Howto migrate centos7 to 8x

centos7 to 8

rhel alternatives or derivatives:

• rockylinux
• almalinux
• openeuler
• springdale

cloud images:

https://wiki.vidalinux.org/index.php/Linux_cloud_images

distributions to migrate supported:

• CentOS 7 to AlmaLinux 8
• CentOS 7 to Rocky Linux 8
• CentOS 7 to Oracle Linux 8
• CentOS 7 to CentOS Stream 8

update centos7 repos to use vault.centos.org:

sed -i -e '/^mirrorlist/d;/^#baseurl=/{s,^#,,;s,/mirror,/vault,;}' /etc/yum.repos.d/CentOS*.repo

update to latest packages:

yum update -y 

verify your current version:

cat /etc/centos-release

install elevate-release package:

yum install http://repo.almalinux.org/elevate/elevate-release-latest-el7.noarch.rpm -y

install leapp-upgrade and migration-data:

Possible options are:

• leapp-data-almalinux
• leapp-data-centos
• leapp-data-oraclelinux
• leapp-data-rocky

yum install leapp-upgrade leapp-data-almalinux -y

install networkmanager is not installed:

yum install NetworkManager -y

enable and start networkmanager:

systemctl enable NetworkManager && systemctl start NetworkManager

disable selinux on /etc/default/grub add the following:

GRUB_CMDLINE_LINUX="console=tty0 crashkernel=auto net.ifnames=0 biosdevname=0 console=ttyS0 selinux=0"

update grub config:

grub2-mkconfig -o /boot/grub2/grub.cfg

start a preupgrade check:

leapp preupgrade

normally the check will fail, it’s normal because we need to do some tweaks:

modprobe -r btrfs
rmmod pata_acpi
echo PermitRootLogin yes | sudo tee -a /etc/ssh/sshd_config
leapp answer --section remove_pam_pkcs11_module_check.confirm=True

then run check again:

leapp preupgrade

if everything runs well, upgrade the system:

leapp upgrade

once the migration is completed, you’ll be offered to reboot the system:

reboot

select the new entry in grub called ELevate-Upgrade-Initramfs, wait for the upgrade process to finish.

when system is migrated to el8 run the following command to remove any el7 rpm package:

rpm -qa|grep el7|xargs rpm -e

centos8 to almalinux8

fix mirrors:

sed -i -e '/^mirrorlist/d;/^#baseurl=/{s,^#,,;s,/mirror,/vault,;}' /etc/yum.repos.d/CentOS*.repo

update your system to latest:

yum update -y

download deploy script:

curl -O https://raw.githubusercontent.com/AlmaLinux/almalinux-deploy/master/almalinux-deploy.sh

fix script permissions:

chmod +x almalinux-deploy.sh

run the script:

bash almalinux-deploy.sh

if an error ocurrs with signatures do the following:

rpm --import https://repo.almalinux.org/almalinux/RPM-GPG-KEY-AlmaLinux

almalinux8 to almalinux9

• https://wiki.almalinux.org/elevate/ELevate-testing-guide.html

rocky8 to rocky9

install rocky-release, rocky-repos, and rocky-gpg-keys:

VERSION=9.5-1.3
REPO_URL="https://download.rockylinux.org/pub/rocky/9/BaseOS/x86_64/os/Packages/r"
RELEASE_PKG="rocky-release-${VERSION}.el9.noarch.rpm"
REPOS_PKG="rocky-repos-${VERSION}.el9.noarch.rpm"
GPG_KEYS_PKG="rocky-gpg-keys-${VERSION}.el9.noarch.rpm"
dnf install -y $REPO_URL/$RELEASE_PKG $REPO_URL/$REPOS_PKG $REPO_URL/$GPG_KEYS_PKG

remove unneccesary packages:

dnf -y remove rpmconf yum-utils epel-release
rm -rf /usr/share/redhat-logos

install rocky9 packages:

dnf -y --releasever=9 --allowerasing --setopt=deltarpm=false distro-sync

if upgrade got stock upgrading auditd:

ps aux | grep [a]udit
kill -9 <pid>

when package installation finish recreate rpmdb:

rpm --rebuilddb

reboot system:

reboot

remove all el8 rpms:

rpm -qa|grep el8|xargs rpm -e

remove all modules:

dnf module disable "*" -y

remove all old gpg keys:

rpm -e `rpm -qa | grep gpg-pubkey | xargs`

references

• https://wiki.almalinux.org/elevate/ELevate-quickstart-guide.html