How to install Grub on Ubuntu Server?

Question

GRUB

Problem with BIOS/UEFI

reboot and select proper boot device

Q1900M motherboard
I want to install Ubuntu Server, then Asterisk and TeamSpeak server.
Help me solve the issue via ssh [email protected]
At the moment I can’t figure out how to make a bootloader, or how to install ubuntu correctly?

Answer 1

The problem was with the q1900m
motherboard. I disconnected the SSD and connected it to another PC, everything worked, except for the network card - I just can’t figure out who is responsible for dhcp / static in ubuntu server 20.04
. Installed through another computer in the legacy BIOS => then there was a problem with the network card settings.
returned to q1900m chose the USB item instead of EFI USB the system went to install in legacy mode, but sometimes I got a Reed error and after 10 attempts the system was installed - there was a problem with setting up the network card

[email protected]:~# systemctl status network-manager
Unit network-manager.service could not be found.
[email protected]:~#

I can’t find in Google who is responsible for the network interface for setting up in Ubuntu Server 20.04
ANSWER:
For q1900m, installing Ubuntu via legacy + CSM

Answer 2

To install the uefi bootloader, you need to run the livecd version of linux in uefi mode , then mount the operating system partitions from the console (the root / /boot and the main /boot/EFI are important, I remind you that for UEFI to work you need a partition with a fat32 EFI bootloader about 100mb in size) and execute
grub-install --root-directory=/mnt /dev/sda
where / mnt is the root of the system, and / dev / sda is the device on which the / efi partition is located (by the way, in UEFI mode, the partition is not needed, since the boot sector is no longer used, but I somehow indicated it without a partition, it gave me error, I didn’t dig)
grub itself will analyze the structure of the partitions used, install the efi bootloader on the disk and run efibootmgr which will update the table in the BIOS. Of course, you can start everything yourself without grub, but it's easier with it.
ps /boot of the system must be in a file system that grub knows about (for example, it does not know bcache), and in simple cases like btrfs/ext4/... at the root, the /boot partition is not needed at all.
If you need legacy mode, then grub-install needs to specify the partition where the bootloader is to be installed, and if it is a disk with gpt markup, then there should be a bios boot partition (1mb)
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upd. if --root-directory does not work (it happened to me once, either the OS version was exotic or for some other reason), then you need to mount in addition to all the OS directories in /mnt, also /dev /sys /proc/ and /run using mount -o bind /dev /mnt/dev ..., then chroot /mnt there and run grub-install /dev/sda from it and it seems that /mnt/etc/mtab also needs to be edited (generally a dreary way)