In this article, you will learn how to upgrade CentOS 7 to CentOS 8.5 release. The steps described herein do not depict the official upgrade and this should not be applied to a production server yet.
Step 1: Install the EPEL Repository
To start off, install the EPL repository by running:
# yum install epel-release -y
Step 2: Install yum-utils Tools
After successfully installing EPEL, install yum-utils by running the command below.
# yum install yum-utils
Thereafter, you need to resolve RPM packages by executing the command.
# yum install rpmconf # rpmconf -a
Next, perform a clean-up of all the packages you don’t require.
# package-cleanup --leaves # package-cleanup --orphans
Step 3: Install the dnf in CentOS 7
Now install the dnf package manager which is the default package manager for CentOS 8.
# yum install dnf
You also need to remove the yum package manager using the command.
# dnf -y remove yum yum-metadata-parser # rm -Rf /etc/yum
Step 4: Upgrading CentOS 7 to CentOS 8
We are now ready to upgrade CentOS 7 to CentOS 8, but before we do so, upgrade the system using the newly install dnf package manager.
# dnf upgrade
Next, install CentOS 8 release package using dnf as shown below. This will take a while.
# dnf install http://mirror.centos.org/centos/8/BaseOS/x86_64/os/Packages/{centos-linux-repos-8-3.el8.noarch.rpm,centos-linux-release-8.5-1.2111.el8.noarch.rpm,centos-gpg-keys-8-3.el8.noarch.rpm}
Next, upgrade the EPEL repository.
dnf -y upgrade https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm
After successfully upgrading the EPEL repository, remove all the temporary files.
# dnf clean all
Remove the old kernel core for CentOS 7.
# rpm -e `rpm -q kernel`
Next, be sure to remove conflicting packages.
# rpm -e --nodeps sysvinit-tools
Thereafter, launch the CentOS 8 system upgrade as shown.
# dnf -y --releasever=8 --allowerasing --setopt=deltarpm=false distro-sync
Note: If you get errors about conflicting packages, for example in my case there were conflicts about the existing python36-rpmconf package. I removed this package, similarly if you get any conflicts just remove those packages and try running the above upgrade command.
Step 5: Install the New Kernel Core for CentOS 8
To install a new kernel for CentOS 8, run the command.
# dnf -y install kernel-core
Finally, install CentOS 8 minimal package.
# dnf -y groupupdate "Core" "Minimal Install"
Now you can check the version of CentOS installed by running.
# cat /etc/redhat-release
If you see the above output, I have successfully upgraded from CentOS 7 to CentOS 8.5 release.
Read Also: How to Set Up Automatic Updates for CentOS 8
Conclusion
This article concludes on how you can upgrade from CentOS 7 to CentOS 8. We hope you found this insightful.
[email protected] ~# dnf clean all
71 files removed
[email protected] ~# rpm -e `rpm -q kernel`
package `rpm is not installed
package kernel` is not installed
[email protected] ~# rpm -e –nodeps sysvinit-tools
[email protected] ~# dnf -y –releasever=8 –allowerasing –setopt=deltarpm=false distro-sync
Extra Packages for Enterprise Linux 8 – x86_64 16 MB/s | 11 MB 00:00
CentOS Linux 8 – BaseOS 6.0 MB/s | 4.6 MB 00:00
ELRepo.org Community Enterprise Linux Repository – el7 167 kB/s | 296 kB 00:01
Nux.Ro RPMs for general desktop use 2.6 MB/s | 4.2 MB 00:01
Extra Packages for Enterprise Linux Modular 8 – x86_64 1.3 MB/s | 979 kB 00:00
Copr repo for snapcore-el7 owned by ngompa 46 kB/s | 27 kB 00:00
CentOS Linux 8 – AppStream 1.9 MB/s | 8.4 MB 00:04
CentOS Linux 8 – Extras 238 kB/s | 10 kB 00:00
Error:
Problem: The operation would result in removing the following protected packages: kernel
How to fix it now?
THIS IS NOT A SUPPORTED METHOD TO UPGRADE !!
Do NOT follow this or any other ‘upgrade‘ steps you find, as it will most likely fail unless you’re on a brand new system with almost nothing installed/configured to it, and you’ll end up with a very crippled machine that may not survive a reboot again without a full re-install.
THIS IS NOT A SUPPORTED METHOD TO UPGRADE !!
@rhanthony,
I have tried the same method on my 3 old CentOS 7 machines and they have successfully upgraded to CentOS 8…
I failed below:
It complained python conflict:
...
file /usr/lib64/python3.6/xml/sax/__pycache__/xmlreader.cpython-36.pyc from install of python3-libs-3.6.8-18.el7.x86_64 conflicts with file from package python36u-libs-3.6.8-1.el7.ius.x86_64
How come first we remove the old kernel, and only then – install new? Can the system operate without a kernel? :O
The kernel used for the server while it is running (on power) is in the RAM already. So even if you delete the rpm package of the Linux kernel (or any other running application, e.g. the ftp package on a running ftp server ) the server still is running BUT now you could not reboot it, because, after the reboot, the Linux kernel would not be found anywhere to be loaded in the RAM.
So when the steps of the article are done, your server will still run with a kernel of centos7.9, and after a reboot, it will start with the kernel of 8.1, I hope I say it correctly. The article should have mentioned in the end to do a reboot.
Running transaction check
Error: transaction check vs depsolve:
(NetworkManager >= 1.20 or dhclient) is needed by dracut-network-049-191.git20210920.el8.x86_64
rpmlib(RichDependencies) <= 4.12.0-1 is needed by dracut-network-049-191.git20210920.el8.x86_64
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'.
@Fredo,
Remove the dracut-network package and try again.
@ravi this command doesn’t help. I have the same issue as @fredo
Firstly, yum has already been removed in one of the previous steps. Secondly, dracut-network is not installed and can’t be removed with either rpm or dnf.
@Fredo I fixed the issue by running
`rpm -Va --nofiles --nodigest`and removing all the packages with missing dependencies.In my case:
dnf -y groupupdate "Core" "Minimal Install"Last metadata expiration check: 0:09:42 ago on Tuesday 23 November 2021 11:09:26 AM IST.
No match for group package “rhc”
Error:
Problem 1: package dracut-049-191.git20210920.el8.x86_64 requires systemd >= 239-23, but none of the providers can be installed- package systemd-239-51.el8.i686 obsoletes systemd < 229-5 provided by systemd-219-78.el7_9.3.x86_64
- cannot install both systemd-239-51.el8.x86_64 and systemd-219-78.el7_9.3.x86_64
- package systemd-239-51.el8.x86_64 obsoletes systemd = 049-129, but none of the providers can be installed
- package systemd-sysv-219-78.el7_9.3.x86_64 requires systemd = 219-78.el7_9.3, but none of the providers can be installed
- conflicting requests
- problem with installed package systemd-sysv-219-78.el7_9.3.x86_64
Problem 2: package python3-hawkey-0.63.0-3.el8.x86_64 requires librpm.so.8()(64bit), but none of the providers can be installed
- package python3-hawkey-0.63.0-3.el8.x86_64 requires librpmio.so.8()(64bit), but none of the providers can be installed
- package python3-dnf-plugins-core-4.0.21-3.el8.noarch requires python3-hawkey >= 0.46.1, but none of the providers can be installed
- cannot install both rpm-libs-4.14.3-19.el8.x86_64 and rpm-libs-4.11.3-46.el7_9.x86_64
- package dnf-plugins-core-4.0.21-3.el8.noarch requires python3-dnf-plugins-core = 4.0.21-3.el8, but none of the providers can be installed
- package deltarpm-3.6-3.el7.x86_64 requires librpm.so.3()(64bit), but none of the providers can be installed
- package deltarpm-3.6-3.el7.x86_64 requires librpmio.so.3()(64bit), but none of the providers can be installed
- conflicting requests
- problem with installed package deltarpm-3.6-3.el7.x86_64
Problem 3: package python3-dnf-4.7.0-4.el8.noarch requires dnf-data = 4.7.0-4.el8, but none of the providers can be installed
- package dnf-4.7.0-4.el8.noarch requires python3-dnf = 4.7.0-4.el8, but none of the providers can be installed
- cannot install both dnf-data-4.7.0-4.el8.noarch and dnf-data-4.0.9.2-2.el7_9.noarch
- package yum-4.7.0-4.el8.noarch requires dnf = 4.7.0-4.el8, but none of the providers can be installed
- package python2-dnf-4.0.9.2-2.el7_9.noarch requires dnf-data = 4.0.9.2-2.el7_9, but none of the providers can be installed
- conflicting requests
- problem with installed package python2-dnf-4.0.9.2-2.el7_9.noarch
(try to add '--allowerasing' to command line to replace conflicting packages or '--skip-broken' to skip uninstallable packages)
@Sai,
Does the following command is successful? I suggest you re-run the following command and see if there are any package conflicts, if yes remove those conflicts and run the command again.
Hi! I see more than 170 comments about this article. Has the procedure been updated? I got stuck at distro-sync step D:
@Luca,
The article has been updated and included instructions for upgrading from CentOS 7.x to CentOS 8.5…
Will this cause the wiping of data on the server?
# dnf -y --releasever=8 --allowerasing --setopt=deltarpm=false distro-syncLast metadata expiration check: 0:34:40 ago on Sun 14 Nov 2021 12:48:00 PM IST.
Error:
Problem: The operation would result in removing the following protected packages: kernel-plus
Hi! How to solve the issue?
No, has not been updated. Use another source (Server Fault for example).
@Milan,
We are in the process to update this article, give us some time to research, test, and document it..
@Milan,
The article has been updated and included instructions for upgrading from older CentOS 7 to CentOS 8.5 release…
Can you please link it? I just set up my VM for testing. Thanks :)
@Luca,
The article has been just updated with new instructions for upgrading from older CentOS 7 to CentOS 8.5 release…
Do test it, it will work 100% without any errors…