ec2 instance rebooted by itself

Question

Hi,

Our instance(i-0acf52896afa35c0f) August 25 morning 08:29 (UTC+8) after the automatic restart is still inaccessible, We restored it to normal at 08:36 after a manual reboot at the console, but the system log(/var/log/message,dmesg) found no errors.

```
>last reboot
reboot   system boot Thu Aug 25 08:36 - 17:05 (5+08:28)   
reboot   system boot Thu Aug 25 08:29 - 17:05 (5+08:35) 
```

```
# /var/log/message snippet
Aug 25 08:20:34 ip- nm-dispatcher: req:1 'dhcp4-change' [eth0]: start running ordered scripts...
Aug 25 08:22:28 ip- dhclient[471465]: DHCPDISCOVER on docker0 to 255.255.255.255 port 67 interval 3 (xid=0x343ac688)
Aug 25 08:22:31 ip- dhclient[471465]: DHCPDISCOVER on docker0 to 255.255.255.255 port 67 interval 5 (xid=0x343ac688)
Aug 25 08:22:36 ip- dhclient[471465]: DHCPDISCOVER on docker0 to 255.255.255.255 port 67 interval 7 (xid=0x343ac688)
Aug 25 08:22:43 ip- dhclient[471465]: DHCPDISCOVER on docker0 to 255.255.255.255 port 67 interval 18 (xid=0x343ac688)
Aug 25 08:22:57 ip- dhclient[471465]: DHCPREQUEST on eth0 to x.x.x.x port 67 (xid=0x71963ea7)
Aug 25 08:22:57 ip- dhclient[471465]: DHCPACK from x.x.x.x (xid=0x71963ea7)
Aug 25 08:36:41 ip- journal: Runtime journal is using 8.0M (max allowed 743.7M, trying to leave 1.0G free of 7.2G available â†’ current limit 743.7M).
Aug 25 08:36:41 ip- kernel: Initializing cgroup subsys cpuset
Aug 25 08:36:41 ip- kernel: Initializing cgroup subsys cpu
Aug 25 08:36:41 ip- kernel: Initializing cgroup subsys cpuacct
```

We found a instance and system status check error in cloudwatch starting at 08:24.

CloudTrail only has records of our manual restart instances at 08:36.

I would really appreciate some help.

Tariro S · Accepted Answer

System Status checks indicate that there was a hardware failure on the host that your instance was running on (AWS end). Stop starting the instance moves it away from the faulty hardware to a healthy host, basically each stop starts moves the instance to a different host. EC2 now has an automated service that does this and it had already triggered a stop start when you were rebooting on the console, and the stop start is what actually migrated the instance to a healthy host.

You can read more about System status checks below: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/monitoring-system-instance-status-check.html#types-of-instance-status-checks

You can read more about System status checks below:
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/monitoring-system-instance-status-check.html#types-of-instance-status-checks

ec2 instance rebooted by itself

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