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Chapter 16. Installing kdump
The kdump service is installed and activated by default on Red Hat Enterprise Linux installations. You can enable and configure kdump during installation with Anaconda or afterward on the command line.
16.1. What is kdump
kdump provides a crash dumping mechanism that generates a vmcore file for analysis. By using the kexec system call, it boots into a reserved capture kernel without a reboot to save the crashed kernel’s memory to a file.
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.
16.2. Installing kdump using Anaconda
To configure kdump during an interactive installation, use the Anaconda installer’s graphical interface. With this feature, you can enable kdump and reserve the necessary memory.
Procedure
-
On the Anaconda installer, click KDUMP and enable
kdump. - In Kdump Memory Reservation, select Manual` if you must customize the memory reserve.
-
In KDUMP > Memory To Be Reserved (MB), set the required memory reserve for
kdump.
16.3. Installing kdump on the command line
To enable kdump when it is not installed by default, such as in custom Kickstart installations, install the required packages and confirm the installation.
Prerequisites
- An active Red Hat Enterprise Linux subscription.
-
A repository containing the
kexec-tools,kdump-utils, andmakedumpfilepackages for your system CPU architecture. -
Fulfilled requirements for
kdumpconfigurations and targets. For details, see Supported kdump configurations and targets.
Procedure
Check if
kdumpis installed on your system:# rpm -q kexec-tools kdump-utils makedumpfileIf the
kdumpis not installed, install required packages:# dnf install kexec-tools kdump-utils makedumpfile
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