There are many times that we get puzzled with this question "Who has rebooted the system?". Was this triggered by a user or done by some kernel threads? What was the reason why the server was rebooted? Of course, a running system should not be rebooted without a reason, as this incurs downtime and service disruptions. There are many ways to avoid service disruption by setting up High Availability (HA) so that one server down/reboot would not cause any downtime as the application/service would continue to work from another server in this setup. However, in Load Balancer (LB) mode where there are multiple nodes serving the applications and node down would certainly be balanced by other nodes in the LB setup. Let's come back to our main agenda which is to track the system reboot activity. Yes, in this blog post we would talk about this topic and different ways to detect/identify this from a Linux system.