How to Upgrade CentOS 7 to CentOS 8

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
Install EPEL Repo in CentOS 7
Install EPEL Repo in CentOS 7

Step 2: Install yum-utils Tools

After successfully installing EPEL, install yum-utils by running the command below.

# yum install yum-utils
Install yum-utils in CentOS 7
Install yum-utils in CentOS 7

Thereafter, you need to resolves RPM packages by executing the command.

# yum install rpmconf
# rpmconf -a
Keep Default RPM Settings
Keep Default RPM Settings

Next, perform a clean-up of all the packages you don’t require.

# package-cleanup --leaves
# package-cleanup --orphans
Clean RPM Packages
Clean RPM Packages

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
Install dnf in CentOS 7
Install dnf in CentOS 7

You also need to remove the yum package manager using the command.

# dnf -y remove yum yum-metadata-parser
# rm -Rf /etc/yum
Remove Yum in CentOS 7
Remove Yum in CentOS 7

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
Upgrade CentOS 7
Upgrade CentOS 7

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 http://mirror.centos.org/centos/8/BaseOS/x86_64/os/Packages/centos-linux-release-8.3-1.2011.el8.noarch.rpm http://mirror.centos.org/centos/8/BaseOS/x86_64/os/Packages/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
Upgrade EPEL Repository
Upgrade EPEL Repository

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
CentOS 8 System Upgrade
CentOS 8 System Upgrade

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
Install Kernel in CentOS 8
Install Kernel in CentOS 8

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
Check CentOS Version
Check CentOS Version

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.

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147 thoughts on “How to Upgrade CentOS 7 to CentOS 8”

  1. Had to add “–allowerasing” to make mine work?

    # dnf install --allowerasing http://mirror.centos.org/centos/8/BaseOS/x86_64/os/Packages/centos-linux-repos-8-2.el8.noarch.rpm http://mirror.centos.org/centos/8/BaseOS/x86_64/os/Packages/centos-linux-release-8.3-1.2011.el8.noarch.rpm http://mirror.centos.org/centos/8/BaseOS/x86_64/os/Packages/centos-gpg-keys-8-2.el8.noarch.rpm
    

    Also, change “upgrade” to “install“.

    # dnf -y upgrade https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm
    
    Reply
  2. I had the same problem and found a workaround:

    disable AppStream repo

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

    enable AppStream repo

    # dnf -y --releasever=8 --allowerasing --setopt=deltarpm=false distro-sync
    
    Reply
    • Thanks for the fix here is the command I used to get it to work:

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

      After the installation, I also ran:

      # dnf update -y
      # dnf install kernel
      

      Everything looks good after the reboot now, thanks again.

      Reply
  3. I have upgraded centos 7.9 to centos 8.3.2011,

    but it is still showing old kernel version.

    [[email protected] 18:12:48 boot]# uname -srv
    Linux 3.10.0-693.el7.x86_64 #1 SMP Tue Aug 22 21:09:27 UTC 2017
    
    [[email protected] 18:13:04 boot]# rpm -qa | grep kernel | sort
    kernel-4.18.0-240.10.1.el8_3.x86_64
    kernel-core-4.18.0-240.10.1.el8_3.x86_64
    kernel-headers-4.18.0-240.10.1.el8_3.x86_64
    kernel-modules-4.18.0-240.10.1.el8_3.x86_64
    kernel-tools-4.18.0-240.10.1.el8_3.x86_64
    kernel-tools-libs-4.18.0-240.10.1.el8_3.x86_64
    
    Reply
  4. Alfista – You may see a section like “weak dependencies” that includes some of the packages that require these dependencies. Python3 and Perl stuff has to be removed.

    Reply
  5. Hope to see the same guide for an upgrade from CentOS 7 to Rocky Linux 8 when will be available, this will save a lot of work in migration

    Reply
    • @Luca,

      Sure, once Rocky Linux 8 available, if instructions are there to upgrade from CentOS to Rocky Linux, will surely publish the guide on same..

      Reply
  6. Hi,

    I have a problem with transaction check:

    Running transaction check
    Error: transaction check vs depsolve:
    (gcc >= 8 with gcc < 9) is needed by annobin-9.23-1.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
    (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'.

    Please can you help me?

    Thanks.

    Reply
      • Will, it does not delete all repositories? While I have follower one solution here on the net and the result was deleting all repositories and then I needed to add it manually and it was hard to get and install it back.

        Thanks.

        Reply

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