Notes for upgrading CentOS7 to CentOS8 in place:

https://www.alessandronuccio.it/2020/10/21/upgrade-centos-7-to-centos-8/

• 'rpm -e `rpm -q kernel`' would fail, try to erase current kernel
• 'dnf –releasever=8 –allowerasing –setopt=deltarpm=false distro-sync' would also fail, trying to remove the current kernel
• Got stuck into kernel dependency issues
• Aborted this track

https://www.centlinux.com/2020/01/how-to-upgrade-centos-7-to-8-server.html

• Had to follow instructions very carefully and ensure to follow every step
• Finally got to a point I could not continue

Tried this but failed:

dnf upgrade http://mirror.centos.org/centos/8/BaseOS/x86_64/os/Packages/{centos-release-8.1-1.1911.0.8.el8.x86_64.rpm,centos-gpg-keys-8.1-1.1911.0.8.el8.noarch.rpm,centos-repos-8.1-1.1911.0.8.el8.x86_64.rpm}

Then tried this:

dnf upgrade 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}

Package centos-linux-release not installed, cannot update it.

No match for argument: /var/cache/dnf/commandline-5fda33494c9fb882/packages/centos-linux-release-8.3-1.2011.el8.noarch.rpm Package centos-gpg-keys not installed, cannot update it. No match for argument: /var/cache/dnf/commandline-5fda33494c9fb882/packages/centos-gpg-keys-8-2.el8.noarch.rpm Package centos-linux-repos not installed, cannot update it. No match for argument: /var/cache/dnf/commandline-5fda33494c9fb882/packages/centos-linux-repos-8-2.el8.noarch.rpm Error: No packages marked for upgrade.

Then did this:

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}

Seemed to work.

Ran dnf –releasever=8 –allowerasing –setopt=deltarpm=false distro-sync

but got this:

Error: transaction check vs depsolve: (gcc >= 8 with gcc < 9) is needed by annobin-9.23-1.el8.x86_64 rpmlib(RichDependencies) ⇐ 4.12.0-1 is needed by annobin-9.23-1.el8.x86_64 (mariadb >= 3:10.3.27 if mariadb) is needed by mariadb-connector-c-3.1.11-2.el8_3.x86_64 (mariadb-connector-c-config = 3.1.11-2.el8_3 if mariadb-connector-c-config) is needed by mariadb-connector-c-3.1.11-2.el8_3.x86_64 rpmlib(RichDependencies) ⇐ 4.12.0-1 is needed by mariadb-connector-c-3.1.11-2.el8_3.x86_64 (mariadb-devel >= 3:10.3.27 if mariadb-devel) is needed by mariadb-connector-c-devel-3.1.11-2.el8_3.x86_64 rpmlib(RichDependencies) ⇐ 4.12.0-1 is needed by mariadb-connector-c-devel-3.1.11-2.el8_3.x86_64 (lightdm-greeter = 1.2 if xorg-x11-server-Xorg) is needed by lightdm-1.30.0-6.el8.x86_64 rpmlib(RichDependencies) ⇐ 4.12.0-1 is needed by lightdm-1.30.0-6.el8.x86_64 (flatpak-selinux = 1.6.2-6.el8_3 if selinux-policy-targeted) is needed by flatpak-1.6.2-6.el8_3.x86_64 rpmlib(RichDependencies) ⇐ 4.12.0-1 is needed by flatpak-1.6.2-6.el8_3.x86_64 (annobin if gcc) is needed by redhat-rpm-config-123-1.el8.noarch rpmlib(RichDependencies) ⇐ 4.12.0-1 is needed by redhat-rpm-config-123-1.el8.noarch To diagnose the problem, try running: 'rpm -Va –nofiles –nodigest'. You probably have corrupted RPMDB, running 'rpm –rebuilddb' might fix the issue. The downloaded packages were saved in cache until the next successful transaction. You can remove cached packages by executing 'dnf clean packages'.

Ran: dnf remove vdo fcoe-utils

rpm -Va –nofiles –nodigest

rpm –rebuilddb

Can't continue.