As a last resort, you can stop and start the instance, which will migrate it to a new host. Be aware that this will change the public IP address if you're not using an Elastic IP.

Remember to make changes one at a time and test after each modification to identify which change resolves the issue. If the problem persists after trying these steps, it may be worth contacting AWS support for more in-depth assistance.  
**Sources**  
[Troubleshoot the "Waiting for the metadata service" error | AWS re:Post](https://repost.aws/knowledge-center/waiting-for-metadata)  
[EC2 instance from Snapshot not accessible | AWS re:Post](https://repost.aws/questions/QUaLMl1CYZS0WPx1izW-c_1A/ec2-instance-from-snapshot-not-accessible)

New instance from AMI results in Waiting for meta-data accessibility

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