On Sat, 05 Dec 2020 22:35:37 +0900, Joontaek Oh said:
So, I am using my laptop with the multi-booting but it is too space-consuming.
Moreover, I get work that needs to modify the kernel 3.10.0 for Centos, but the kernel 3.10.0 is not installed on the Ubuntu any version, and the kernel 3.10.61 or the kernel 4.18.0 is not installed on Centos.
Instead of installing 2 or 3 entire OSs, why not use grub2 for what it's intended for, and just keep multiple kernels in /boot? A 1 gigabyte /boot will hold 20 or so copies of vmlinuz- and matching initramfs-, allowing you to have a 3.10.0, a 3.10.61, a 4.18.0, a 5.8-5.10 kernel or two, and still have room for a dozen or so builds if you find a need to bisect something. And the *vast* majority of stuff will Work Just Fine even if the kernel version doesn't match the /usr userspace - there's not a lot of programs that actually *use* the new syscalls we've added since 3.10 or so, and glibc will paper over most of the mismatches. Of course, *some* stuff needs to be a match, but those usually require a *precise* uname match - 4.18.9-foo1 and 4.18.9-bar1 aren't matches for that sort of thing, and the version you need is probably in the tools/ subdirectory of the kernel source tree matching the running kernel. If 1 gigabyte is too space consuming, you have *bigger* problems to deal with....