Red Hat Summit14장. Installing kdump
The kdump service is installed and activated by default on the Red Hat Enterprise Linux installations.
14.1. What is kdump
kdump is a service that provides a crash dumping mechanism and generates a crash dump or a vmcore dump file. vmcore includes the contents of the system memory for analysis and troubleshooting. kdump uses the kexec system call to boot into the second kernel, capture kernel, without a reboot. This kernel captures the contents of the crashed kernel’s memory and saves it into a file. The second kernel is available in a reserved part of the system memory.
A kernel crash dump can be the only information available if a system failure occur. Therefore, operational kdump is important in mission-critical environments. You must regularly update and test kexec-tools, kdump-utils, and makedumpfile packages in your normal kernel update cycle. This is important when you install new kernel features.
If you have multiple kernels on a machine, you can enable kdump for all installed kernels or for specified kernels only. When you install kdump, the system creates a default /etc/kdump.conf file. /etc/kdump.conf includes the default minimum kdump configuration, which you can edit to customize the kdump configuration.
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