How to Upgrade CentOS 7 to CentOS 8 Linux

James KiarieJuly 16, 2021November 11, 2019 CentOS 167 Comments

In this article, you will learn how to upgrade CentOS 7 to CentOS 8. 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 resolves 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 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-8-2.el8.noarch.rpm,centos-linux-release-8.4-1.2105.el8.noarch.rpm,centos-gpg-keys-8-2.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

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

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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167 thoughts on “How to Upgrade CentOS 7 to CentOS 8 Linux”

V

September 1, 2021 at 12:38 pm
On the last command, I added --skipbroken, because I could not resolve all dependencies.

My question is, when you reboot, which kernel is supposed to boot up the system? With the command uname -r I still get 3.10.0-1160.36.2.el7.x86_64, old version.

With:
```
# dnf list installed kernel
```
Installed Packages
kernel.x86_64 3.10.0-1160.36.2.el7 @System
kernel.x86_64 4.18.0-305.12.1.el8_4 @baseos
Reply
- Ravi Saive
  
  September 1, 2021 at 12:52 pm
  
  @Viselda,
  
  You need to define the Kernel version in your Grub configuration to boot the defined kernel…
  Reply
  - V
    
    September 1, 2021 at 12:55 pm
    
    Thanks for answering!
    
    What about the conflicts? How can I solve them because I cannot run update/upgrade commands?
    
    Here is part of what I get:
    
    file /usr/lib/python3.6/site-packages/setuptools/command/__pycache__/upload.cpython-36.opt-1.pyc from install of platform-python-setuptools-39.2.0-6.el8.noarch conflicts with file from package python3-setup tools-39.2.0-10.el7.noarch
    file /usr/lib/python3.6/site-packages/setuptools/command/__pycache__/upload.cpython-36.pyc from install of platform-python-setuptools-39.2.0-6.el8.noarch conflicts with file from package python3-setuptools- 39.2.0-10.el7.noarch
    file /usr/lib/python3.6/site-packages/setuptools/command/__pycache__/upload_docs.cpython-36.opt-1.pyc from install of platform-python-setuptools-39.2.0-6.el8.noarch conflicts with file from package python3- setuptools-39.2.0-10.el7.noarch
    file /usr/lib/python3.6/site-packages/setuptools/command/__pycache__/upload_docs.cpython-36.pyc from install of platform-python-setuptools-39.2.0-6.el8.noarch conflicts with file from package python3-setupt ools-39.2.0-10.el7.noarch
    file /usr/lib64/libgdbm_compat.so.4.0.0 from install of gdbm-libs-1:1.18-1.el8.x86_64 conflicts with file from package gdbm-1.10-8.el7.x86_64
    Reply
Don Levey

August 26, 2021 at 8:10 pm

UPDATE: I cannot recommend this upgrade method. I have made some progress, but am still in dependency hell. I have done 'yum --best --allowerasing -x upgrade a* b*' and so on, iterating through the alphabet and adding packages that break the process.

I still have a list I can’t upgrade, and still have a list that prevents distsync. I am concerned that any reboot will completely hose the system, especially as I run headless. I am on the verge of major surgery (removing mariadb, for example), but even then a dnf upgrade is required but I cannot do so because it is protected (and would require erasing). At this point, I need to sink $$$ into the project, build a completely new system, and migrate each package and config over piece by piece. Grr.
Reply
- Don Levey
  
  August 26, 2021 at 9:05 pm
  
  The current output of distsync:
  
  rror: transaction check vs depsolve:
  (gcc >= 8 with gcc < 9) is needed by annobin-9.50-1.el8.x86_64
  rpmlib(RichDependencies) = 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
  (ipa-selinux if selinux-policy-targeted) is needed by ipa-common-4.9.2-3.module_el8.4.0+780+c53619b9.noarch
  rpmlib(RichDependencies) <= 4.12.0-1 is needed by ipa-common-4.9.2-3.module_el8.4.0+780+c53619b9.noarch
  (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'.
  
  Trying to install via DNF gives error "none of the providers can be installed" e.g:
  – package ipa-common-4.9.2-3.module_el8.4.0+780+c53619b9.noarch requires (ipa-selinux if selinux-policy-targeted), but none of the providers can be installed
  Reply
V

August 23, 2021 at 12:50 pm
In the last step:
```
# dnf -y groupupdate "Core" "Minimal Install" 
```
I get the following error:

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) = 1.20 or dhclient) is needed by dracut-network-049-135.git20210121.el8.x86_64
rpmlib(RichDependencies) <= 4.12.0-1 is needed by dracut-network-049-135.git20210121.el8.x86_64

I also tried the following command, but that didn't work either. Help because I'm stuck here.
```
# dnf -y groupupdate "Core" "Minimal Install" --allowerasing
```
Reply
Don Levey

August 19, 2021 at 10:51 pm

When running the distrosync, I get the following error(s):

Running transaction check
Error: transaction check vs depsolve:
(gcc >= 8 with gcc < 9) is needed by annobin-9.50-1.el8.x86_64
rpmlib(RichDependencies) = 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) = 1.20 or dhclient) is needed by dracut-network-049-135.git20210121.el8.x86_64
rpmlib(RichDependencies) <= 4.12.0-1 is needed by dracut-network-049-135.git20210121.el8.x86_64
(flatpak-selinux = 1.8.5-3.el8 if selinux-policy-targeted) is needed by flatpak-1.8.5-3.el8.x86_64
rpmlib(RichDependencies) <= 4.12.0-1 is needed by flatpak-1.8.5-3.el8.x86_64
(ipa-selinux if selinux-policy-targeted) is needed by ipa-common-4.9.2-3.module_el8.4.0+780+c53619b9.noarch
rpmlib(RichDependencies) <= 4.12.0-1 is needed by ipa-common-4.9.2-3.module_el8.4.0+780+c53619b9.noarch
(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'.

For these "needed by ” is it safe to remove (and possibly reinstall) those to run the distrosync? Or have I screwed something up?
Reply
Brad Goodman

August 18, 2021 at 2:30 am

This is now giving me some unresolved packages and not letting me continue. But these steps also had me remove my kernel beforehand – so I appear to now be without a kernel, and unable to upgrade!? RPM commands now fail with some non-descript message about a repo (doesn’t tell me which one) being configured wrong. I think I’ve hosed my system…
Reply
Alex P

August 11, 2021 at 1:47 am
```
# rpm -e `rpm -q kernel`
```
should be
```
# rpm -e --nodeps kernel
```
Reply
Ahmed Kamal

August 3, 2021 at 9:16 pm

Thanks! This was really helpful, and also had a very annoying bug.

You only instruct to install `kernel-core`, while I think probably everyone will also need to install `kernel-modules`. I followed the instructions to upgrade my remote VPS, rebooted and there was no network!! Turns out the drivers are actually in the kernel-modules rpm. Ofc installing anything with a broken NIC driver is very painful. So, I pasting this to hopefully save someone else that pain.

Thanks!
Reply
Vincent_TX

July 15, 2021 at 9:57 pm

Thanks for the guide.

Step #4: the mirror URL should be:
dnf install http://mirror.centos.org/centos/8/BaseOS/x86_64/os/Packages/{centos-linux-repos-8-2.el8.noarch.rpm,centos-linux-release-8.4-1.2105.el8.noarch.rpm,centos-gpg-keys-8-2.el8.noarch.rpm}
Reply
- Ravi Saive
  
  July 16, 2021 at 11:29 am
  
  @Vincent,
  
  Thanks, updated the mirror link in the article…
  Reply
kiran Bhoir

July 9, 2021 at 9:56 pm

Can any guide if have a solution for this issue

Running scriptlet: libwbclient-4.13.3-3.el8.x86_64 1213/1213
Running scriptlet: kernel-core-4.18.0-305.7.1.el8_4.x86_64 1213/1213

Broadcast message from [email protected]local (Fri 2021-07-09 19:37:35 IST):

dracut[27540]: Can’t write to /boot/301e98982ddb4aa99dc45bc92cc698d3/4.18.0-305.7.1.el8_4.x86_64: Directory /boot/301e98982ddb4aa99dc45bc92cc698d3/4.18.0-305.7.1.el8_4.x86_64 does not exist or is not accessible.

Message from [email protected] at Jul 9 19:37:35 …
dracut:Can’t write to /boot/301e98982ddb4aa99dc45bc92cc698d3/4.18.0-305.7.1.el8_4.x86_64: Directory /boot/301e98982ddb4aa99dc45bc92cc698d3/4.18.0-305.7.1.el8_4.x86_64 does not exist or is not accessible.
Can’t write to /boot/301e98982ddb4aa99dc45bc92cc698d3/4.18.0-305.7.1.el8_4.x86_64: Directory /boot/301e98982ddb4aa99dc45bc92cc698d3/4.18.0-305.7.1.el8_4.x86_64 does not exist or is not accessible.
warning: %posttrans(kernel-core-4.18.0-305.7.1.el8_4.x86_64) scriptlet failed, exit status 1

Error in POSTTRANS scriptlet in rpm package kernel-core
Running scriptlet: authselect-libs-1.2.2-2.el8.x86_64 1213/1213
Running scriptlet: httpd-2.4.37-39.module_el8.4.0+778+c970deab.x86_64 1213/1213
Running scriptlet: authselect-compat-1.2.2-2.el8.x86_64 1213/1213
Running scriptlet: tuned-2.15.0-2.el8_4.1.noarch 1213/1213
Running scriptlet: microcode_ctl-4:20210216-1.20210525.1.el8_4.x86_64 1213/1213
/usr/lib/dracut/modules.d/40network/module-setup.sh: line 33: warning: command substitution: ignored null byte in input
/usr/lib/dracut/modules.d/40network/module-setup.sh: line 33: warning: command substitution: ignored null byte in input
/usr/lib/dracut/modules.d/40network/module-setup.sh: line 33: warning: command substitution: ignored null byte in input
/usr/lib/dracut/modules.d/40network/module-setup.sh: line 33: warning: command substitution: ignored null byte in input
Reply

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