Kdump is a reliable Kernel Crash Dumping Mechanism, in which a crash dump is captured by a second kernel (crash kernel) booted when the main kernel crashes.
This second kernel (crash kernel) uses a small amount of memory for booting and capturing the dump image (vmcore) file. The part of memory reserved by the main kernel is used by the second kernel to boot. Preserving the main kernel’s crash dump is a result of kexec mechanism which allows to boot the second kernel without the necessity of rebooting the system and passing through BIOS procedures.
The time for capturing the vmcore file depends on the amount of the occupied memory during crash. The average time of capturing a 5GB vmcore file is approximately 20-25 minutes.
When the kdump is successfully made during the system crash, a vmcore file is created in a dump location (usually /var/crash/ directory) and next the system reboots. After crash the vmcore file should be analyzed to determine root cause of the failure.
Below we present how to configure and manage kdump service on CentOS 7 / RHEL 7.
Continue reading “Manage and Configure Kdump Service on CentOS 7 / Red Hat 7”
Puppet is an open-source configuration management tool written in Ruby by Luke Kanies which includes its own declarative language to describe system configuration.
In this tutorial we install and configure Puppet on CentOS 7 based hosts.
Continue reading “Setup Puppet Master and Multiple Agents on CentOS 7”
Xfce is a free and open-source desktop environment for Unix and Unix-like platforms which aims to be fast, intuitive, user-friendly and lightweight, while still being visually attractive for user.
In the below short tutorial we will install Xfce 4 Desktop Environment on CentOS 7 system in few steps.
Continue reading “Install Xfce 4 Desktop Environment on CentOS 7”
KVM (Kernel-based Virtual Machine) is a virtualization infrastructure for the Linux which requires a processor with hardware virtualization extension to be able to host guest sytems. KVM is convenient solution to test and try different operating systems if you don’t have a possibility to purchase expensive and power consuming physical hardware.
The below tutorial presents KVM (QEMU) installation and setup along with Linux Bridge configuration on CentOS7 / RedHat7 operating system.
Continue reading “Install and Configure KVM (Bridge Net Interface) on CentOS 7 / RHEL 7”