jdeathe/kernel-update-with-fast-boot-via-kexec.md

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Kernel Update with Fast-Boot via kexec

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kernel-update-with-fast-boot-via-kexec.md

Kernel Update with Fast Boot via kexec

# <-- NOTE: This represents the command prompt of a root user

Identify the latest installed kernel

# kernel_release_default="$(
  find /boot/ -name "$(
    grubby --default-kernel \
      | sed -r -e 's~^(/boot/)(vmlinuz-[0-9]+).*$~\2~'
  )"* \
  | sort -rg -t. -k 2 -k 3 -k 4 -k 5 -k 6 \
  | head -n1 \
  | sed -r -e 's~^/boot/vmlinuz-~~'
)"

Identify the running kernel

# kernel_release_running="$(
  uname -r
)"

Load new kernel if available and apply with fast-reboot

# if [[ ${kernel_release_default} != ${kernel_release_running} ]]; then \
  kexec --reuse-cmdline --no-checks \
    --load /boot/vmlinuz-${kernel_release_default} \
    --initrd=/boot/initramfs-${kernel_release_default}.img && \
  systemctl kexec; \
fi

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