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Strimzi Documentation Contributor Guide

1. Introduction

This guide provides information to assist contributors to the Strimzi documentation.

Strimzi documentation is written in Asciidoc.

Inclusive language

Strimzi is committed to using inclusive and respectful language in its code, web pages, and documentation. Contributions to the documentation, as with code submissions, must not contain problematic terms or phrases.

1.1. Documentation tools

The following tools are needed to build the documentation:


Documentation generation tool


Make build system to build complete documentation


YAML build tool to build documentation using make targets

Additionally, for generating API reference content you also need the following:


Java for building code and generating the API reference


Maven for running the Java build

For most documentation updates, Asciidoctor offers the simplest way to check the build.

1.2. Project layout

Strimzi uses public GitHub repositories to host files. The following repositories contain source documentation files.

strimzi-kafka-operator (GitHub)

Strimzi operators code and related documentation.

strimzi-kafka-bridge (GitHub)

Strimzi Kafka Bridge code and related documentation.

strimzi.github.io (GitHub)

Strimzi web site code and quick start documentation.

1.3. Strimzi operators documentation

The main Strimzi documentation is maintained in the /documentation folder of the Strimzi Operators repository. The documentation folder is split into category folders to manage the content.

The folders contain files related to Strimzi guides and the files that provide the content for one or more of these guides – assemblies and modules. Assemblies, which usually encapsulate a feature or process, bring the related content contained in modules together. An assembly is like a sub-section or chapter in a book. A module contain a procedure, concepts or reference content.

1.3.1. Strimzi Overview guide

The intention of the Strimzi Overview guide is for developing an understanding of Strimzi and Apache Kafka. The guide does not contain any instructions. It provides an overview of the concepts behind Apache Kafka, the Kafka component architecture, and how Strimzi supports Kafka in a Kubernetes cluster. The guide also describes how Strimzi Operators help manage a deployment.

The guide contains high-level outlines of the processes required to deploy, configure, secure and monitor a deployment of Strimzi.

1.3.2. Deploying and Managing Strimzi

The Deploying and Managing Strimzi guide provides instructions on all the options available for deploying, managing and upgrading Strimzi. The guide describes what is deployed, and the order of deployment required to run Apache Kafka in a Kubernetes cluster.

As well as describing the deployment steps, the guide also provides pre- and post-deployment instructions to prepare for and verify a deployment. Additional deployment options described include the steps to introduce metrics.

Examples that show how you might configure components are provided. For example, you might want to modify your deployment and introduce additional features, such as Cruise Control or distributed tracing.

Upgrade instructions are provided for Strimzi and Kafka upgrades.

1.3.3. Strimzi Custom Resource API Reference

The Strimzi Custom Resource API Reference guide describes the configuration properties for custom resources.

The reference guide is built from two files.

Strimzi Custom Resource API Reference files

The con-common-configuration-properties.adoc file contains descriptions of common configuration properties. The content for the documentation/modules/appendix_crds.adoc file is generated directly from descriptions in the Java code.

Java files in the api/ folder are annotated so that the descriptions are picked up in the build.

Java annotations for documentation
import io.strimzi.crdgenerator.annotations.Description;
import io.strimzi.crdgenerator.annotations.DescriptionFile;

The tables in appendix_crds.adoc are built from @Description annotations in the Java files.

Additional information is included by adding:

  1. An @DescriptionFile annotation to the Java file

  2. A corresponding description file (.adoc) in the documentation/api/ folder

  3. An include:DESCRIPTION-FILE-NAME reference to the appendix_crds.adoc

The include:DESCRIPTION-FILE-NAME reference is added automatically by the Maven build, so you do not need to add it manually.

For example, to add additional configuration for the KafkaUserQuotas custom resource:

  1. api/src/main/java/io/strimzi/api/kafka/model/KafkaUserQuotas.java contains:

    • import io.strimzi.crdgenerator.annotations.Description

    • import io.strimzi.crdgenerator.annotations.DescriptionFile

    • @Description("descriptions for individual properties…​");

    • An @DescriptionFile annotation

  2. documentation/api includes the io.strimzi.api.kafka.model.KafkaUserQuotas.adoc file containing the additional configuration description.

    The description file requires the same name as the related Java package.

  3. appendix_crds.adoc contains a reference to include the additional configuration description:

    ### `KafkaUserQuotas` schema reference

If you change anything in the api module of the Java code, you must rebuild the Strimzi Custom Resource API Reference using a make command.

1.4. Kafka Bridge documentation

The Kafka Bridge documentation shows how to get started using the Kafka Bridge to make HTTP requests to a Kafka cluster.

The Kafka Bridge documentation is maintained in the Strimzi Kafka Bridge project in GitHub. For information on contributing to the Kafka Bridge documentation, see the readme in the Strimzi Kafka Bridge project.

1.5. Quick start documentation

Strimzi quick starts provide instructions for evaluating Strimzi using Minikube, Kubernetes kind, or Docker Desktop. Steps describe how to deploy and run Strimzi as quickly as possible, with minimal configuration.

The quick starts are maintained in the Strimzi website project in GitHub. For information on contributing to the quick starts, see the readme in the Strimzi website project.

2. Contributing to the documentation

This section shows you how to contribute to the Strimzi documentation and contains important guidelines for creating accessible content.

2.1. Getting started

Before you begin you need to:

2.2. Accessibility guidelines

Strimzi aims to make its content accessible. When contributing to the documentation, ensure that your content adheres to the following guidelines:

  • Images:

    • Include a caption

    • Provide alternative text

    • Are described in the surrounding text

  • Images of text are not used (such as with code fragments)

  • Links provide descriptive text about the target (not click here)

  • Tables:

    • Include a caption

    • Contain headings

    • Provide a logical reading order

    • Don’t contain empty cells

  • Color is not used as the only visual means to convey information (not check the green text)

Example image caption and description
.Operators within the Strimzi architecture
image:operators.png[Operators within the Strimzi architecture]
Example table headings
.File connectors

|File Connector

|Transfers data to your Kafka cluster from a file (the source).

2.3. Adding or updating content

Once you have your local repository set up and have up-to-date copies of upstream content, follow these steps to contribute to the documentation.

You add content to the documentation hosted on GitHub using pull requests (PRs).

Reviewers might be assigned to the PR depending on the changes. A review from a Subject Matter Expert (SME) will check the technical aspects of the content. The PR might not require an SME review if you’re only fixing a typo or broken link.

  1. Open your terminal

  2. cd to the directory where your documentation resides

  3. Checkout the main branch

    $ git checkout main
  4. Update your local repository and fork with the upstream content

    $ git pull upstream main
    $ git push origin main --force
  5. Create a new branch for your work (using the issue number is helpful)

    $ git checkout -b <branch-name>
  6. Make your edits in the editor of your choice

  7. Save your changes locally

  8. Build your documentation to verify that there are no build errors and that everything looks right

    1. This can be done with the Make tooling

  9. If you are creating new files, add the files to the repository

    $ git status
    $ git add <file-name>
  10. Commit your changes

    $ git commit -a -s -m "<message>"

    Note that the project requires all commits to be signed off, indicating that you certify the changes with the developer certificate of origin (DCO).

  11. Push your changes to your fork

    $ git push origin HEAD
  12. If the update is rejected because the commit is behind, merge your changes

    $ git pull upstream main
    $ git push -f origin HEAD
  13. Visit your fork on GitHub

  14. Click Compare & pull request

3. AsciiDoc format reference

Tips for which AsciiDoc markup to use when formatting text.

Monospace (`)
Item Example

File names and paths

The `/home/user/.bashrc` file …​

Literal values

If the value is `true` …​

Configuration attributes

Set the `enabled` attribute …​

Java class names

The `java.sql.Connection` class …​

Java annotations

The `@Clustered` annotation …​

Italics (_)
Item Example

Guide titles

See the _Installation Guide_ …​

Emphasis for a term (only emphasize first time)

_High availability_ refers to the …​

Bold (*)
Item Example

GUI items (menus, buttons)

Click the *Add* button and …​

Underline (value)
Item Example

Default item in a multi-select


4. Style guidelines

4.1. Adding code and configuration examples

The Strimzi documentation contains many code and configuration examples. Examples are a useful way of demonstrating a process.

If you want to add example code and configuration to your contribution, use the following format in an asciidoc code block.

Configuration example
[source,yaml,subs="+quotes,attributes"] (1)
apiVersion: {KafkaApiVersion}
kind: Kafka
  name: my-cluster
    replicas: 3 # <1> (2)
    # ... (3)
  1. Syntax for the example. Here the source language is yaml. Use subs to apply attribute (attributes) and formatting (subs). In this example, kafka.strimzi.io/v1beta2 is substituted with an attribute value specified in the /shared/attributes.adoc file. If quotes is specified in subs, asciidoc formatting is applied to the code block. Here, bold is applied to the 3 value of replicas. If quotes isn’t used, asciidoc formatting is ignored in the code block.

  2. Add callouts to describe a line of code or configuration. Use a hash (#) before the callout number so that the example is copy-friendly.

  3. Use a hash and ellipsis (# …​) to show that part of the code or configuration has been omitted.

4.2. Styling headings and titles

Uses sentence-case headings for modules, tables, and figures. For example, Secrets generated by the operators not Secrets Generated By The Operators.

4.3. Section IDs

Each file in the documentation requires an ID. The ID takes the form [id="name-of-file-{context}"].

4.4. User-replaced values

Style user-replaced values (replaceables) with angle brackets (< >). Use underscores ( _ ) for multi-word values. If you are referencing code or commands, also use monospace.

Table 1. User-replaced values quick reference
Value Shows as





If adding a user-replaced value within a source code block, add subs="+quotes" to the source tag for it to render. (For example : [source,shell,subs="+quotes"]).

Refer links to the top-level sections of books as chapters, not sections or topics.

Table 2. Links Quick Reference
Link type Use

External links


Internal links

xref:doc_id[Section Title]

If you use the caret syntax (^) more than once in a single paragraph, you may need to escape the first occurrence with a backslash.

4.6. Adding images

Add images for screenshots, diagrams and so on in the following format:

Adding an image
.Title of image

You can also add inline images, such as in steps for procedures:

Adding an inline image to a step
. My step.
.My inline image.

5. Building the documentation locally

When you make changes to the documentation, it is a good practice to do a local test build to verify the book builds successfully and renders as you expect before you submit the merge request back to upstream main.

After you have made documentation updates in your local GitHub clone of the strimzi-kafka-operator project, you can build the documentation using AsciiDoctor or the Makefile provided with the project.

5.1. Building documentation using AsciiDoctor

As the documentation is based on asciidoc, you can use AsciiDoctor to build the guides locally. To build a guide using AsciiDoctor on your local machine, you run the asciidoctor command for the source file of the guide.

For example, this command builds the Overview:

asciidoctor <path_to_overview.adoc>

5.2. Building documentation with make commands

Use make commands from the root of the strimzi-kafka-operator project to build all the documentation at the same time. The documentation is output to documentation/html.

make docu_clean

Deletes all temporary files

make docu_check

Executes the documentation checks in .azure/scripts/check_docs.sh

make docu_html

Generates HTML versions of all the guides

make docu_htmlnoheader

Generates HTML versions of all the guides without the HTML headers so they are suitable for including in a website

Before running the make commands, ensure that you remove any old build files from the documentation directories. Failure to do so will result in these files being included in the documentation checks and causing build failures. For instance, if you previously generated an HTML file in the deploying directory using Asciidoctor, make sure to delete that file.

5.3. Generating the Strimzi Custom Resource API Reference

The documentation/modules/appendix_crds.adoc file provides the main content for the Strimzi Custom Resource API Reference. It is generated directly from the Java code when building the operators.

If you change the Strimzi API, you need to regenerate the API Reference before submitting your PR by running the following from the root:

mvn clean -DskipTests install
make crd_install

The build uses yq, so make sure it is kept up-to-date for it to work properly.

You only have to generate the Strimzi Custom Resource API Reference if you changed anything in the api module of the Java code.

Appendix A: Files and attributes

A.1. Important files

Standard attributes


Shared includes




A.2. Anchor names and file names

To optimize modular documentation, follow these guidelines for naming module anchors and files:

Anchor names

Provide an anchor in the format [id='anchor-name'] for every module so that it can be identified by Asciidoctor when reused or cross-referenced. Give the anchor the same or similar name as the module heading, separated by dashes:

= Module Heading

First sentence of topic.
Note on other anchor formats (Not Recommended)

The format defined here is recommended because it is the most stable and versatile of anchor formats, and supports variables that enable topics to be reused and cross-referenced properly. Other anchor formats include [[anchor-name]] and [#anchor-name], but these formats either do not support variables for content reuse or do not support certain character types, such as periods. These limitations cause errors at build time.

File names

Name the module file using the same name as the anchor used in it, which should also align with or resemble the module heading. Separate these elements with dashes. Add a prefix with an underscore to the file name to indicate the module type in the format prefix-file-name. Use snip- for a snippet, con- for concept, ref- for reference, proc- for procedure, assembly- for assembly, and image- for images and screenshots.

  • snip-guided-decision-urls.adoc (Snippet of reusable content)

  • con-guided-decision-tables.adoc (Concept module)

  • proc-creating-guided-decision-tables.adoc (Procedure module for creating)

  • proc-editing-guided-decision-tables.adoc (Procedure module for editing)

  • ref-guided-decision-table-examples.adoc (Reference module with examples)

  • ref-guided-decision-table-columns.adoc (Reference module with column types)

  • assembly-guided-decision-tables.adoc (Assembly of guided decision table modules)

  • image-guided-decision-example.adoc (Screenshot or image of guided decision table modules)

Appendix B: Setting up git

This section explains how to set up your system to connect to the proper git repositories.

B.1. Install git

If using Fedora, open your terminal and enter the proper installation command.


$ yum install git (up to Fedora 21)
$ dnf install git (Fedora 22 and later)

Other operating systems

B.2. Configuring git

Once you have git installed you’ll want to set up your git account.

  1. Open Terminal

  2. Set your name and email

    $ git config --global user.name "<your-name>"
    $ git config --global user.email "<your-email>"
    The email you specify should be the same one found in your email settings. To keep your email address hidden, see Keeping your email address private.
  3. Set your git defaults

    $ git config --global pull.rebase true
    $ git config --global push.default simple

B.3. Fork the upstream (GitHub) repository

Fork the strimzi-kafka-operator upstream repository to create a copy under your own GitHub ID. This allows you to work on multiple features and push changes to branches in your own GitHub instance so that you do not have to worry about losing work. When you are ready, you can request the changes to be merged back into the upstream repository.

  1. Open a browser and navigate to the upstream repository located at https://github.com/strimzi/strimzi-kafka-operator

  2. Click Fork located in the upper right under your profile icon.

  3. Select your user account for the location of the forked repository. This creates your own copy of the repository under your own GitHub ID.

B.4. Add your SSH keys to GitHub

If you choose to use the SSH address for your clones, you will need to add an SSH Key to GitHub first.

  1. Open Terminal.

  2. Check to see if you have a public SSH key:

    $ ls ~/.ssh/
  3. If you don’t have a key, generate one:

    $ ssh-keygen -t rsa -C "<your-email>"
  4. Open your key in an editor:

    $ cd ~/.ssh/
    $ vi id_rsa.pub
  5. Copy the contents of the file to your clipboard.

  6. Visit https://github.com/settings/keys

  7. Click New SSH Key.

  8. Give your key a name and paste the contents of your key file.

  9. Click Add SSH Key.

B.5. Clone your forked upstream repository

Clone your forked repository to bring your GitHub repository files to your local machine. Your forked repository is now the origin repository for your local files.

For more information about forking and cloning, consult the official GitHub documentation.

Using SSH

  1. Open Terminal.

  2. Navigate to the directory where you want to create the new repository folder.

  3. Type the following command:

    $ git clone git@github.com:<username>/strimzi-kafka-operator.git
  4. Navigate to the newly created strimzi-kafka-operator folder.

    $ cd strimzi-kafka-operator/


While there are fewer steps in this option, you have to enter your GitHub credentials with every change you make.

  1. Open Terminal.

  2. Navigate to the directory where you want to create the new repository folder.

  3. Type the following command:

    $ git clone https://github.com/<username>/strimzi-kafka-operator.git
  4. Enter your GitHub credentials to complete the clone.

  5. Navigate to the newly created strimzi-kafka-operator folder.

    $ cd strimzi-kafka-operator/

B.6. Add the upstream as a remote repository

Once you have your fork checked out and cloned locally, add the downstream repository as a remote.

Using SSH

  1. List the current remote repositories:

    $ git remote -v
    origin	git@github.com:<username>/strimzi-kafka-operator.git (fetch)
    origin	git@github.com:<username>/strimzi-kafka-operator.git (push)
  2. Add the upstream as a remote repository and fetch its contents. This allows you to check out and work with the latest source code.

    $ git remote add -f upstream  git@github.com:strimzi/strimzi-kafka-operator.git
  3. Enter your GitHub credentials to complete the remote add process.

  4. Verify the new remote was added:

    $ git remote -v
    origin	git@github.com:<username>/strimzi-kafka-operator.git (fetch)
    origin	git@github.com:<username>/strimzi-kafka-operator.git (push)
    upstream	git@github.com:strimzi/strimzi-kafka-operator.git (fetch)
    upstream	git@github.com:strimzi/strimzi-kafka-operator.git (push)


  1. List the current remote repositories:

    $ git remote -v
    origin	https://github.com/<username>/strimzi-kafka-operator.git (fetch)
    origin	https://github.com/<username>/strimzi-kafka-operator.git (push)
  2. Add the upstream as a remote repository and fetch its contents. This allows you to check out and work with the latest source code.

    $ git remote add -f upstream  https://github.com/strimzi/strimzi-kafka-operator.git
  3. Enter your GitHub credentials to complete the remote add process.

  4. Verify the new remote was added:

    $ git remote -v
    origin	https://github.com/<username>/strimzi-kafka-operator.git (fetch)
    origin	https://github.com/<username>/strimzi-kafka-operator.git (push)
    upstream	https://github.com/strimzi/strimzi-kafka-operator.git (fetch)
    upstream	https://github.com/strimzi/strimzi-kafka-operator.git (push)

B.7. Updating repository URLs

If the upstream repository is moved, you can change the downstream URL by using the following command:

$ git remote set-url upstream https://github.com/strimzi/strimzi-kafka-operator.git

Use the following command any time you need to fetch the latest source code locally:

$ git fetch upstream

Appendix C: Git tips

C.1. Delete branches

To delete all of your branches except the branch you are on:

$ git checkout main
$ for br in `git branch` ; do git branch -D $br ; done

To delete one branch:

$ git checkout main
$ git branch -D <branch-name>

C.2. Resolve conflicts

To resolve a merge conflict in an existing pull request:

$ git checkout <branch-name>
$ git branch -u origin <branch-name>
$ git pull --rebase upstream main
$ git push -f origin HEAD

C.3. Reset your fork

If your fork is both ahead of and behind the origin you can reset your fork to match the origin and start with a clean slate.

$ git checkout main
$ git reset --hard upstream/main
$ git push origin main --force
$ git pull upstream main
$ git push origin main --force

C.4. Using ssh-agent to save your SSH key’s passphrase

If you have to enter your SSH key’s passphrase whenever working with the repository from the command line, you might want to use the ssh-agent to remember the passphrase for you.

Before using the ssh-agent you will see a prompt to enter your passphrase after each git command.

[amq-repo]$ git pull --rebase upstream main
Enter passphrase for key '/home/<username>/.ssh/id_rsa':

To add your passphrase to the ssh-agent:

[amq-repo]$ ssh-add
Enter passphrase for /home/<username>/.ssh/id_rsa:

After entering your passphrase you will see confirmation that your passphrase has been saved:

Identity added: /home/<username>/.ssh/id_rsa (/home/<username>/.ssh/id_rsa)

C.5. Access another writer’s unmerged commits

This is the process you can use if you need commits another writer has submitted in a merge request that is not yet merged.

  1. Check out a new topic branch from upstream/main as you normally do.

    $ git fetch upstream
    $ git checkout -b <new-topic-branch> upstream/main
  2. If you have not yet added that writer’s remote repository, add it now.

    $ git remote add -f <user> git@github.com:<user>/strimzi-kafka-operator.git
  3. Rebase to bring in the changes that are in that user’s outstanding origin/<merge-request-branch> branch.

    $ git rebase <user>/<merge-request-branch>

    (you’ll see the following response)

    First, rewinding head to replay your work on top of it...
    Fast-forwarded <new-topic-branch> to <user>/<merge-request-branch>

Revised on 2024-04-16 23:18:44 UTC