Install GRUB on a Linux server - - Alibaba Cloud Documentation Center

Install or upgrade GRUB to v2.02+ for Server Migration Center (SMC) migration to Alibaba Cloud.

Background

SMC requires GRUB v2.02 or later on the source server. Install or upgrade GRUB in the following situations:

GRUB is not installed.
The server runs an early Linux distribution, such as CentOS 5 or Debian 7.
The installed GRUB version is earlier than v2.02.
The "Do Grub Failed" error appears in the log file.

This procedure uses GRUB v2.02 as an example. The steps are the same for other versions, but the source code package differs. Download other versions from Index of /gnu/grub.

Procedure

Check the GRUB version

Log on to the Linux server as the root user.
Check the file paths of GRUB and related tools:
```
which grub
which grub-install
which grub-mkconfig
```
- If any path does not exist, GRUB is not installed or the files are missing. Proceed to install GRUB.
- If all paths exist, back up the files by renaming them, then install the new version:
```
mv /sbin/grub /sbin/grub-old
mv /sbin/grub-install /sbin/grub-install-old
mv /sbin/grub-mkconfig /sbin/grub-mkconfig-old
```
  Note
  After SMC migration, restore the files by renaming them back to their original names.

Install dependencies

Install GRUB dependencies (bison, gcc, make, and flex) based on your operating system.

CentOS or Red Hat Enterprise Linux

yum install -y bison gcc make flex

Debian or Ubuntu

apt-get update && apt-get install -y bison gcc make flex

Install flex

Create the tools folder if it does not exist.

test -d /home/testuser/tools || mkdir -p /home/testuser/tools

Navigate to the tools folder and download the flex package.

cd /home/testuser/tools
wget https://github.com/westes/flex/releases/download/v2.6.4/flex-2.6.4.tar.gz
tar xzf flex-2.6.4.tar.gz

Compile and install flex, then create a symbolic link.

cd flex-2.6.4
mkdir -p build
cd build
../configure
make && make install
ln -s /usr/local/bin/flex /usr/bin/flex

Install GRUB

Download and decompress the GRUB v2.02 package.

cd /home/testuser/tools
wget https://alpha.gnu.org/gnu/grub/grub-2.02~rc1.tar.gz
tar xzf grub-2.02~rc1.tar.gz

Compile and install GRUB, then create symbolic links.

cd grub-2.02~rc1
mkdir -p build
cd build
../configure
# If the -Werror error is reported, modify the Makefile file and remove the -Werror option from the file. 
sed -i -e "s/-Werror//" ./grub-core/Makefile
sed -i -e "s/-Werror//" ./Makefile
make && make install
ln -s /usr/local/sbin/grub-install /sbin/grub-install
ln -s /usr/local/sbin/grub-mkconfig /sbin/grub-mkconfig

Verify the installation

Verify that GRUB v2.02 is installed:

grub-install --version

Next steps

After GRUB v2.02 is installed, use SMC to migrate the server to Alibaba Cloud. See Server migration guide.

(Optional) To restore the previous GRUB version after migration, run the following commands:

rm /sbin/grub-install
rm /sbin/grub-mkconfig
rm /boot/grub/grub.cfg
mv /sbin/grub-old /sbin/grub
mv /sbin/grub-install-old /sbin/grub-install