Howto migrate centos7 to 8x

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rhel alternatives or derivatives:

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

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

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