EC2 instance rebooted unexpectedly

Question

Hello,

Instance ID: i-0582a28a46a656e64 in ap-northeast-1 rebooted unexpectedly at 2023-02-15 22:15:35 UTC.

```
$ journalctl --list-boots
-2 f2c39f848342459da7d2a916638583dd Wed 2021-09-01 01:19:10 UTC—Mon 2021-10-18 07:16:17 UTC
-1 bc0fca97974644549d4db7f7400f8191 Mon 2021-10-18 07:16:22 UTC—Wed 2023-02-15 22:06:00 UTC
 0 2821ef65e52940e298c6fa400aef02b7 Wed 2023-02-15 22:15:35 UTC—Thu 2023-02-16 01:34:03 UTC
```

I checked CloudTrail but could not find any event that looked relevant.
Can someone from Amazon check the cause of this reboot?

Thank you.

Answer

Hello,

It would be recommended to open up a case with [AWS Support](https://aws.amazon.com/contact-us/) if at all possible regarding the mentioned EC2 instance so that AWS Support Engineers are able to review your resources in-depth. In general, there is a wide variety of causes for reboots per [this knowledge center article](https://aws.amazon.com/premiumsupport/knowledge-center/ec2-instance-automatic-reboot-cause/).

* The instance failed one or both of its status checks.
* The underlying hardware hosting your instance was faulty and Amazon EC2 restarted the instance to move it to new, healthy hardware.
* Scheduled maintenance occurred on your instance that required a reboot.
* A user or application inside your server rebooted the instance.
* A kernel bug. If you encounter a kernel bug, be sure that your kernel is fully updated.

Resolutions and investigative steps are located within the article. [This article](https://aws.amazon.com/premiumsupport/knowledge-center/ec2-windows-identify-stop-reboot/) also exists for Windows instances specifically.

EC2 instance rebooted unexpectedly

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