How to Upgrade CentOS 7 to CentOS 8 Linux

James KiarieLast Updated: February 7, 2022 Read Time: 2 minsCentOS 244 Comments

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://vault.centos.org/8.5.2111/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}

Note: CentOS 8 is dead and all the repos have been moved to vault.centos.org.

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.

Conclusion

This article concludes on how you can upgrade from CentOS 7 to CentOS 8. We hope you found this insightful.

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244 Comments

Leave a Reply

A

December 7, 2024 at 11:05 pm
Actually, if you try this upgrade from CentOS 7.9, it will not work as it will break the upgrade due to:
```
Running transaction check  
Error: transaction check vs depsolve:  
(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  

To diagnose the problem, try running: 'rpm -Va --nofiles --nodigest'.  
You probably have a corrupted RPMDB, and 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'.  
```
I lost 2 hours and couldn’t find a way to install the desired MariaDB version as there’s a loop break with the desired mariadb-connector-c-3.1.11-2.el8_3.x86_64, and it simply does not work.
Reply
- Ravi Saive
  
  December 16, 2024 at 11:46 am
  
  @A,
  
  That sounds frustrating! It seems like a dependency issue with the MariaDB version and the connector. Have you tried rebuilding the RPM database using 'rpm --rebuilddb' or checking if there’s a specific version of MariaDB that matches the required dependencies? Sometimes clearing the cache with 'dnf clean packages' can help too.
  
  Let me know if you need any further assistance!
  Reply

Hi,

I got this issue when trying to sync the package with Centos 8.

# dnf --releasever=8 --setopt=deltarpm=false --setopt=protected_packages=  distro-sync -y

CentOS Linux 8 - BaseOS
CentOS Linux 8 - AppStream
Failed to synchronize cache for repo 'baseos', ignoring this repo.
Failed to synchronize cache for repo 'appstream', ignoring this repo.
Last metadata expiration check: 1:02:50 ago on Mon 04 Mar 2024 12:31:47 AM EST.
Error: 
 Problem: problem with installed package libssh2-1.8.0-4.el7_9.1.aarch64
  - libssh2-1.8.0-4.el7_9.1.aarch64 does not belong to a distupgrade repository
  - nothing provides libcrypto.so.1.1()(64bit) needed by libssh2-1.10.0-1.el8.aarch64
  - nothing provides libcrypto.so.1.1(OPENSSL_1_1_0)(64bit) needed by libssh2-1.10.0-1.el8.aarch64
  - nothing provides libssl.so.1.1()(64bit) needed by libssh2-1.10.0-1.el8.aarch64
  - nothing provides libcrypto.so.1.1(OPENSSL_1_1_1)(64bit) needed by libssh2-1.10.0-1.el8.aarch64

# dnf distro-sync

CentOS Linux 8 - BaseOS            
CentOS Linux 8 - AppStream         
Failed to synchronize cache for repo 'baseos', ignoring this repo.
Failed to synchronize cache for repo 'appstream', ignoring this repo.
Last metadata expiration check: 1:06:38 ago on Mon 04 Mar 2024 12:31:47 AM EST.
Error: 
 Problem: problem with installed package libssh2-1.8.0-4.el7_9.1.aarch64
  - libssh2-1.8.0-4.el7_9.1.aarch64 does not belong to a distupgrade repository
  - nothing provides libcrypto.so.1.1()(64bit) needed by libssh2-1.10.0-1.el8.aarch64
  - nothing provides libcrypto.so.1.1(OPENSSL_1_1_0)(64bit) needed by libssh2-1.10.0-1.el8.aarch64
  - nothing provides libssl.so.1.1()(64bit) needed by libssh2-1.10.0-1.el8.aarch64
  - nothing provides libcrypto.so.1.1(OPENSSL_1_1_1)(64bit) needed by libssh2-1.10.0-1.el8.aarch64

And when I tried to remove the package libssh2, this is what I got:

# dnf remove libssh2

Error: 
 Problem: The operation would result in removing the following protected packages: systemd

Is there any ideas to fix this?

Ravi Saive

March 4, 2024 at 2:50 pm
@Thuy,

You have libssh2-1.8.0-4.el7_9.1.aarch64 installed, which belongs to CentOS Linux 7 repository, which isn’t compatible with your CentOS 8 system.

Updating it to the latest libssh2 version might fix the issue.
```
sudo sudo dnf update
sudo dnf update libssh2
```
Reply

Hal Bouma

November 25, 2023 at 2:30 am
Hi,

Thanks for the guide. I’ve been doing distro upgrades since Redhat 7.3 to RedHat 9/RHEL 3 almost twenty years ago so I’m pretty well versed in these. However, I’ve ran into an issue after doing my first upgrade. dnf/yum runs out of memory when trying to do the epel repo (see below).

This happens even if I raise the memory limit to 8GB of RAM and almost all of it is free.

Do you know what is tripping this up? I’m sure its some limit setting somewhere.
```
# dnf update

AlmaLinux 8 - BaseOS                                                                                                         10 MB/s | 2.9 MB     00:00
AlmaLinux 8 - AppStream                                                                                                      24 MB/s | 9.8 MB     00:00
Out of memory allocating 16777216 bytes!
Aborted (core dumped)
```
Reply
- Ravi Saive
  
  November 28, 2023 at 9:03 am
  
  @Hal,
  
  To view the minimum and recommended requirements, as well as the maximum limits supported by the releases, please refer to: https://access.redhat.com/articles/rhel-limits
  Reply
graziano

November 3, 2023 at 1:43 pm

I have CentOS 7.9 and your guide for me fails at this point.

[root@CentOS-73-64-minimal ~]# yum install -y leapp-upgrade leapp-data-almalinux

–> Finished Dependency Resolution
Error: Package: 1:leapp-upgrade-el7toel8-0.16.0-6.el7.elevate.17.noarch (elevate)
Requires: python2-leapp
Error: Package: 1:leapp-upgrade-el7toel8-deps-0.16.0-6.el7.elevate.17.noarch (elevate)
Requires: python-requests
Error: Package: 1:leapp-upgrade-el7toel8-deps-0.16.0-6.el7.elevate.17.noarch (elevate)
Requires: dnf >= 4
Error: Package: leapp-0.14.0-1.el7.noarch (elevate)
Requires: python2-leapp = 0.14.0-1.el7
Error: Package: 1:leapp-upgrade-el7toel8-0.16.0-6.el7.elevate.17.noarch (elevate)
Requires: leapp-framework >= 2.2
You could try using –skip-broken to work around the problem
You could try running: rpm -Va –nofiles –nodigest

Any idea to solve this ?
Reply
- Ravi Saive
  
  November 4, 2023 at 9:24 am
  @Graziano,
  
  The error message you’re encountering indicates that there are several unmet dependencies when trying to install the leapp-upgrade and leapp-data-almalinux packages.
  
  To fix this issue, you can follow below steps:
  
  1. Ensure your system is up to date:
```
sudo yum update
```
  2. To satisfy the dependencies, you can try installing the required packages one by one:
```
sudo yum install python2-leapp
sudo yum install python-requests
```
  3. For the dnf >= 4 requirement, you may need to update or install DNF:
```
sudo yum install dnf
```
  4. You can try installing leapp-framework with the specified version:
```
sudo yum install leapp-framework-2.2
```
  5. After resolving these dependencies, try installing leapp-upgrade and leapp-data-almalinux again:
```
sudo yum install -y leapp-upgrade leapp-data-almalinux
```
  If you encounter any additional dependency issues during this process, make sure to address them as well. If there are conflicts or issues that cannot be resolved, you may need to contact the package maintainers or the repository maintainers for assistance, as they might need to update their packages to resolve the dependencies.
  Reply
Pablo Olivarez

July 18, 2023 at 8:45 pm
Hello, I’m stuck in a several problems. Yum didn’t work. Dnf is not installed. All this problems happen before this step
```
# dnf install http://vault.centos.org/8.5.2111/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}
```
There was a problem importing one of the Python modules required to run yum.

The error leading to this problem was:
```
/usr/lib64/python2.7/site-packages/pycurl.so: undefined symbol: CRYPTO_num_locks
```
Please install a package which provides this module, or verify that the module is installed correctly.

It’s possible that the above module doesn’t match the current version of Python, which is:
```
2.7.5 (default, Jun 20 2023, 11:36:40) 
[GCC 4.8.5 20150623 (Red Hat 4.8.5-44)]
```
If you cannot solve this problem yourself, please go to the yum faq at: http://yum.baseurl.org/wiki/Faq

Maybe is time to say goodbye to centos………
Reply
- Ravi Saive
  
  July 19, 2023 at 9:35 am
  @Pablo,
  
  The error message you mentioned indicates that there is an issue with the pycurl module in your Python installation, which appears that there is a missing or incompatible symbol related to OpenSSL’s CRYPTO_num_locks function.
  
  Try reinstalling the pycurl (python-pycurl) module to ensure that you have the latest version that is compatible with your updated OpenSSL.
```
# yum install python-pycurl
OR
# dnf install python-pycurl
```
  Reply
Martin

April 19, 2023 at 1:48 pm
For me, it ends like in the above comment:
```
# dnf --releasever=8 --allowerasing --setopt=deltarpm=false distro-sync
CentOS Linux 8 - BaseOS                                                                                      
CentOS Linux 8 - AppStream    
Failed to synchronize cache for repo 'baseos', ignoring this repo.
Failed to synchronize cache for repo 'appstream', ignoring this repo.
Last metadata expiration check: 0:01:07 ago on 2023-01-15T13:39:04 UTC.
Error: 
 Problem: The operation would result in removing the following protected packages: dnf
```
Reply
- Ignacio
  
  December 12, 2023 at 8:14 pm
  
  I am also facing the same error while trying to upgrade CentOS 7 to CentOS 8.
  Reply
- Ravi Saive
  
  December 13, 2023 at 8:41 am
  @Martin,
  
  It seems like you’re encountering an issue with the DNF package manager on CentOS 8, to fix this issue you can try the following steps:
  
  1. Update the DNF package to the latest version available in the repository.
```
sudo dnf update dnf
```
  2. After updating DNF, try running the system update again.
```
sudo dnf --releasever=8 --allowerasing --setopt=deltarpm=false distro-sync
```
  If the issue persists, you may try reinstalling the ‘dnf’ package:
```
sudo dnf reinstall dnf
```
  If the problem is related to dependencies, you may need to address those dependencies before attempting the update.
  Reply

I am stuck in this:

(700/701): ntfs-3g-2022.10.3-1.el8.x86_64.rpm                    459 kB/s | 133 kB     00:00
(701/701): ntfsprogs-2022.10.3-1.el8.x86_64.rpm                  1.2 MB/s | 404 kB     00:00
-----------------------------------------------------------------------------------------------
Total                                                            649 kB/s | 724 kB     00:01
Running transaction check
Error: transaction check vs depsolve:
(gcc >= 8 with gcc < 9) is needed by annobin-9.72-1.el8_5.2.x86_64
rpmlib(RichDependencies) <= 4.12.0-1 is needed by annobin-9.72-1.el8_5.2.x86_64
(annobin if gcc) is needed by redhat-rpm-config-125-1.el8.noarch
rpmlib(RichDependencies) <= 4.12.0-1 is needed by redhat-rpm-config-125-1.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'.

Sunil

February 2, 2023 at 10:18 pm

Hi Ravi, I am having issues when I try to – Next, install CentOS 8 release package using dnf as shown below. This will take a while.

# dnf install http://vault.centos.org/8.5.2111/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} CentOS-7 - Base 0.0 B/s | 0 B 00:00 CentOS-7 - Updates 0.0 B/s | 0 B 00:00 CentOS-7 - Extras 0.0 B/s | 0 B 00:00 Failed to synchronize cache for repo 'base', ignoring this repo. Failed to synchronize cache for repo 'updates', ignoring this repo. Failed to synchronize cache for repo 'extras', ignoring this repo. Last metadata expiration check: 0:01:24 ago on Thu 02 Feb 2023 04:42:15 PM UTC. [MIRROR] centos-linux-repos-8-3.el8.noarch.rpm: Curl error (56): Failure when receiving data from the peer for http://vault.centos.org/8.5.2111/BaseOS/x86_64/os/Packages/centos-linux-repos-8-3.el8.noarch.rpm [Recv failure: Connection reset by peer] [FAILED] centos-linux-repos-8-3.el8.noarch.rpm: Curl error (56): Failure when receiving data from the peer for http://vault.centos.org/8.5.2111/BaseOS/x86_64/os/Packages/centos-linux-repos-8-3.el8.noarch.rpm [Recv failure: Connection reset by peer] Curl error (56): Failure when receiving data from the peer for http://vault.centos.org/8.5.2111/BaseOS/x86_64/os/Packages/centos-linux-repos-8-3.el8.noarch.rpm [Recv failure: Connection reset by peer]
Any suggestions/thoughts?

Thanks
Sunil
Reply
- Ravi Saive
  
  February 3, 2023 at 11:46 am
  
  @Sunil,
  
  Check your system timezone, date, and time, and set the time and date to the current date…
  Reply
  - Sunil
    
    February 6, 2023 at 10:30 pm
    Thanks, Ravi!
    
    Changed the time and time zone. Now I am unable to remove the old kernel and also unable to upgrade the kernel version.
    
    $ rpm -e `rpm -q kernel` error: Failed dependencies: kernel >= 2.6.32 is needed by (installed) lldpad-1.0.1-7.git036e314.el7_9.x86_64 kernel >= 2.6.32 is needed by (installed) lldpad-1.0.1-7.git036e314.el7_9.x86_64
    
    [root]# dnf -y install kernel-core CentOS-7 - Base CentOS-7 - Updates CentOS-7 - Extras Failed to synchronize cache for repo 'base', ignoring this repo. Failed to synchronize cache for repo 'updates', ignoring this repo. Failed to synchronize cache for repo 'extras', ignoring this repo. Last metadata expiration check: 0:01:55 ago on Mon 06 Feb 2023 11:54:47 AM EST. No match for argument: kernel-core Error: Unable to find a match: kernel-core
    
    Any help here
    Thanks
    Sunil
    Reply
    - Ravi Saive
      
      February 7, 2023 at 12:47 pm
      
      @Sunil,
      
      There could be three reasons for getting a such error:
      
      1. Incorrect date and time settings
      2. Old dnf cache expired
      3. CentOS baseURL
      
      Fix these issues by:
      
      # timedatectl set-timezone "Asia/Kolkata" # dnf install http://vault.centos.org/8.5.2111/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} # dnf -y upgrade https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm # dnf clean all # rpm -e `rpm -q kernel`
      Reply
      - Sunil
        
        February 7, 2023 at 8:39 pm
        
        Hi Ravi, The server is in USA EST, so I set it to EST time.
        
        Still getting the same error –
        
        [root@~]# date Tue Feb 7 10:06:07 EST 2023
        
        [root@c~]# dnf install http://vault.centos.org/8.5.2111/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} CentOS-7 - Base 0.0 B/s | 0 B 00:00 CentOS-7 - Updates 0.0 B/s | 0 B 00:00 CentOS-7 - Extras 0.0 B/s | 0 B 00:00 Failed to synchronize cache for repo 'base', ignoring this repo. Failed to synchronize cache for repo 'updates', ignoring this repo. Failed to synchronize cache for repo 'extras', ignoring this repo. Last metadata expiration check: 22:11:40 ago on Mon 06 Feb 2023 11:54:47 AM EST. [MIRROR] centos-linux-repos-8-3.el8.noarch.rpm: Curl error (56): Failure when receiving data from the peer for http://vault.centos.org/8.5.2111/BaseOS/x86_64/os/Packages/centos-linux-repos-8-3.el8.noarch.rpm [Recv failure: Connection reset by peer] [FAILED] centos-linux-repos-8-3.el8.noarch.rpm: Curl error (56): Failure when receiving data from the peer for http://vault.centos.org/8.5.2111/BaseOS/x86_64/os/Packages/centos-linux-repos-8-3.el8.noarch.rpm [Recv failure: Connection reset by peer] Curl error (56): Failure when receiving data from the peer for http://vault.centos.org/8.5.2111/BaseOS/x86_64/os/Packages/centos-linux-repos-8-3.el8.noarch.rpm [Recv failure: Connection reset by peer]
      - Ravi Saive
        
        February 8, 2023 at 11:26 am
        
        @Sunil,
        
        It seems your curl doesn’t support SSL/TLS properly. Try to update or upgrade your system with:
        
        $ dnf update $ dnf upgrade
      - Sunil
        
        February 8, 2023 at 6:48 pm
        
        Hi Ravi, Still no luck
        
        [root@INDPCS ~]# dnf update CentOS-7 - Base 0.0 B/s | 0 B 00:00 CentOS-7 - Updates 0.0 B/s | 0 B 00:00 CentOS-7 - Extras 0.0 B/s | 0 B 00:00 Failed to synchronize cache for repo 'base', ignoring this repo. Failed to synchronize cache for repo 'updates', ignoring this repo. Failed to synchronize cache for repo 'extras', ignoring this repo. Last metadata expiration check: 16:13:48 ago on Tue 07 Feb 2023 04:02:13 PM EST. Dependencies resolved. Nothing to do. Complete!
        
        [root@INDPCS ~]# dnf upgrade CentOS-7 - Base 0.0 B/s | 0 B 00:00 CentOS-7 - Updates 0.0 B/s | 0 B 00:00 CentOS-7 - Extras 0.0 B/s | 0 B 00:00 Failed to synchronize cache for repo 'base', ignoring this repo. Failed to synchronize cache for repo 'updates', ignoring this repo. Failed to synchronize cache for repo 'extras', ignoring this repo. Last metadata expiration check: 16:14:10 ago on Tue 07 Feb 2023 04:02:13 PM EST. Dependencies resolved. Nothing to do.
        
        Complete!
        [root@INDPCS ~]#
      - Ravi Saive
        
        February 10, 2023 at 12:23 pm
        
        @Sunil,
        
        It looks like your repos are empty, I suggest you check the repos in /etc/yum.repos.d/ directory and see the sizes of the base, updates, and extras repository. Also, I suggest your to try to follow the instructions again from the beginning…
Donavan

January 29, 2023 at 5:09 am

Humm…

Be careful, some basic packages will be deleted with those steps of SSH service…

Regards
Reply
dargaud

January 15, 2023 at 7:19 pm
Hello,

Thanks for the instructions. It did seem easy enough to follow and worked well until:
```
# dnf --releasever=8 --allowerasing --setopt=deltarpm=false distro-sync
CentOS Linux 8 - BaseOS                                                                                      
CentOS Linux 8 - AppStream    
Failed to synchronize cache for repo 'baseos', ignoring this repo.
Failed to synchronize cache for repo 'appstream', ignoring this repo.
Last metadata expiration check: 0:01:07 ago on 2023-01-15T13:39:04 UTC.
Error: 
 Problem: The operation would result in removing the following protected packages: dnf
```
Google then took me to either irrelevant or highly complex and problematic pages… I’m going to revert my snapshot for maybe another try later.
Reply
- jd
  
  March 9, 2023 at 7:43 pm
  
  Uninstall dnf from the centos7 install before starting. Centos7 dnf uses python2, when following the process above the installation of dnf in order should pull a python3 version for you.
  Reply
- Leonard
  
  April 13, 2023 at 5:05 pm
  I had the same issue and kept trying different things.
  
  The solution I found was to search for the newest repositories from the CentOS 8 Stream and use this when installing the CentOS 8 repos:
```
# dnf install http://http://mirror.centos.org/centos/8-stream/BaseOS/x86_64/os/Packages/{centos-stream-repos-8-6.el8.noarch.rpm,centos-stream-release-8.6-1.el8.noarch.rpm,centos-gpg-keys-8-6.el8.noarch.rpm}
```
  After removing the old kernel I needed to remove the old python-pip package since this will conflict with other packages moving forward.
  
  Then I manually installed “NetworkManager” before executing:
```
#dnf -y --releasever=8 --allowerasing --setopt=deltarpm=false distro-sync
```
  Hopefully, this helps.
  Reply
Cyrus

January 4, 2023 at 3:15 pm
Hi,

I followed the procedure but at this stage:
```
# dnf -y install kernel-core
```
I’m getting the error:
```
No match for argument: kernel-core
Error: Unable to find a match: kernel-core.
```
My kernel version after running command uname -r:
```
3.10.0-957.el7.x86_64
```
Any idea appreciated.
Reply
- Ravi Saive
  
  January 5, 2023 at 10:25 am
  
  @Cyrus,
  
  To fix this problem you need to boot into rescue mode, then remove the existing linux-firmware package and then manually download and install kernel, kernel-core, and kernel-modules, linux-firmware using rpm -ivh kernel* command.
  
  After that reboot the machine…
  Reply
John

January 2, 2023 at 10:21 am
@Ravi Saive,

Works with that long sequence. I am somehow able to rpm -ivh kernel-modules after removing a lot of packages related to python3 maybe. Able to show and boot into Centos 8. But since I was deep with a lot of packages in CentOs 7, after doing a lot of dnf removal.

I ended up missing some crucial utilities after booting into CentOS 8. Ended up just reinstalling a CentOS 8. Was never able to run:
```
# dnf -y --releasever=8 --allowerasing --setopt=deltarpm=false distro-sync
```
Reply
- Ravi Saive
  
  January 2, 2023 at 12:59 pm
  
  @John,
  
  Sorry for the trouble, but I think you can install those missing utilities with dnf tool after booting into CentOS 8…
  Reply
Kvark

December 27, 2022 at 2:05 am

Before yum install rpmconf do yum update, that will allow you to fix the issue with the error: import error: no module named _conf on step 3 ending.
Reply
BOUNGOU STEPHANE

August 29, 2022 at 7:26 am

Good evening how to create a virtual workstation with Ulteo under Centos 8?
Reply
Richard Lawson

August 4, 2022 at 1:41 am

Just FYI, I followed this blueprint to do an in-place upgrade from CentOS 8-Stream to 9-Stream. The biggest difference is that the CentOS 9-Stream mirrors are in a different place (you can find them on Mirror Manager). Otherwise, the above process worked pretty well and I had surprisingly few issues getting CentOS 9 up and running.
Reply
- Kvark
  
  December 27, 2022 at 11:15 pm
  
  Could you please show what links and how you did it?
  Reply
chil

April 19, 2022 at 8:05 pm

The command # dnf -y --releasever=8 --allowerasing --setopt=deltarpm=false distro-sync fails. It will try to remove the protected dnf package.

Adding --setopt=protected_packages= is a really bad idea, because dnf is removed by itself.

Then you have a system without dnf, yum, or rpm. Not recommended!
Reply

How to upgrade CentOS 7.9 to CentOS 8.5

Type all the commands as root.

# yum install epel-release -y
# yum install yum-utils
# yum install rpmconf
# rpmconf -a

Answer the questions using the default. Usuallly it is N, in httpd case it is Y.

# package-cleanup --leaves
# package-cleanup --orphans
# yum install dnf
# dnf -y remove yum yum-metadata-parser
# rm -Rf /etc/yum
# dnf upgrade
# dnf install http://vault.centos.org/8.5.2111/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}
# dnf -y upgrade https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm --best --allowerasing
# dnf clean all
# rpm -e `rpm -q kernel`
# rpm -e --nodeps sysvinit-tools
# dnf remove kexec-tools
# dnf remove ivtv-firmware
# dnf remove linux-firmware
# cd /root
# wget http://mirror.centos.org/centos/8-stream/BaseOS/x86_64/os/Packages/linux-firmware-20210702-103.gitd79c2677.el8.noarch.rpm
# wget https://vault.centos.org/centos/8/BaseOS/x86_64/os/Packages/kernel-4.18.0-348.el8.x86_64.rpm
# wget https://vault.centos.org/centos/8/BaseOS/x86_64/os/Packages/kernel-modules-4.18.0-348.el8.x86_64.rpm
# wget https://vault.centos.org/centos/8/BaseOS/x86_64/os/Packages/kernel-core-4.18.0-348.el8.x86_64.rpm
# rpm -iv linux-firmware-20210702-103.gitd79c2677.el8.noarch.rpm
# rpm -iv kernel-modules-4.18.0-348.el8.x86_64.rpm
# cp /lib/modules/4.18.0-348.el8.x86_64/symvers.gz /boot/
# cd /boot 
# mv symvers.gz symvers-4.18.0-348.el8.x86_64.gz
# cd /root
# rpm -iv --replacepkgs kernel-core-4.18.0-348.el8.x86_64.rpm
# rpm -iv kernel-4.18.0-348.el8.x86_64.rpm
# cat /etc/redhat-release
# reboot

Check during the boot process is everything ok. Should be OK.

# dnf check-update
# dnf update nameofthepackage --best --allowerasing

———————– this is not fixed by me yet ———————————————
libssh2.x86_64 – this is not possible to be upgraded just because the problem is that it will not let the dnf package be removed

Dependencies described here:
http://rpm.pbone.net/info_idpl_75792859_distro_redhatel8_com_libssh2-1.9.0-5.el8.x86_64.rpm.html

Seems this is a huge dependencies issue, just because all those four libraries are not enough

# wget https://download-ib01.fedoraproject.org/pub/epel/8/Everything/x86_64/Packages/l/libssh2-1.9.0-5.el8.x86_64.rpm
# rpm -Uivh libssh2-1.9.0-5.el8.x86_64.rpm
error: Failed dependencies:
        libcrypto.so.1.1()(64bit) is needed by libssh2-1.9.0-5.el8.x86_64
        libcrypto.so.1.1(OPENSSL_1_1_0)(64bit) is needed by libssh2-1.9.0-5.el8.x86_64
        libcrypto.so.1.1(OPENSSL_1_1_1)(64bit) is needed by libssh2-1.9.0-5.el8.x86_64
        libssl.so.1.1()(64bit) is needed by libssh2-1.9.0-5.el8.x86_64

If you will try to download this one for CentOS 8 that contains all four libraries.

# wget https://vault.centos.org/8.1.1911/BaseOS/x86_64/os/Packages/openssl-libs-1.1.1c-2.el8_1.1.x86_64.rpm

And then if you will try to install it with this command:

# rpm -iv openssl-libs-1.1.1c-2.el8_1.1.x86_64.rpm

It will show these dependencies for example below. So a big surprise.

crypto-policies >= 20180730 is needed by openssl-libs-1:1.1.1c-2.el8_1.1.x86_64

# wget https://vault.centos.org/8.5.2111/BaseOS/x86_64/kickstart/Packages/krb5-libs-1.18.2-14.el8.x86_64.rpm
# rpm -iv krb5-libs-1.18.2-14.el8.x86_64.rpm

warning: krb5-libs-1.18.2-14.el8.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID 8483c65d: NOKEY
error: Failed dependencies:
        /etc/crypto-policies/back-ends/krb5.config is needed by krb5-libs-1.18.2-14.el8.x86_64
        libc.so.6(GLIBC_2.25)(64bit) is needed by krb5-libs-1.18.2-14.el8.x86_64
        libc.so.6(GLIBC_2.27)(64bit) is needed by krb5-libs-1.18.2-14.el8.x86_64
        libcrypto.so.1.1()(64bit) is needed by krb5-libs-1.18.2-14.el8.x86_64
        libcrypto.so.1.1(OPENSSL_1_1_0)(64bit) is needed by krb5-libs-1.18.2-14.el8.x86_64
        libcrypto.so.1.1(OPENSSL_1_1_1b)(64bit) is needed by krb5-libs-1.18.2-14.el8.x86_64
        libssl.so.1.1()(64bit) is needed by krb5-libs-1.18.2-14.el8.x86_64
        libssl.so.1.1(OPENSSL_1_1_0)(64bit) is needed by krb5-libs-1.18.2-14.el8.x86_64
        openssl-libs >= 1:1.1.1c-4 is needed by krb5-libs-1.18.2-14.el8.x86_64

Maybe it is possible to solve it by you know, checking which library has to be downloaded first and then downloading and installing them one by one in the correct order. Some day maybe will find out is it possible, but I am not sure.

Thereafter, launch the CentOS 8 system upgrade as shown.

# dnf -y --releasever=8 --allowerasing --setopt=deltarpm=false distro-sync

This will fail. So, instead of the above do the below without reboot:

# dnf remove kexec-tools
# dnf remove ivtv-firmware
# dnf remove linux-firmware
# cd /root
# wget http://mirror.centos.org/centos/8-stream/BaseOS/x86_64/os/Packages/linux-firmware-20210702-103.gitd79c2677.el8.noarch.rpm
# wget https://vault.centos.org/centos/8/BaseOS/x86_64/os/Packages/kernel-4.18.0-348.el8.x86_64.rpm
# wget https://vault.centos.org/centos/8/BaseOS/x86_64/os/Packages/kernel-modules-4.18.0-348.el8.x86_64.rpm
# wget https://vault.centos.org/centos/8/BaseOS/x86_64/os/Packages/kernel-core-4.18.0-348.el8.x86_64.rpm
# rpm -iv linux-firmware-20210702-103.gitd79c2677.el8.noarch.rpm
# rpm -iv kernel-modules-4.18.0-348.el8.x86_64.rpm
# cp /lib/modules/4.18.0-348.el8.x86_64/symvers.gz /boot/
# cd /boot 
# mv symvers.gz symvers-4.18.0-348.el8.x86_64.gz
# cd /root
# rpm -iv --replacepkgs kernel-core-4.18.0-348.el8.x86_64.rpm
# rpm -iv kernel-4.18.0-348.el8.x86_64.rpm
# cat /etc/redhat-release
# reboot

Check during the boot process is everything ok. Should be.

Adrian

February 22, 2022 at 3:27 pm

Replace:
# dnf -y --releasever=8 --allowerasing --setopt=deltarpm=false distro-sync
with:
# dnf --releasever=8 --setopt=deltarpm=false --setopt=protected_packages= --allowerasing distro-sync -y
Reply
- chil
  
  April 19, 2022 at 8:01 pm
  
  Tried that, but it removed dnf. Now the system is unusable.
  Reply
Eduardo Del Puerto

February 19, 2022 at 4:40 am

Running operation verification
Error: operation verification vs depsolve:
(NetworkManager >= 1.20 or dhclient) is needed by dracut-network-049-201.git20220131.el8.x86_64
rpmlib(RichDependencies) <= 4.12.0-1 is needed by dracut-network-049-201.git20220131.el8.x86_64
To detect the problem, try running: 'rpm -Va –nofiles –nodigest'.
You probably have a corrupted RPMDB, running 'rpm –rebuilddb' might fix the problem.
The downloaded packages have been cached for the next transaction.
You can clear packages from cache by removing 'dnf clean packages'.
Reply

Did not work for me.

# cat /etc/redhat-release

CentOS Linux release 7.9.2009 (Core)

Catalin Frent

February 9, 2022 at 4:35 am

Unfortunately, the vault.centos.org repo for CentOS 8 is out, too.

I just skipped CentOS entirely and From CentOS 7 I upgraded directly to CentOS 8 Stream using

dnf install --allowerasing http://mirrors.advancedhosters.com/centos/8-stream/BaseOS/x86_64/os/Packages/{centos-stream-repos-8-3.el8.noarch.rpm,centos-stream-release-8.6-1.el8.noarch.rpm,centos-gpg-keys-8-3.el8.noarch.rpm}

along with a few adjustments.
Reply
- Ravi Saive
  
  February 9, 2022 at 11:27 am
  
  @Catalin,
  
  I have updated the article and included the vault.centos.org repository…
  Reply
  - Andy
    
    February 9, 2022 at 6:03 pm
    Confirm it works with vault repos or with stream repos.
    
    Did upgrade with both repos.
    
    In some cases you can’t remove kernels from working OS, so you should boot into recovery mode and do it manually.
    
    1. Download kernel, kernel-core and kernel-modules, linux-firmware.
    
    wget https://vault.centos.org/centos/8/BaseOS/x86_64/os/Packages/kernel-4.18.0-348.el8.x86_64.rpm wget https://vault.centos.org/centos/8/BaseOS/x86_64/os/Packages/kernel-modules-4.18.0-348.el8.x86_64.rpm wget https://vault.centos.org/centos/8/BaseOS/x86_64/os/Packages/kernel-core-4.18.0-348.el8.x86_64.rpm
    
    2. Boot in rescue mode and remove existing linux-firmware package and install downloaded package.
    
    dnf remove kexec-tools dnf remove ivtv-firmware dnf remove linux-firmware
    
    3. Then Install kernel packages by (rpm -iv kernel*).
    
    rpm -iv linux-firmware-20210702-103.gitd79c2677.el8.noarch.rpm rpm -iv kernel-modules-4.18.0-348.el8.x86_64.rpm /boot/symvers -> symlink /lib/moules/4.18…/symvers.gz rpm -iv --replacepkgs kernel-core-4.18.0-348.el8.x86_64.rpm rpm -e --nodeps sysvinit-tools rpm -q kernel-3.10.... (your kernels here) and soft that depends on it
    
    5. Reboot.
    Reply
    - Walter
      
      February 17, 2022 at 1:55 am
      
      # rpm -iv linux-firmware-20210702-103.gitd79c2677.el8.noarch.rpm
      error: open of linux-firmware-20210702-103.gitd79c2677.el8.noarch.rpm failed: No such file or directory
      
      # rpm -iv kernel-modules-4.18.0-348.el8.x86_64.rpm
      error: Failed dependencies:
      kernel-uname-r = 4.18.0-348.el8.x86_64 is needed by kernel-modules-4.18.0-348.el8.x86_64
      
      # /boot/symvers -> symlink /lib/moules/4.18…/symvers.gz
      bash: /boot/symvers: No such file or directory
      Reply
      - Andy
        
        February 21, 2022 at 3:10 pm
        
        -> error: open of linux-firmware-20210702-103.gitd79c2677.el8.noarch.rpm failed: No such file or directory – ! You don’t have it.
        
        You should download it first.
        
        And symlink here is just an example – you should write the full kernel name you have. Like:
        /boot/symvers -> symlink /lib/moules/4.18.0-348.el8.x86_64/symvers.gz
      - John
        
        December 25, 2022 at 7:19 am
        
        I’m getting the same error when running:
        
        # rpm -iv kernel-modules-4.18.0-348.el8.x86_64.rpm
        
        error: Failed dependencies:
        kernel-uname-r = 4.18.0-348.el8.x86_64 is needed by kernel-modules-4.18.0-348.el8.x86_64
        
        When I ran the:
        
        # dnf -y --releasever=8 --allowerasing --setopt=deltarpm=false distro-sync
        
        I got an error I noticed some other people got:
        
        “Error:
        Problem: The operation would result in removing the following protected packages: kernel”
        
        How to get past the kernel-uname-r dependency error..?
      - Ravi Saive
        
        December 26, 2022 at 10:00 am
        
        @John,
        
        Check these comments, hope it will solve your problem:
        
        https://www.tecmint.com/upgrade-centos-7-to-centos-8/comment-page-11/#comment-1726257
        https://www.tecmint.com/upgrade-centos-7-to-centos-8/comment-page-11/#comment-1726239
- Walter
  
  February 17, 2022 at 1:03 am
  Seemed to work.
```
# cat /etc/redhat-release

CentOS Stream release 8
```
  Reply