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Graham Nicholls
Graham Nicholls

Reputation: 561

Changing date/time on an AWS EC2 instance causes the server to beccome unresponsive within about an hour

I have a program which runs on an EC2 instance. The program is is time-driven, and written in go, so to test it, I can't use faketime - I have to change the time on the server. The server is built from the Amazon Linux 2 AMI, with some extra agents, and runs fine in many (100s-1000s of instances) other cases, where the time is not modified. The instance type is an M5a.xlarge.

Google can't find any other instances where people are reporting issues changing time for testing on EC2 linux instances (or my search skills are not up to it).

If I change the time, the server runs OK for upto an hour or so, and then the load-average starts to climb, and it quickly becomes unresponsive.

The server has a single ENI (I did originally write that it had a second, but have simplified by removing that), and is using EFS.

Does anyone have experience setting time forwards on EC2 instances?

Update: having top running is useful as it shows that although the load average is climing, no single process is responsible (as far as I can see) - nothing in the process table is using > 1%

Further update: removing the second ENI makes no difference - at some random but less that around an hour - time, the server becomes unresponsive.

Upvotes: 2

Views: 1031

Answers (1)

yuin
yuin

Reputation: 1

the ec2 may be running into dhcp issue. specifically dhclient unable to renew expired lease on ip address due to time change. see https://access.redhat.com/errata/RHBA-2020:1858 and the referenced bug https://bugzilla.redhat.com/show_bug.cgi?id=1729211

Upvotes: 0

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