CentOS 7升级到CentOS 8 Stream

# yum update -y
# yum install -y epel-release
# yum install -y yum-utils rpmconf
# rpmconf -a
# package-cleanup --leaves
# package-cleanup --orphans
# yum install -y dnf
# dnf -y remove yum yum-metadata-parser
# rm -Rf /etc/yum
# dnf upgrade -y
# dnf install http://mirror.centos.org/centos/8/BaseOS/x86_64/os/Packages/{centos-linux-release-8.3-1.2011.el8.noarch.rpm,centos-gpg-keys-8-2.el8.noarch.rpm,centos-linux-repos-8-2.el8.noarch.rpm}
# dnf -y upgrade https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm
# dnf clean all
# rpm -e `rpm -q kernel` --nodeps
# rpm -e --nodeps sysvinit-tools
# dnf -y --releasever=8 --allowerasing --setopt=deltarpm=false distro-sync
# dnf -y install kernel-core
# dnf -y groupupdate "Core" "Minimal Install"
# cat /etc/redhat-release
# dnf swap centos-linux-repos centos-stream-repos
# dnf distro-sync