We’re 60 episodes in, and today we’re getting back to one of the most fundamental tasks in systems management, package management.
In this episode we look at three new dnf-related improvements for managing packages on Enterprise Linux (Red Hat, Rocky Linux , AlmaLinux).
We walk through the new dnf and dnf_group package modules, and the appstreams custom promise type.
Why new package modules?
The existing yum package module works, but it shells out to run commands. The new dnf module takes a different approach: it uses the dnf and rpm Python libraries directly. This matters for security, reliability, and performance on modern Enterprise Linux where dnf has replaced yum as the native package manager.
Both dnf and dnf_group are merged into the maintained branches (3.27.x and 3.24.x) but not yet the default for any platform, you will need to explicitly specify package_module => dnf or package_module => dnf_group. The appstreams custom promise type is available from CFEngine Build.
The dnf package module
The dnf module handles individual packages:
bundle agent dnf_examples
{
packages:
"vim-enhanced"
policy => "present",
package_module => dnf,
version => "8.2.2637-23.el9_7.1";
"httpd"
policy => "present",
version => "latest",
package_module => dnf;
"emacs-nox"
policy => "present",
package_module => dnf;
}To integrate it before the next release, you need the dnf.mustache module and
the associated body definition.
The dnf_group package module
The dnf_group package module lets you manage a curated set of packages as a single unit.
bundle agent dnf_group_example
{
packages:
"development"
policy => "present",
package_module => dnf_group,
options => {
"group_package_types=mandatory,default,optional",
"install_weak_deps=false"
},
version => "latest";
}The options attribute controls which package types within the group get installed (mandatory, default, optional) and whether weak dependencies are pulled in.
This gives you fine-grained control over what a group actually installs on your systems.
AppStreams promise type
AppStreams help to solve the issue where you need PHP 8.3 on one set of hosts and PHP 8.1 on another, from the same OS repositories. AppStreams let multiple versions coexist and you pick which stream to enable.
The appstreams promise type is available via CFEngine Build:
cfbs add promise-type-appstreamsOr using the shorter alias:
cfbs add appstreamsThen in policy:
bundle agent appstreams_example
{
appstreams:
"php"
state => "installed",
stream => "8.3",
profile => "minimal",
options => {"install_weak_deps=false"};
}This ensures PHP is installed from the 8.3 stream using the minimal profile. Unlike the package modules, the appstreams promise type is a custom module distributed through CFEngine Build, not vendored in masterfiles.
Video
The video recording is available on YouTube:
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