Table Of ContentAutomating DevOps with GitLab
CI/CD Pipelines
Build efficient CI/CD pipelines to verify, secure, and deploy your
code using real-life examples
Christopher Cowell
Nicholas Lotz
Chris Timberlake
BIRMINGHAM—MUMBAI
Automating DevOps with GitLab CI/CD Pipelines
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To Marya DeVoto, for reminding me that words actually mean things.
– Christopher Cowell
To my parents, Tom and Deborah, for encouraging me to never stop asking “why?”
– Nicholas Lotz
Contributors
About the authors
Christopher Cowell was formerly a technical trainer at GitLab, and now builds educational content
at Instabase. He also worked for 2 decades as a research scientist, consultant, and QA engineer at
big and small software companies, including Accenture, Oracle, and Puppet. He thinks the software
industry undervalues code quality and thoughtful design and overvalues delivering mediocre code
quickly. Slow down, simplify, and get it right!
He dreams of being able to play every Beatles song on guitar, but would settle for knowing just one
really well. He holds a Ph.D. in philosophy from Berkeley and a B.A. in computer science from Harvard.
He lives in Portland, Oregon, with his wife, his four kids, and the two best cats.
Thank you to my family, for their unending patience whenever I disappeared into the basement to
work on this book, which I did a lot. I especially hope I can repay my wife, Marya DeVoto, by being
just as accommodating when she launches into writing her Space Rabbi series of novels. Soren, I owe
you a ski trip. Kirin, consider yourself to have a lifetime pass for playing Ticket to Ride whenever you
want. Thanks also to my wonderful parents, Nick and Priscilla, for giving me whatever minor skills or
talent I may have at explaining things.
Nicholas Lotz is a technical trainer at GitLab, where he teaches organizations how to use GitLab to
build and ship better software. He previously worked as a systems engineer, trainer, and consultant in
the software infrastructure space. He is passionate about open source and its capacity to help teams
innovate. Nicholas holds a B.S. in chemical engineering from the University of Pittsburgh. He lives
in Nashville, Tennessee, with his Labrador Retriever.
Chris Timberlake is a senior solutions architect at GitLab, where he works closely with the product,
services, and sales teams. Previously, he worked at Red Hat as a senior consultant and owned and
managed a digital marketing firm, and he has a background in security and law enforcement. Chris loves
technical engineering problems and does whatever possible to ensure successful customer outcomes.
Chris is passionate about open source software, collaborative development, and education. He lives
in Chattanooga, Tennessee, with his family.
About the reviewers
Jean-Philippe Baconnais has been a developer for more than 15 years. Initially focused on Java, he later
learned new languages such as Go, as well as about frontend frameworks such as Vue.js and Angular.
Curious by nature, he enjoys learning about and trying out new technologies, applying them, and
sharing them, whether in his own company, Zenika, in communities as a speaker at conferences, or at
local events in his home city of Nantes, France. As an open source developer, he has had the pleasure
of participating in two open source communities and has been given the recognition of GitLab Hero
and GitPod Community Hero.
Philippe Charrière is a customer success engineer at GitLab (having worked there for the last 5 years).
He started working in computer science in 1995 and has held positions as a developer, architect,
project manager, manager, bid manager, customer success manager, solution engineer, strategic account
leader, and customer success engineer. Today, his favorite subject is WebAssembly, particularly with
Go, TinyGo, and Rust.
Table of Contents
Preface xv
Part 1 Getting Started with DevOps, Git, and
GitLab
1
Understanding Life Before DevOps 3
Introducing the Hats for Cats web app 4 Manual security testing summary 15
Building and verifying code manually 4 Packaging and deploying code
Building code manually 4 manually 16
Verifying code manually 5 License compliance scanning 17
More challenges of verifying code 11 Deploying software 17
Security-testing code manually 12 Problems with manual software
Static code analysis 12 development life cycle practices 18
Secret detection 13 Solving problems with DevOps 21
Dynamic analysis 14
How GitLab implements DevOps 22
Dependency scanning 14
Summary 23
Container scanning 15
2
Practicing Basic Git Commands 25
Technical requirements 26 Why Git is popular 30
Why use Git? 27 Drawbacks of Git 32
What is a version control system? 27 Committing code to keep it safe 33
What problems does a VCS solve? 28 Excluding files from a repository 37
viii Table of Contents
Tagging commits to identify versions The “golden” repository 47
of code 39 Configuring remote repositories 48
Branching code for developing in an Pushing 51
isolated space 40 Fetching 51
Git commands for managing branches 43 Pulling 52
Handling merge conflicts 44 Additional resources for learning Git 53
Syncing local and remote copies of Summary 54
repositories 47
3
Understanding GitLab Components 55
Technical requirements 56 Labels 67
Emphasizing the “why” over Issue workflows 68
the “how” 56
Editing files safely with commits,
Introducing the GitLab platform 57 branches, and merge requests 69
What is GitLab? 57 Commit history 73
What problem does GitLab solve? 57 Merging one Git branch into another 74
The verify, secure, and release stages 59 The three amigos – issues, branches, and
merge requests 78
Organizing work into projects
When two amigos are enough 79
and groups 60
How are issues and merge requests different? 79
Example – organizing your Hats for Cats work 63
Enabling DevOps practices with
Tracking work with issues 64
GitLab flow 80
The structure of a GitLab issue 65
Summary 82
The kinds of tasks that issues can represent 67
4
Understanding GitLab’s CI/CD Pipeline Structure 85
Technical requirements 86 Viewing a list of pipelines 87
Defining the terms pipeline, CI – finding out if your code is good 89
CI, and CD 86 CD – finding out where your code should go
(and putting it there) 90
Understanding what a pipeline is 86
GitLab Runners 93
Defining one pipeline per project 87
Understanding different uses of the term Parts of a pipeline – stages, jobs, and
“pipeline” 87 commands 94
Table of Contents ix
Stages 94 Other types of pipelines 100
Jobs 96 Skipping pipelines 101
Commands 97
Reading GitLab CI/CD pipeline
Fitting the pipeline pieces together 98
statuses 102
Running GitLab CI/CD pipelines 98 Configuring GitLab CI/CD pipelines 103
Branch pipelines 98 Summary 107
Git tag pipelines 100
Part 2 Automating DevOps Stages with GitLab
CI/CD Pipelines
5
Installing and Configuring GitLab Runners 111
Technical requirements 112 Each runner has a defined executor 118
Defining GitLab runners and their Runner tags restrict which runners can pick
up which jobs 122
relationship to CI/CD 112
GitLab Runner is an open source application Installing the Runner agent 122
written in Go 112
Installing GitLab Runner 123
GitLab Runner runs CI/CD jobs specified in
Registering a runner with GitLab 123
.gitlab-ci.yml 112
Considerations regarding the various
The runner architecture and
runner types and executors 129
supported platforms 113
Performance considerations 129
GitLab Runner is supported on most
Security considerations 131
platforms and architectures 114
Monitoring considerations 132
Runners can be specific, group, or shared 115
Summary 135
6
Verifying Your Code 137
Technical requirements 138 Compiling Java with Maven 141
Building code in a CI/CD pipeline 138 Compiling C with Gnu Compiler Collection
(GCC) 143
Compiling Java with javac 138
Storing built code as artifacts 145
