Appendix

Here you will find supplementary information that is very good to know and will likely prove to helpful for anyone who is going to be building RPMs in an serious capacity but isn’t necessarily a hard requirement to learn how to package RPMs in the first place which is what the main goal of this document is.

Mock

Mock is a tool for building packages. It can build packages for different architectures and different Fedora or RHEL versions than the build host has. Mock creates chroots and builds packages in them. Its only task is to reliably populate a chroot and attempt to build a package in that chroot.

Mock also offers a multi-package tool, mockchain, that can build chains of packages that depend on each other.

Mock is capable of building SRPMs from source configuration management if the mock-scm package is present, then building the SRPM into RPMs. See –scm-enable in the documentation.” (From the upstream documentation)

Note

In order to use Mock on a RHEL or CentOS system, you will need to enable the “Extra Packages for Enterprise Linux” (EPEL) repository. This is a repository provided by the Fedora community and has many useful tools for RPM Packagers, systems administrators, and developers.

One of the most common use cases RPM Packagers have for Mock is to create what is known as a “pristine build environment”. By using mock as a “pristine build environment”, nothing about the current state of your system has an effect on the RPM Package itself. Mock uses different configurations to specify what the build “target” is, these are found on your system in the /etc/mock/ directory (once you’ve installed the mock package). You can build for different distributions or releases just by specifying it on the command line. Something to keep in mind is that the configuration files the come with mock are targeted at Fedora RPM Packagers and as such RHEL and CentOS release versions are labeled as “epel” because that is the “target” repository these RPMs would be built for. You simply specify the configuration you want to use (minus the .cfg file extension). For example, you could build our cello example for both RHEL 7 and Fedora 23 using the following commands without ever having to use different machines.

$ mock -r epel-7-x86_64 ~/rpmbuild/SRPMS/cello-1.0-1.el7.src.rpm

$ mock -r fedora-23-x86_64 ~/rpmbuild/SRPMS/cello-1.0-1.el7.src.rpm

One example of why you might want to use mock is if you were packaging RPMs on your laptop and you had a package installed (we’ll call it foo for this example) that was a BuildRequires of that package you were creating but forgot to actually make the BuildRequires: foo entry. The build would succeed when you run rpmbuild because foo was needed to build and it was found on the system at build time. However, if you took the SRPM to another system that lacked foo it would fail, causing an unexpected side effect. Mock solves this by first parsing the contents of the SRPM and installing the BuildRequires into it’s chroot which means that if you were missing the BuildRequires entry the build would fail because mock would not know to install it and it would therefore not be present in the buildroot.

Another example is the opposite scenario, let’s say you need gcc to build a package but don’t have it installed on your system (which is unlikely as a RPM Packager, but just for the sake of the example let us pretend that is true). With Mock, you don’t have to install gcc on your system because it will get installed in the chroot as part of mock’s process.

Below is an example of attempting to rebuild a package that has a dependency that I’m missing on my system. The key thing to note is that while gcc is commonly on most RPM Packager’s systems, some RPM Packages can have over a dozen BuildRequires and this allows you to not need to clutter up your workstation with otherwise un-needed or un-necessary packages.

$ rpmbuild --rebuild ~/rpmbuild/SRPMS/cello-1.0-1.el7.src.rpm
Installing /home/admiller/rpmbuild/SRPMS/cello-1.0-1.el7.src.rpm
error: Failed build dependencies: gcc is needed by cello-1.0-1.el7.x86_64

$ mock -r epel-7-x86_64 ~/rpmbuild/SRPMS/cello-1.0-1.el7.src.rpm
INFO: mock.py version 1.2.17 starting (python version = 2.7.5)...
Start: init plugins
INFO: selinux enabled
Finish: init plugins
Start: run
INFO: Start(/home/admiller/rpmbuild/SRPMS/cello-1.0-1.el7.src.rpm)  Config(epel-7-x86_64)
Start: clean chroot
Finish: clean chroot
Start: chroot init
INFO: calling preinit hooks
INFO: enabled root cache
Start: unpacking root cache
Finish: unpacking root cache
INFO: enabled yum cache
Start: cleaning yum metadata
Finish: cleaning yum metadata
Mock Version: 1.2.17
INFO: Mock Version: 1.2.17
Start: yum update
base                                                                    | 3.6 kB  00:00:00
epel                                                                    | 4.3 kB  00:00:00
extras                                                                  | 3.4 kB  00:00:00
updates                                                                 | 3.4 kB  00:00:00
No packages marked for update
Finish: yum update
Finish: chroot init
Start: build phase for cello-1.0-1.el7.src.rpm
Start: build setup for cello-1.0-1.el7.src.rpm
warning: Could not canonicalize hostname: rhel7
Building target platforms: x86_64
Building for target x86_64
Wrote: /builddir/build/SRPMS/cello-1.0-1.el7.centos.src.rpm
Getting requirements for cello-1.0-1.el7.centos.src
 --> Already installed : gcc-4.8.5-4.el7.x86_64
 --> Already installed : 1:make-3.82-21.el7.x86_64
No uninstalled build requires
Finish: build setup for cello-1.0-1.el7.src.rpm
Start: rpmbuild cello-1.0-1.el7.src.rpm
Building target platforms: x86_64
Building for target x86_64
Executing(%prep): /bin/sh -e /var/tmp/rpm-tmp.v9rPOF
+ umask 022
+ cd /builddir/build/BUILD
+ cd /builddir/build/BUILD
+ rm -rf cello-1.0
+ /usr/bin/gzip -dc /builddir/build/SOURCES/cello-1.0.tar.gz
+ /usr/bin/tar -xf -
+ STATUS=0
+ '[' 0 -ne 0 ']'
+ cd cello-1.0
+ /usr/bin/chmod -Rf a+rX,u+w,g-w,o-w .
Patch #0 (cello-output-first-patch.patch):
+ echo 'Patch #0 (cello-output-first-patch.patch):'
+ /usr/bin/cat /builddir/build/SOURCES/cello-output-first-patch.patch
patching file cello.c
+ /usr/bin/patch -p0 --fuzz=0
+ exit 0
Executing(%build): /bin/sh -e /var/tmp/rpm-tmp.UxRVtI
+ umask 022
+ cd /builddir/build/BUILD
+ cd cello-1.0
+ make -j2
gcc -o cello cello.c
+ exit 0
Executing(%install): /bin/sh -e /var/tmp/rpm-tmp.K3i2dL
+ umask 022
+ cd /builddir/build/BUILD
+ '[' /builddir/build/BUILDROOT/cello-1.0-1.el7.centos.x86_64 '!=' / ']'
+ rm -rf /builddir/build/BUILDROOT/cello-1.0-1.el7.centos.x86_64
++ dirname /builddir/build/BUILDROOT/cello-1.0-1.el7.centos.x86_64
+ mkdir -p /builddir/build/BUILDROOT
+ mkdir /builddir/build/BUILDROOT/cello-1.0-1.el7.centos.x86_64
+ cd cello-1.0
+ /usr/bin/make install DESTDIR=/builddir/build/BUILDROOT/cello-1.0-1.el7.centos.x86_64
mkdir -p /builddir/build/BUILDROOT/cello-1.0-1.el7.centos.x86_64/usr/bin
install -m 0755 cello /builddir/build/BUILDROOT/cello-1.0-1.el7.centos.x86_64/usr/bin/cello
+ /usr/lib/rpm/find-debuginfo.sh --strict-build-id -m --run-dwz --dwz-low-mem-die-limit 10000000 --dwz-max-die-limit 110000000 /builddir/build/BUILD/cello-1.0
extracting debug info from /builddir/build/BUILDROOT/cello-1.0-1.el7.centos.x86_64/usr/bin/cello
dwz: Too few files for multifile optimization
/usr/lib/rpm/sepdebugcrcfix: Updated 0 CRC32s, 1 CRC32s did match.
+ /usr/lib/rpm/check-buildroot
+ /usr/lib/rpm/redhat/brp-compress
+ /usr/lib/rpm/redhat/brp-strip-static-archive /usr/bin/strip
+ /usr/lib/rpm/brp-python-bytecompile /usr/bin/python 1
+ /usr/lib/rpm/redhat/brp-python-hardlink
+ /usr/lib/rpm/redhat/brp-java-repack-jars
Processing files: cello-1.0-1.el7.centos.x86_64
Executing(%license): /bin/sh -e /var/tmp/rpm-tmp.vxtAuO
+ umask 022
+ cd /builddir/build/BUILD
+ cd cello-1.0
+ LICENSEDIR=/builddir/build/BUILDROOT/cello-1.0-1.el7.centos.x86_64/usr/share/licenses/cello-1.0
+ export LICENSEDIR
+ /usr/bin/mkdir -p /builddir/build/BUILDROOT/cello-1.0-1.el7.centos.x86_64/usr/share/licenses/cello-1.0
+ cp -pr LICENSE /builddir/build/BUILDROOT/cello-1.0-1.el7.centos.x86_64/usr/share/licenses/cello-1.0
+ exit 0
Provides: cello = 1.0-1.el7.centos cello(x86-64) = 1.0-1.el7.centos
Requires(rpmlib): rpmlib(CompressedFileNames) <= 3.0.4-1 rpmlib(FileDigests) <= 4.6.0-1 rpmlib(PayloadFilesHavePrefix) <= 4.0-1
Requires: libc.so.6()(64bit) libc.so.6(GLIBC_2.2.5)(64bit) rtld(GNU_HASH)
Processing files: cello-debuginfo-1.0-1.el7.centos.x86_64
Provides: cello-debuginfo = 1.0-1.el7.centos cello-debuginfo(x86-64) = 1.0-1.el7.centos
Requires(rpmlib): rpmlib(FileDigests) <= 4.6.0-1 rpmlib(PayloadFilesHavePrefix) <= 4.0-1 rpmlib(CompressedFileNames) <= 3.0.4-1
Checking for unpackaged file(s): /usr/lib/rpm/check-files /builddir/build/BUILDROOT/cello-1.0-1.el7.centos.x86_64
Wrote: /builddir/build/RPMS/cello-1.0-1.el7.centos.x86_64.rpm
warning: Could not canonicalize hostname: rhel7
Wrote: /builddir/build/RPMS/cello-debuginfo-1.0-1.el7.centos.x86_64.rpm
Executing(%clean): /bin/sh -e /var/tmp/rpm-tmp.JuPOtY
+ umask 022
+ cd /builddir/build/BUILD
+ cd cello-1.0
+ /usr/bin/rm -rf /builddir/build/BUILDROOT/cello-1.0-1.el7.centos.x86_64
+ exit 0
Finish: rpmbuild cello-1.0-1.el7.src.rpm
Finish: build phase for cello-1.0-1.el7.src.rpm
INFO: Done(/home/admiller/rpmbuild/SRPMS/cello-1.0-1.el7.src.rpm) Config(epel-7-x86_64) 0 minutes 16 seconds
INFO: Results and/or logs in: /var/lib/mock/epel-7-x86_64/result
Finish: run

As you can see, mock is a fairly verbose tool. You will also notice a lot of yum or dnf output (depending on RHEL7, CentOS7, or Fedora mock target) that is not found in this output which was omitted for brevity and is often omitted after you have done an --init on a mock target, such as mock -r epel-7-x86_64 --init which will pre-download all the required packages, cache them, and pre-stage the build chroot.

For more information, please consult the Mock upstream documentation.

Version Control Systems

When working with RPMs, it is often desireable to utilize a Version Control System (VCS) such as git for managing components of the software we are packaging. Something to note is that storing binary files in a VCS is not favorable because it will drastically inflate the size of the source repository as these tools are engineered to handle differentials in files (often optimized for text files) and this is not something that binary files lend themselves to so normally each whole binary file is stored. As a side effect of this there are some clever utilities that are popular among upstream Open Source projects that work around this problem by either storing the SPEC file where the source code is in a VCS (i.e. - it is not in a compressed archive for redistribution) or place only the SPEC file and patches in the VCS and upload the compressed archive of the upstream release source to what is called a “look aside cache”.

In this section we will cover two different options for using a VCS system, git, for managing the contents that will ultimately be turned into a RPM package. One is called tito and the other is dist-git.

Note

For the duration of this section you will need to install the git package on you system in order to follow along.

tito

Tito is an utility that assumes all the source code for the software that is going to be packaged is already in a git source control repository. This is good for those practicing a DevOps workflow as it allows for the team writing the software to maintain their normal Branching Workflow. Tito will then allow for the software to be incrementally packaged, built in an automated fashion, and still provide a native installation experience for RPM based systems.

Note

The tito package is available in Fedora as well as in the EPEL repository for use on RHEL 7 and CentOS 7.

Tito operates based on git tags and will manage tags for you if you elect to allow it, but can optionally operate under whatever tagging scheme you prefer as this functionality is configurable.

Let’s explore a little bit about tito by looking at an upstream project already using it. We will actually be using the upstream git repository of the project that is our next section’s subject, dist-git. Since this project is publicly hosted on is publicly hosted on GitHub, let’s go ahead and clone the git repo.

$ git clone https://github.com/release-engineering/dist-git.git
Cloning into 'dist-git'...
remote: Counting objects: 425, done.
remote: Total 425 (delta 0), reused 0 (delta 0), pack-reused 425
Receiving objects: 100% (425/425), 268.76 KiB | 0 bytes/s, done.
Resolving deltas: 100% (184/184), done.
Checking connectivity... done.

$ cd dist-git/

$ ls *.spec
dist-git.spec

$ tree rel-eng/
rel-eng/
├── packages
│   └── dist-git
└── tito.props

1 directory, 2 files

As we can see here, the SPEC file is at the root of the git repository and there is a rel-eng directory in the repository which is used by tito for general book keeping, configuration, and various advanced topics like custom tito modules. We can see in the directory layout that there is a sub-directory entitled packages which will store a file per package that tito manages in the repository as you can have many RPMs in a single git repository and tito will handle that just fine. In this scenario however, we see only a single package listing and it should be noted that it matches the name of our SPEC file. All of this is setup by the command tito init when the developers of dist-git first initialized their git repo to be managed by tito.

If we were to follow a common workflow of a DevOps Practitioner then we would likely want to use this as part of a Continuous Integration (CI) or Continuous Delivery (CD) process. What we can do in that scenario is perform what is known as a “test build” to tito, we can even use mock to do this. We could then use the output as the installation point for some other component in the pipeline. Below is a simple example of commands that could accomplish this and they could be adapted to other environments.

$ tito build --test --srpm
Building package [dist-git-0.13-1]
Wrote: /tmp/tito/dist-git-git-0.efa5ab8.tar.gz

Wrote: /tmp/tito/dist-git-0.13-1.git.0.efa5ab8.fc23.src.rpm

$ tito build --builder=mock --arg mock=epel-7-x86_64 --test --rpm
Building package [dist-git-0.13-1]
Creating rpms for dist-git-git-0.efa5ab8 in mock: epel-7-x86_64
Wrote: /tmp/tito/dist-git-git-0.efa5ab8.tar.gz

Wrote: /tmp/tito/dist-git-0.13-1.git.0.efa5ab8.fc23.src.rpm


Using srpm: /tmp/tito/dist-git-0.13-1.git.0.efa5ab8.fc23.src.rpm
Initializing mock...
Installing deps in mock...
Building RPMs in mock...
Wrote:
  /tmp/tito/dist-git-selinux-0.13-1.git.0.efa5ab8.el7.centos.noarch.rpm
  /tmp/tito/dist-git-0.13-1.git.0.efa5ab8.el7.centos.noarch.rpm

$ sudo yum localinstall /tmp/tito/dist-git-*.noarch.rpm
Loaded plugins: product-id, search-disabled-repos, subscription-manager
Examining /tmp/tito/dist-git-0.13-1.git.0.efa5ab8.el7.centos.noarch.rpm: dist-git-0.13-1.git.0.efa5ab8.el7.centos.noarch
Marking /tmp/tito/dist-git-0.13-1.git.0.efa5ab8.el7.centos.noarch.rpm to be installed
Examining /tmp/tito/dist-git-selinux-0.13-1.git.0.efa5ab8.el7.centos.noarch.rpm: dist-git-selinux-0.13-1.git.0.efa5ab8.el7.centos.noarch
Marking /tmp/tito/dist-git-selinux-0.13-1.git.0.efa5ab8.el7.centos.noarch.rpm to be installed
Resolving Dependencies
--> Running transaction check
---> Package dist-git.noarch 0:0.13-1.git.0.efa5ab8.el7.centos will be installed

Note that the final command would need to be run with either sudo or root permissions and that much of the output has been omitted for brevity as the dependency list is quite long.

This concludes our simple example of how to use tito but it has many amazing features for traditional Systems Administrators, RPM Packagers, and DevOps Practitioners alike. I would highly recommend consulting the upstream documentation found at the tito GitHub site for more information on how to quickly get started using it for your project as well as various advanced features it offers.

dist-git

The dist-git utility takes a slightly different approach from that of tito such that instead of keeping the raw source code in git it instead will keep SPEC files and patches in a git repository and upload the compressed archive of the source code to what is known as a “look-aside cache”. The “look-aside-cache” is a term that was coined by the use of RPM Build Systems storing large files like these “on the side”. A system like this is generally tied to a proper RPM Build System such as Koji. The build system is then configured to pull the items that are listed as SourceX entries in the SPEC files in from this look-aside-cache, while the SPEC and patches remain in a version control system. There is also a helper command line tool to assist in this.

In an effort to not duplicate documentation, for more information on how to setup a system such as this please refer to the upstream dist-git docs. upstream docs.

More on Macros

There are many built-in RPM Macros and we will cover a few in the following section, however an exhaustive list can be found rpm.org’s rpm macro official documentation.

There are also macros that are provided by your Linux Distribution, we will cover some of those provided by Fedora, CentOS and RHEL in this section as well as provide information on how to inspect your system to learn about others that we don’t cover or for discovering them on other RPM-based Linux Distributions.

Defining Your Own

You can define your own Macros, below is an excerpt from the RPM Official Documentation and I recommend anyone interested in an exhaustive explanation of the many possibilities of defining their own macros to visit that resource. It’s really quite good and there’s little reason to duplicate the bulk of that content here.

To define a macro use:

%define <name>[(opts)] <body>

All whitespace surrounding \<body\> is removed. Name may be composed of alphanumeric characters, and the character _ and must be at least 3 characters in length. A macro without an (opts) field is “simple” in that only recursive macro expansion is performed. A parameterized macro contains an (opts) field. The opts (i.e. string between parentheses) is passed exactly as is to getopt(3) for argc/argv processing at the beginning of a macro invocation.

%files

Common “advanced” RPM Macros needed in the %files section are as follows:

Macro Definition
%license This identifies the file listed as a LICENSE file and it will be installed and labeled as such by RPM. Example: %license LICENSE
%doc This identifies the file listed as documentation and it will be installed and labeled as such by RPM. This is often used not only for documentation about the software being packaged but also code examples and various items that should accompany documentation. In the event code examples are included, care should be taken to remove executable mode from the file. Example: %doc README
%dir Identifies that the path is a directory that should be owned by this RPM. This is important so that the rpm file manifest accurately knows what directories to clean up on uninstall. Example: %dir %{_libdir}/%{name}
%config(noreplace) Specifies that the following file is a configuration file and therefore should not be overwritten (or replaced) on a package install or update if the file has been modified from the original installation checksum. In the event that there is a change, the file will be created with .rpmnew appended to the end of the filename upon upgrade or install so that the pre-existing or modified file on the target system is not modified. Example: %config(noreplace) %{_sysconfdir}/%{name}/%{name}.conf

Built In Macros

Your system has many built in RPM Macros and the fastest way to view them all is to simply run the rpm --showrc command, however note that this will contain a lot of output so it’s often used in combination with a pipe to grep (or a clever shell Process Substitution).

You can also find information about the RPMs macros that come directly with your system’s version of RPM by looking at the output of the command rpm -ql rpm taking note of the files titled macros in the directory structure.

RPM Distribution Macros

Different distributions will supply different sets of recommended RPM Macros based on the language implementation of the software being packaged or the specific Guidelines of the distribution in question.

These are often provided as RPM Packages themselves and can be installed with the distribution package manager, such as yum or dnf. The macro files themselves once installed can be found in /usr/lib/rpm/macros.d/ and will be included in the rpm --showrc output by default once installed.

One primary example of this is the Fedora Packaging Guidelines section pertaining specifically to Application Specific Guidelines which at the time of this writing has over 30 different sets of guidelines along with associated RPM Macro sets for subject matter specific RPM Packaging.

One example of these kinds of RPMs would be for Python version 2.x and if we have the python2-rpm-macros package installed (available in EPEL for RHEL 7 and CentOS 7), we have a number of python2 specific macros available to us.

$ rpm -ql python2-rpm-macros
/usr/lib/rpm/macros.d/macros.python2


$ rpm --showrc | grep python2
-14: __python2  /usr/bin/python2
CFLAGS="%{optflags}" %{__python2} %{py_setup} %{?py_setup_args} build --executable="%{__python2} %{py2_shbang_opts}" %{?1}
CFLAGS="%{optflags}" %{__python2} %{py_setup} %{?py_setup_args} install -O1 --skip-build --root %{buildroot} %{?1}
-14: python2_sitearch   %(%{__python2} -c "from distutils.sysconfig import get_python_lib; print(get_python_lib(1))")
-14: python2_sitelib    %(%{__python2} -c "from distutils.sysconfig import get_python_lib; print(get_python_lib())")
-14: python2_version    %(%{__python2} -c "import sys; sys.stdout.write('{0.major}.{0.minor}'.format(sys.version_info))")
-14: python2_version_nodots     %(%{__python2} -c "import sys; sys.stdout.write('{0.major}{0.minor}'.format(sys.version_info))")

The above output displays the raw RPM Macro definitions, but we are likely more interested in what these will evaluate to which we can do with rpm --eval in order to determine what they do as well as how they may be helpful to us when packaging RPMs.

$ rpm --eval %{__python2}
/usr/bin/python2

$ rpm --eval %{python2_sitearch}
/usr/lib64/python2.7/site-packages

$ rpm --eval %{python2_sitelib}
/usr/lib/python2.7/site-packages

$ rpm --eval %{python2_version}
2.7

$ rpm --eval %{python2_version_nodots}
27

Advanced SPEC File Topics

There are various topics in the world of RPM SPEC Files that are considered advanced because they have implications on not only the SPEC file, how the package is built, but also on the end machine that the resulting RPM is installed upon. In this section we will cover the most common of these such as Epoch, Scriptlets, and Triggers.

Epoch

First on the list is Epoch, epoch is a way to define weighted dependencies based on version numbers. It’s default value is 0 and this is assumed if an Epoch directive is not listed in the RPM SPEC file. This was not covered in the SPEC File section of this guide because it is almost always a bad idea to introduce an Epoch value as it will skew what you would normally otherwise expect RPM to do when comparing versions of packages.

For example if a package foobar with Epoch: 1 and Version: 1.0 was installed and someone else packaged foobar with Version: 2.0 but simply omitted the Epoch directive either because they were unaware of it’s necessity or simply forgot, that new version would never be considered an update because the Epoch version would win out over the traditional Name-Version-Release marker that signifies versioning for RPM Packages.

This approach is generally only used when absolutely necessary (as a last resort) to resolve an upgrade ordering issue which can come up as a side effect of upstream software changing versioning number schemes or versions incorporating alphabetical characters that can not always be compared reliably based on encoding.

Triggers and Scriptlets

In RPM Packages, there are a series of directives that can be used to inflict necessary or desired change on a system during install time of the RPM. These are called scriptlets.

One primary example of when and why you’d want to do this is when a system service RPM is installed and it provides a systemd unit file. At install time we will need to notify systemd that there is a new unit so that the system administrator can run a command similar to systemctl start foo.service after the fictional RPM foo (which provides some service daemon in this example) has been installed. Similarly, we would need to inverse of this action upon uninstallation so that an administrator would not get errors due to the daemon’s binary no longer being installed but the unit file still existing in systemd’s running configuration.

There are a small handful of common scriptlet directives, they are similar to the “section headers” like %build or %install in that they are defined by multi-line segments of code, often written as standard POSIX shell script but can be a few different programming languages such that RPM for the target machine’s distribution is configured to allow them. An exhaustive list of these available languages can be found in the RPM Official Documentation.

Scriptlet directives are as follows:

Directive Definition
%pre Scriptlet that is executed just before the package is installed on the target system.
%post Scriptlet that is executed just after the package is installed on the target system.
%preun Scriptlet that is executed just before the package is uninstalled from the target system.
%postun Scriptlet that is executed just after the package is uninstalled from the target system.

Is is also common for RPM Macros to exist for this function. In our previous example we discussed systemd needing to be notified about a new unit file, this is easily handled by the systemd scriptlet macros as we can see from the below example output. More information on this can be found in the Fedora systemd Packaging Guidelines.

$ rpm --showrc | grep systemd
-14: __transaction_systemd_inhibit      %{__plugindir}/systemd_inhibit.so
-14: _journalcatalogdir /usr/lib/systemd/catalog
-14: _presetdir /usr/lib/systemd/system-preset
-14: _unitdir   /usr/lib/systemd/system
-14: _userunitdir       /usr/lib/systemd/user
/usr/lib/systemd/systemd-binfmt %{?*} >/dev/null 2>&1 || :
/usr/lib/systemd/systemd-sysctl %{?*} >/dev/null 2>&1 || :
-14: systemd_post
-14: systemd_postun
-14: systemd_postun_with_restart
-14: systemd_preun
-14: systemd_requires
Requires(post): systemd
Requires(preun): systemd
Requires(postun): systemd
-14: systemd_user_post  %systemd_post --user --global %{?*}
-14: systemd_user_postun        %{nil}
-14: systemd_user_postun_with_restart   %{nil}
-14: systemd_user_preun
systemd-sysusers %{?*} >/dev/null 2>&1 || :
echo %{?*} | systemd-sysusers - >/dev/null 2>&1 || :
systemd-tmpfiles --create %{?*} >/dev/null 2>&1 || :

$ rpm --eval %{systemd_post}

if [ $1 -eq 1 ] ; then
        # Initial installation
        systemctl preset  >/dev/null 2>&1 || :
fi

$ rpm --eval %{systemd_postun}

systemctl daemon-reload >/dev/null 2>&1 || :

$ rpm --eval %{systemd_preun}

if [ $1 -eq 0 ] ; then
        # Package removal, not upgrade
        systemctl --no-reload disable  > /dev/null 2>&1 || :
        systemctl stop  > /dev/null 2>&1 || :
fi

Another item that provides even more fine grained control over the RPM Transaction as a whole is what is known as triggers. These are effectively the same thing as a scriptlet but are executed in a very specific order of operations during the RPM install or upgrade transaction allowing for a more fine grained control over the entire process.

The order in which each is executed and the details of which are provided below.

all-%pretrans
...
any-%triggerprein (%triggerprein from other packages set off by new install)
new-%triggerprein
new-%pre      for new version of package being installed
...           (all new files are installed)
new-%post     for new version of package being installed

any-%triggerin (%triggerin from other packages set off by new install)
new-%triggerin
old-%triggerun
any-%triggerun (%triggerun from other packages set off by old uninstall)

old-%preun    for old version of package being removed
...           (all old files are removed)
old-%postun   for old version of package being removed

old-%triggerpostun
any-%triggerpostun (%triggerpostun from other packages set off by old un
            install)
...
all-%posttrans

The above items are from the included RPM documentation found in /usr/share/doc/rpm/triggers on Fedora systems and /usr/share/doc/rpm-4.*/triggers on RHEL 7 and CentOS 7 systems.

References

Below are references to various topics of interest around RPMs, RPM Packaging, and RPM Building. Some of these will be advanced and extend far beyond the introductory material included in this guide.