Linux servers.

Upgrading Red Hat Enterprise Linux / CentOS / Oracle Linux

RHEL/CentOS/Oracle Linux Migration
Package Management with rpm and yum/dnf
Building Software From Source

There have been only minor changes in software package management and the task of building software from source. The biggest change hasn't been within Linux itself, but has been the Internet locations of the major free software archives.

Previous: Storage

The previous page explained how storage has changed as the default file system type has migrated from Ext3 to Ext4 to XFS and possibly to Btrfs depending on the distribution.

6 — Package Management

RHEL 5.* gave you both IA32 and IA64 binaries and libraries for most packages when you install onto 64-bit hardware. Put another way, starting with RHEL 6 you no longer get two lines of output when you type:

$ rpm -q firefox

and so you no longer have to type this to figure it out:

$ rpm -q --qf '%{name}.%{arch}\n' firefox
Package Management

See my page on package management for details on rpm and yum, as well as other Linux package systems like the Debian and Ubuntu apt-get and dpkg and the Mageia urpm system, plus OpenBSD and Solaris package management.

BaseOS versus AppStream

With RHEL 8, the packages are split into BaseOS versus AppStream. On the DVD image they are top-level directories, each with subdirectories Packages and repodata, so they function as two separate package repositories.

yum versus dnf

The dnf program has replaced yum, but you won't notice the difference! With RHEL 8, /usr/bin/yum is a symbolic link to dnf-3. The command syntax, and result of using the command, remains the same. The upgrade from yum to dnf replaced the "engine" that works out the dependencies. The new version should run much faster while giving the same results.

7 — Building Software from Source

Starting with RHEL 6, rpmbuild and related tools no longer use directories under /usr/src/ as their working area. They instead use ~/rpmbuild, meaning that things like building a kernel as root requires an unusually large amount of space on the / partition. That is, unless you do this:

# mkdir /usr/src/rpmbuild
# ln -s /usr/src/rpmbuild ~/rpmbuild

For reasons completely unrelated to any specific Linux distribution, the standard free software web sites have changed. Formerly useful sites like,,, and have been replaced by GitHub and, to a limited extent, RPM Fusion. Although, somewhat useful versions of Sourceforge and Freecode may be back...

The next section is on networking, an area that really changed between RHEL 6 and 7.

Next ❯ Networking