Who Has Rebooted The Linux System?

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. 

What or Why DNF?

DNF or Dandified YUM is the next generation version of yum. 

DNF is a software package manager that installs, updates, and removes packages on RPM-based Linux distributions. It automatically computes dependencies and determines the actions required to install packages. DNF also makes it easier to maintain groups of machines, eliminating the need to manually update each one using rpm. Introduced in Fedora 18, it has been the default package manager since Fedora 22. So, in this post I’m not going to discuss the usage of DNF rather on why and advantages of using it. By default, DNF comes pre-installed on RHEL8.x releases. The "yum" command is a symbolic link to the "dnf" binary now.

Different Fault Tolerance Options At System/Patch Level In Linux

 

As we all know, patching is an essential & integral part of any IT infrastructure. It could be cloud based systems (virtual) or an on-premise virtual systems or physical servers running in a dedicated data center. Patch management has now become an important buzzword in corporate IT organizations and business offices. Patch management is basically the process of acquiring, testing and installing multiple code changes (patches) to systems software and applications.