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Ansible Role linuxfabrik.lfops.kdump

kdump is the Linux kernel crash-dump mechanism: when the running kernel panics, a pre-loaded "capture kernel" boots and writes a vmcore file to disk for post-mortem analysis. The capture kernel needs RAM permanently reserved at boot via the crashkernel= cmdline option, which is wasted on most production servers. By default this role stops and disables kdump.service so the daemon no longer runs; set kdump__service_enabled: true to turn kdump on instead. The crashkernel= reservation itself is not touched, see "How the Role Behaves".

Available since LFOps 2.0.0.

How the Role Behaves

  • When kdump is to run, meaning kdump__service_enabled: true or a kdump__service_state other than stopped, the role installs the package that ships kdump.service: kdump-utils on RHEL 10, kexec-tools on RHEL 8 and 9. With kdump off it installs nothing, and a host without the unit counts as having kdump off already.
  • When kdump is to run and its service cannot be managed, the run fails.
  • kdump only starts once memory is reserved for the capture kernel with crashkernel= on the kernel command line, and a reservation takes effect at the next boot. The role does not set it. Either run kdumpctl reset-crashkernel --kernel=ALL once, which writes the distribution's default, or set crashkernel through bootloader__cmdline_options__host_var / bootloader__cmdline_options__group_var of the bootloader role, then reboot. Until then, starting kdump fails.

Tags

kdump

  • Installs the kdump package when kdump is to run, and manages the state of kdump.service.
  • Triggers: none.

Optional Role Variables

kdump__service_enabled

  • Enables or disables the kdump service, analogous to systemctl enable/disable.
  • Type: Bool.
  • Default: false

kdump__service_state

  • Changes the state of the kdump service, analogous to systemctl start/stop/restart/reload. Possible options:

    • started
    • stopped
    • restarted
    • reloaded

  • Type: String.

  • Default: 'stopped'

Example:

# optional
kdump__service_enabled: false
kdump__service_state: 'stopped'

License

The Unlicense

Author Information

Linuxfabrik GmbH, Zurich