Summary
In this chapter, we reviewed the boot sequence. As you have seen, it is not long, but it is complex. It is also very important as no system can run if it cannot boot. We learned about the main differences between a BIOS-enabled system and a UEFI one, which enables some capabilities but also has its own requirements. Additionally, we learned about GRUB and its important role in the boot sequence, how to modify entries permanently with grubby, and how to make a one-time modification. Now, we understand the main files to boot, such as the kernel, vmlinuz, and the initial RAM disk, initrd.
This chapter also showed us how to start in emergency and rescue modes, as well as how to intervene in a system to reset the root password.
With these tools and procedures, we are now more prepared to handle any difficult situations in our systems. It’s time to dive deeper and learn about kernel tuning and performance profiles in the next chapter.
