Hands-on Lab·Red Hat Certified System Administrator
Boot Loader Configuration
One objective, and the last of the 62. RHEL 10 uses Boot Loader Specification entries, so `grub.cfg` no longer lists kernels and `grubby` is the tool. The capture backs up every boot file before touching anything, because a broken bootloader is the only mistake on this exam that a running machine cannot show you.
Deploy and Maintain Guide 47 of 67 Advanced
- OSRHEL 10.0 (Coughlan)
- Kernel6.12.0-55.9.1.el10_0
- dnf4.20.0
- Flatpak1.16.0
- TimeAbout 15 min
- Reviewed23 August 2026
Written against the versions above. With `GRUB_ENABLE_BLSCFG=true` - the RHEL default - each kernel is a file in `/boot/loader/entries/`. `grub.cfg` contains a `blscfg` directive and no kernel entries, so regenerating it does **not** change kernel arguments, and material that tells you to edit `grub.cfg` directly predates this.
| Server Name | IP Address | OS | Roles | CPU | RAM | HDD |
|---|---|---|---|---|---|---|
| RHCSA-A01 | 192.168.0.31 | RHEL 10.0 (Coughlan) | Practice node (graded) - spare /dev/sda | 2 Core | 4 GB | 50 GB + 15 GB |
Before you start
- A sudo-capable account.
- The session backs up
grub.cfg, the BLS entries and/etc/default/grub, and restores all three. Verify a backup exists before doing any of this on a machine you care about.
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What the bootloader is made of
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BLS is why `grub.cfg` is boring now
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Listing and choosing a kernel
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Adding a kernel argument
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Removing it, and the targeting flags
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The defaults file, and regenerating