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As containers have become the new de facto standard for packaging applications and their dependencies, ie D
understanding how to implement, build, and manage them is now an essential skill for developers, system llo e
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administrators, and SRE/operations teams. Podman and its companion tools Buildah and Skopeo make a G O
ia p for DevOps
great toolset to boost the development, execution, and management of containerized applications. n s
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Starting with the basic concepts of containerization and its underlying technology, this book will help i S
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you get your fi rst container up and running with Podman. You’ll explore the complete toolkit and go over lin
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the development of new containers, their lifecycle management, troubleshooting, and security aspects. tt
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Together with Podman, the book illustrates Buildah and Skopeo to complete the tools ecosystem and
cover the complete workfl ow for building, releasing, and managing optimized container images. Podman
for DevOps provides a comprehensive view of the full-stack container technology and its relationship Containerization reimagined with Podman and its
with the operating system foundations, along with crucial topics such as networking, monitoring, and
companion tools
integration with systemd, docker-compose, and Kubernetes.
By the end of this DevOps book, you’ll have developed the skills needed to build and package your
applications inside containers as well as to deploy, manage, and integrate them with system services.
Things you will learn:
• Understand Podman's daemonless • Manage OCI images with Skopeo
approach as a container engine • Troubleshoot runtime, build, and
• Run, manage, and secure containers isolation issues
with Podman • Integrate Podman containers
• Discover the strategies, concepts, with existing networking and
and command-line options for system services
using Buildah to build containers
from scratch
Alessandro Arrichiello | Gianni Salinetti
Foreword by Brent J. Baude
Podman for DevOps
Containerization reimagined with Podman and its
companion tools
Alessandro Arrichiello
Gianni Salinetti
BIRMINGHAM—MUMBAI
Podman for DevOps
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To my son, Giovanni, for allowing me to steal time from our playtime. To
my wife, Tecla, for being my loving partner and supporting me.
– Alessandro Arrichiello
To my son, Filippo, who teaches me to learn every day and enjoy the little
things in life. To my beloved wife, Anna Veronica, for all the strength and
inspiration she brings to our family.
– Gianni Salinetti
Foreword
Containers, their various runtimes, and Kubernetes are seeing fierce momentum in
the technology and computing worlds. They are no longer just the darling of system
administrators and Kubernetes distributed workloads. Containers are now endemic in
Continuous Integration (CI) tasks, cloud workloads, and microservices. Starting with
programmers, containers have even broken into the desktop space, where Integrated
Development Environments (IDEs) can be the backend into containers for things such
as testing language versions or compiling code. We can attribute the latest invigoration
to the simplification of container images and the ability to distribute them in container
registries. Not bad for a decades-old technology that used to simply focus on the isolation
of a computing process.
Podman for DevOps begins with a detailed exploration of container history, from its
inception to now. It then transitions into the various container technologies and arrives
at the two most common ones: Docker and Podman (short for Pod Manager). The early
chapters provide a comprehensive examination of Docker and Podman and describe the
pros and cons of both. These comparisons demonstrate Podman's novelty and strengths.
Gianni and Alessandro then settle on Podman, beginning with an exploration of its
architecture. They then follow the architecture by illustrating the various applications in
the Podman stack, such as conmon and network tooling. After laying the groundwork for
how Podman works, they meticulously review each Podman command in an example-
oriented approach. Finally, Gianni and Alessandro provide a thorough review of Buildah,
Podman's best friend and a best-of-breed application for building container images.
When I write about containers and Podman, one of my challenges when explaining
concepts can be providing too many details or oversimplifying things. Gianni and
Alessandro have found a perfect medium between both ends by supplying ample amounts
of detail. I appreciated the carefully crafted explanations when the topic required them.
Not only was the level of detail appropriate, but they also used a very wide scope when
writing about Podman and containers. As I read the book, I was able to relate to their
superb use of examples and they did not add layers of abstraction that can make learning
difficult. Podman for DevOps was a pleasure to read. As a subject matter expert, I am
certain it will be a perfect resource for those both new to and experienced with Podman
and containers.
Brent J. Baude, Senior Principal Software Engineer
Podman Architect
Contributors
About the authors
Alessandro Arrichiello is a solution architect for Red Hat Inc. with a special focus on
telco technologies. He has a passion for GNU/Linux systems, which began at age 14 and
continues today. He has worked with tools for automating enterprise IT: configuration
management and continuous integration through virtual platforms. Alessandro is also a
writer for the Red Hat Developer Blog, on which he has authored several articles about
container architecture and technology. He now helps telecommunication customers
with adopting container orchestration environments such as Red Hat OpenShift and
Kubernetes, infrastructure as a service such as OpenStack, edge computing, and data
center automation.
Gianni Salinetti is a solution architect from Rome working for Red Hat Inc. with a special
focus on cloud-native computing and hybrid cloud strategies. He started working with
GNU/Linux back in 2001 and developed a passion for open source software. His main
fields of interest are application orchestration, automation, and systems performance
tuning. He is also an advocate of DevSecOps and GitOps practices. He is a former Red Hat
instructor, having taught many classes about GNU/Linux, OpenStack, JBoss middleware,
Ansible, Kubernetes, and Red Hat OpenShift. He won Red Hat EMEA awards as the
best DevOps, cloud, and middleware instructor. He is also an author for the Red Hat
Developer Blog and actively contributes to webinars and events.
About the reviewers
Nicolò Amato has over 20 years of experience working in the field of IT, 16 of which
were at Hewlett Packard Enterprise, Accenture, DXC, and Red Hat Inc. Working in both
technical and development roles has given him a broad base of skills and the ability to
work with a diverse range of clients. His time was spent designing and implementing
complex infrastructures for clients with the aim to migrate traditional services to hybrid,
multi-cloud, and edge environments, evolving them into cloud-native services. He is
enthusiastic about new technologies and he likes to be up to date – in particular with open
source, which he considers one of the essences of technology that regulates the evolution
of information technology.
Pierluigi Rossi is a solution architect for Red Hat Inc. His passion for GNU/Linux systems
began 20 years ago and continues today. He has built a strong business and technical
know-how on enterprise and cutting-edge technologies, working for many companies
on different verticals and roles in the last 20 years. He has worked with virtualization and
containerization tools (open source and not). He has also participated in several projects
for corporate IT automation. He is now working on distributed on-premises and cloud
environments involving IaaS, PaaS (OpenShift and Kubernetes), and automation. He loves
open source in all its shades, and he enjoys sharing ideas and solutions with customers,
colleagues, and community members.
Marco Alessandro Fagotto has been in the IT industry for 13 years, ranging across
frontend and backend support, administration, system configuration, and security roles.
Working in both technical and development roles has given him a broad base of skills and
the ability to work with a diverse range of clients. He is a Red Hat Certified Professional,
always looking for new technology and solutions to explore due to his interest in the fast
evolution of the open source world.
Table of Contents
Preface
Section 1: From Theory to Practice: Running
Containers with Podman
1
Introduction to Container Technology
Technical requirements 4 Infrastructure optimization 19
Book conventions 4 Microservices 20
Chroot and Unix v7 21
What are containers? 4
FreeBSD jails 21
Resource usage with cgroups 7
Solaris Containers (also known
Running isolated processes 8
as Solaris Zones) 22
Isolating mounts 9
Linux Containers (LXC) 23
Container images to the rescue 10
Docker 25
Security considerations 13
rkt 25
Container engines and runtimes 14
OCI and CRI-O 26
Containers versus virtual machines 15
Podman 27
Why do I need a container? 17
Where are containers
Open source 18 used today? 28
Portability 18
Summary 31
DevOps facilitators 18
Further reading 32
Cloud readiness 19
