Documentation guidelines

The documentation guidelines for OpenShift 4 build on top of the Red Hat modular docs reference guide.

Note

These Documentation guidelines are primarily concerned with the modular structure and AsciiDoc / AsciiBinder requirements for building OpenShift documention. For general style guidelines in OpenShift docs, see the following:

Primary source: IBM Style
Supplementary source: Red Hat supplementary style guide for product documentation

When looking for style guidance, reference the Red Hat supplementary style guide for product documentation first, because it overrides certain guidance from the IBM Style guide.

General file guidelines

Set your editor to strip trailing whitespace.
Do not hard wrap lines at 80 characters (or at any other length).

It is not necessary to update existing content to unwrap lines, but you can remove existing hard wrapping from any lines that you are currently working in.

Tip

In the Pulsar editor, you can use Ctrl+J to undo hard wrapping on a paragraph.

Assembly file metadata

Every assembly file should contain the following metadata at the top, with no line spacing in between, except where noted:

:_mod-docs-content-type: ASSEMBLY                                        (1)
[id="<unique-heading-for-assembly>"]                            (2)
= Assembly title                                                (3)
include::_attributes/common-attributes.adoc[]                   (4)
:context: <unique-context-for-assembly>                         (5)
                                                                (6)
toc::[]                                                         (7)

The content type for the file. For assemblies, always use :_mod-docs-content-type: ASSEMBLY. Place this attribute before the anchor ID or, if present, the conditional that contains the anchor ID.
A unique (within OpenShift docs) anchor ID for this assembly. Use lowercase. Example: cli-developer-commands
Human readable title (notice the = top-level header)

Includes attributes common to OpenShift docs.

Note

The {product-title} and {product-version} common attributes are not defined in the _attributes/common-attributes.adoc file. Those attributes are pulled by AsciiBinder from the distro mapping definitions in the _distro_map.yml file. See Product title and version and attribute files for more information on this topic.
If you use a variable in the title of the first assembly in a section, move the include attributes directive above the title in this assembly. Otherwise, the variable will not render correctly on access.redhat.com.

Context used for identifying headers in modules that is the same as the anchor ID. Example: cli-developer-commands.
A blank line. You must have a blank line here before the toc.
The table of contents for the current assembly.

Note

Do not use backticks or other markup in assembly or module headings. You can use backticks or other markup in the title for a block, such as a code block .Example or a table .Description title.
Do not use "Optional:" to prefix a heading title. According to IBM Style, this practice is reserved for optional steps and code callouts. With content reuse and modular documentation, you cannot be certain that all future use of a module will remain optional. For more information, see "Indicating optional and conditional steps (Requires IBM Style login)".

After the heading block and a single whitespace line, you can include any content for this assembly.

Note

The assembly title, which is the first line of the document, is the only level 1 ( = ) title. Section headers within the assembly must be level 2 ( == ) or lower. When you include modules, you must add leveloffsets in the include statements. You can manually add more level 2 or lower section headers in the assembly.

Module file metadata

Every module should be placed in the modules folder and should contain the following metadata at the top:

// Module included in the following assemblies:
//
// * list of assemblies where this module is included              (1)

:_mod-docs-content-type: <TYPE>                                    (2)
[id="<module-anchor>_{context}"]                                   (3)
= Module title                                                     (4)

List of assemblies in which this module is included.
The content type for the file. Replace <TYPE> with the actual type of the module, CONCEPT, REFERENCE, or PROCEDURE. Place this attribute before the anchor ID or, if present, the conditional that contains the anchor ID.
A module anchor with {context} that must be lowercase and must match the module’s file name.
Human readable title. To ensure consistency in the results of the leveloffset values in include statements, you must use a level one heading ( = ) for the module title.

Example:

// Module included in the following assemblies:
//
// * cli_reference/openshift_cli/developer-cli-commands.adoc

:_mod-docs-content-type: REFERENCE
[id="cli-basic-commands_{context}"]
= Basic CLI commands

Note	Do not use backticks or other markup in assembly or module headings. You can use backticks or other markup in the title for a block, such as a code block `.Example` or a table `.Description` title.

Text snippet file metadata

Every text snippet should be placed in the snippets/ folder and should contain the following metadata at the top:

// Text snippet included in the following assemblies: (1)
//
// * list of assemblies where this text snippet is included
//
// Text snippet included in the following modules:    (2)
//
// * list of modules where this text snippet is included

:_mod-docs-content-type: SNIPPET                               (3)

List of assemblies in which this text snippet is included.
List of modules in which this text snippet is included.
The content type for the file. For snippets, always use :_mod-docs-content-type: SNIPPET. Place this attribute before the anchor ID, the conditional that contains the anchor ID, or the first line of body text.

Note	An anchor ID and human readable title are not required metadata. This type of component is text only and not intended to be published or cross referenced on its own. See Writing text snippets.

Example:

// Text snippet included in the following assemblies:
//
// * installing/installing_aws/ipi/installing-aws-default.adoc
// * installing/installing_azure/installing-azure-default.adoc
// * installing/installing_gcp/installing-gcp-default.adoc

:_mod-docs-content-type: SNIPPET
In {product-title} version {product-version}, you can install a cluster on {cloud-provider-first} ({cloud-provider}) that uses the default configuration options.

Content type attributes

Each .adoc file must contain a :_mod-docs-content-type: attribute in its metadata that indicates its file type. This information is used by some publication processes to sort and label files.

Add the attribute from the following list that corresponds to your file type:

:_mod-docs-content-type: ASSEMBLY
:_mod-docs-content-type: CONCEPT
:_mod-docs-content-type: PROCEDURE
:_mod-docs-content-type: REFERENCE
:_mod-docs-content-type: SNIPPET

Place the attribute in the file metadata. The following list describes the best attribute placement options:

Directly before the first anchor ID in a file
If the first anchor ID is enclosed in a conditional, before the conditional
Between the list of assemblies in which this module is included and the first line of body text

The metadata examples contain sample placement for each file type, assembly, module, and snippet.

Attribute files

All attribute files must be placed in the _attributes directory. In most cases involving OpenShift Container Platform or OKD, add attributes to the common-attributes.adoc file instead of creating or using a separate attributes file. Before you add an attribute, review the contents of the common-attributes.adoc file to ensure that it is not already defined.

Important

If you think that you need a separate attributes file, check with the docs team before you create it.

It is acceptable to group related attributes in the common-attributes.adoc file under a comment, as shown in the following example:

//gitops
:gitops-title: Red Hat OpenShift GitOps
:gitops-shortname: GitOps

It is also acceptable to enclose attributes in a distro-based conditional, but you must place attribute definitions for the openshift-enterprise distro first. The following example shows how to set a different value for the :op-system-base: attribute for OKD:

:op-system-base: RHEL

Note	When backporting content that contains IBM-related attributes to `enterprise-4.13` and earlier branches, you might need to create manual cherry picks because IBM-related attributes names are not consistent with later release branches.

Assembly/module file names

Try to shorten the file name as much as possible without abbreviating important terms that may cause confusion. For example, the managing-authorization-policies.adoc file name would be appropriate for an assembly titled "Managing Authorization Policies".

Directory names

If you create a directory with a multiple-word name, separate each word with an underscore, for example backup_and_restore.

Do not create or rename a top-level directory in the repository and topic map without checking with the docs program manager first.

Avoid creating two levels of subdirectories because the breadcrumb bar on docs.openshift.com breaks. If you have a valid use case for two levels of subdirectories, talk with your DPM/CS (and, for aligned teams, the OpenShift DPM) for approval before creating it.

When creating a new directory or subdirectory, you must create four symbolic links in it:

An images symbolic link to the top-level images/ directory
A modules symbolic link to the top-level modules/ directory
A snippets symbolic link to the top-level snippets/ directory
An _attributes symbolic link to the top-level _attributes/ directory

If the directory that contains an assembly does not have the images symbolic link, any images in that assembly or its modules will not be included properly when building the docs.

Tip

To create the symbolic links:

Navigate to the directory that you need to add the links in.
Use the following command to create a symbolic link:
```
$ ln -s <target_directory> <link_name>
```
For example, if you are creating the links in a directory that is two levels deep, such as cli_reference/openshift_cli, use the following commands:
```
$ ln -s ../../images/ images
$ ln -s ../../modules/ modules
$ ln -s ../../snippets/ snippets
$ ln -s ../../_attributes/ _attributes
```
Be sure to adjust the number of levels to back up (../) depending on how deep your directory is.

If you accidentally create an incorrect link, you can remove that link by using unlink <link_name>.

Assembly/Module titles and section headings

Use sentence case in all titles and section headings. See http://www.titlecase.com/ or https://convertcase.net/ for a conversion tool.

Try to be as descriptive as possible with the title or section headings without making them unnecessarily long. For assemblies and task modules, use a gerund form in headings, such as:

Creating
Managing
Using

Do not use "Overview" as a heading.

Do not use backticks or other markup in assembly or module headings.

Do not use special characters or symbols in titles. Symbols and special characters in titles can cause rendering errors in the HTML output.

Use only one level 1 heading (=) in any file.

Discrete headings

If you have a section heading that you do not want to appear in the TOC (like if you think that some section is not worth showing up or if there are already too many nested levels), you can use a discrete (or floating) heading:

https://docs.asciidoctor.org/asciidoc/latest/blocks/discrete-headings/

A discrete heading also will not get a section number in the Customer Portal build of the doc. Previously, we would use plain bold mark-up around a heading like this, but discrete headings also allow you to ignore section nesting rules (like jumping from a == section level to a ==== level if you wanted for some style reason).

To use a discrete heading, just add [discrete] to the line before your unique ID. For example:

[discrete]
[id="managing-authorization-policies_{context}"]
== Managing authorization policies

Anchoring titles and section headings

All titles and section headings must have an anchor ID. The anchor ID must be similar to the title or section heading.

Anchoring in assembly files

The following is an example anchor ID in an assembly file:

[id="configuring-alert-notifications"]
= Configuring alert notifications

Note	Do not include line spaces between the anchor ID and the section title.

Anchoring in module files

You must add the {context} variable to the end of each anchor ID in module files. When called, the {context} variable is resolved into the value declared in the :context: attribute in the corresponding assembly file. This enables cross-referencing to module IDs in context to a specific assembly and is useful when a module is included in multiple assemblies.

Note	The `{context}` variable must be preceded by an underscore (`_`) when declared in an anchor ID.

The following is an example of an anchor ID for a module file title:

[id="sending-notifications-to-external-systems_{context}"]
= Sending notifications to external systems

The following is an example of an anchor ID for a second level (==) heading:

[id="deployment-scaling-benefits_{context}"]
== Deployment and scaling benefits

Anchoring "Prerequisites", "Additional resources", and "Next steps" titles in assemblies

Use unique IDs for "Prerequisites", "Additional resources", and "Next steps" titles in assemblies. You can add the prefixes prerequisites_, additional-resources_, or next-steps_ to a unique string that describes the assembly topic. The unique string can match the value assigned to the :context: attribute in the assembly.

Note	The `prerequisites_`, `additional-resources_`, and `next-steps_` prefixes must end with an underscore (`_`) when declared in an anchor ID in an assembly.

The following examples include IDs that are unique to the "Configuring alert notifications" assembly:

Example unique ID for a "Prerequisites" title

[id="prerequisites_configuring-alert-notifications"]
== Prerequisites

Example unique ID for an "Additional resources" title

[role="_additional-resources"]
[id="additional-resources_configuring-alert-notifications"]
== Additional resources

Example unique ID for a "Next steps" title

[id="next-steps_configuring-alert-notifications"]
== Next steps

Writing assemblies

An assembly is a collection of modules that describes how to accomplish a user story. Module content is added to an assembly using the include directive. The include directive includes contents from another file in the current document. Files can be modules or snippets formatted in AsciiDoc, or another text format such as YAML.

An include directive must always be on its own line.

Standard module include syntax

include::modules/module-filename.adoc[leveloffset=+1] (1)

[leveloffset=] is relative, and changes the header level of included content.

You can use tag attributes to define regions of a file and include by tag instead of the whole file. This enables you to make conditional modifications to existing modules instead of duplicating content. When creating a tag, use a tag name that makes it easy to understand where the content defined will be included.

Example 1. Tagged module include syntax

include::modules/module-with-tags-filename.adoc[leveloffset=+1,tag=TagName]

You can filter out the regions defined by a tag attribute by using expressions in place of or in conjunction with the tag name. If you add tag defined conditional content to a module with no existing tags, you must update existing includes of the file you are changing to exclude your content.

Important

Including lines by content ranges can lead to content errors when the included file is subsequently updated and is not permitted.

Avoid nesting assemblies in other assembly files. You can create more complicated document structures by modifying the topic maps.

For more information about forming assemblies, see the Red Hat modular docs reference guide and the assembly template.

Note

When using the "Prerequisites", "Next steps", or "Additional resources" headings in an assembly, use == formatting, such as == Prerequisites or == Additional resources. Use of this heading syntax at the assembly level indicates that the sections relate to the whole assembly.

Only use . formatting (.Additional resources) to follow a module in an assembly. Because you cannot use the xrefs in modules, this functions as a trailing include at the assembly level, where the . formatting of the include statement indicates that the resource applies specifically to the module and not to the assembly.

Writing concepts

A concept contains information to support the tasks that users want to do and must not include task information like commands or numbered steps. In most cases, create your concepts as individual modules and include them in appropriate assemblies.

Avoid using gerunds in concept titles. "About <concept>" is a common concept module title.

For more information about creating concept modules, see the Red Hat modular docs reference guide and the concept template.

Writing procedures

A procedure contains the steps that users follow to complete a single process or task. Procedures contain ordered steps and explicit commands. In most cases, create your procedures as individual modules and include them in appropriate assemblies.

Use a gerund in the procedure title, such as "Creating".

For more information about writing procedures, see the Red Hat modular docs reference guide and the procedure template.

Note

When needed, use .Prerequisites, .Next steps, or .Additional resources syntax to suppress TOC formatting within a module. Do not use == syntax for these headings in modules. Because you cannot use the xrefs in modules, if you need to include a link under one of these headings, place the entire subsection in the assembly instead.

Writing text snippets

A text snippet is an optional component that lets you reuse content in multiple modules and assemblies. Text snippets are not a substitute for modules but instead are a more granular form of content reuse. While a module is content that a reader can understand on its own (like an article) or as part of a larger body of work (like an assembly), a text snippet is not self-contained and is not intended to be published or cross referenced on its own.

In the context of modules and assemblies, text snippets do not include headings or anchor IDs. Text snippets also cannot contain xrefs. This type of component is text only. Examples include the following:

Admonitions that appear in multiple modules.
An introductory paragraph that appears in multiple assemblies.
The same series of steps that appear in multiple procedure modules.
A deprecation statement that appears in multiple sets of release notes.

Example:

You could write the following paragraph once and include it in each assembly that explains how to install a cluster using the installer-provisioned default values:

In {product-title} version {product-version}, you can install a cluster on {cloud-provider-first} ({cloud-provider}) that uses the default configuration options.

Note

In the example, cloud-provider-first and cloud-provider are not defined by the common-attributes module. If you use an attribute that is not common to OpenShift docs, make sure to define it locally in either the assembly or module, depending on where the text snippet is included. Because of this, consider adding all attributes that you add to snippets to the common-attributes.adoc file.

For more information about creating text snippets, see the Red Hat modular docs reference guide.

Auto-generated content

The following content is auto-generated in each release and must not be manually edited:

The OpenShift CLI (oc) command references modules/oc-by-example-content.adoc and modules/oc-adm-by-example-content.adoc.
The following API references content in the rest_api folder: the contents of all <topic>_apis subfolders and the rest_api/objects/index.adoc and rest_api/index.adoc assemblies.
OpenShift Virtualization runbook modules: modules/virt-runbook-<runbook>.adoc.

Note

If the content in these files needs to be updated, the update must be made in the applicable code repository where these files are generated from. The updates are reflected when the files are generated the next time, for example a future release. For help with where to make the updates, you can contact Andrea Hoffer for the CLI docs, Jason Boxman for the API docs, or Avital Pinnick for the OpenShift Virtualization runbooks.

Using conscious language

To assist with the removal of the problematic word "master" from the documentation, use the following terminology when referring to OpenShift control plane nodes:

Branch	Control plane node reference
`main`, `enterprise-4.9`, and later enterprise versions	Control plane node
`enterprise-4.8` and earlier enterprise versions	Control plane (also known as master) node
`enterprise-3.11`	Master node

You can replace "node" in the preceding examples with "machine", "host", or another suitable description.

In general text, use the term "control plane machine" in place of "master machine"; use the term "compute machine" in place of "worker machine". Be mindful of certain valid code entities, such as master role, worker role, and infra role.

Note	If you are cherry picking from `main` to `enterprise-4.8` or earlier, you must manually cherry pick to include the “(also known as master)” phrasing. This is required only if the phrase “control plane” is introduced for the first time in an assembly or module.

Adding a subsection on making open source more inclusive

If you create a release notes assembly for a sub-product within the openshift/openshift-docs repo, you might include a "Making open source more inclusive" statement. Instead of pasting the statement from the OpenShift Release Notes, use the following module, which is available in the enterprise-4.8 branch and later:

include::modules/making-open-source-more-inclusive.adoc[leveloffset=+1]

Product title and version

When possible, generalize references to the product name and/or version by using the {product-title} and/or {product-version} attributes. These attributes are pulled by AsciiBinder from the OpenShift distribution, or distro, mapping definitions in the _distro_map.yml file.

The {product-title} comes from the first name: field in a distro mapping, while the associated {product-version} comes from the name: fields on any branches: defined.

How these attributes render is dependent on which distro and branch build you are viewing. The following table shows the current distros and the possible values for {product-title} and {product-version}, depending on the branch:

Distro	`{product-title}`	`{product-version}`
`openshift-origin`	OKD	3.6, 3.7, 3.9, 3.10, 3.11 4.8, 4.9, 4.10, 4.11, 4.12, 4.13, 4.14, 4.15 4 for the `latest/` build from the `main` branch
`openshift-enterprise`	OpenShift Container Platform	3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.9, 3.10, 3.11 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 4.10, 4.11, 4.12, 4.13, 4.14, 4.15, 4.16
`openshift-dedicated`	OpenShift Dedicated	No value set for the latest `dedicated/` build from the `enterprise-4.15` branch 3 for the `dedicated/3` build from the `enterprise-3.11` branch
`openshift-rosa`	Red Hat OpenShift Service on AWS	No value set for the `rosa/` build from the `enterprise-4.15` branch
`openshift-online`	OpenShift Online	Pro

For example:

You can deploy applications on {product-title}.

This is a safe statement that could appear in probably any of the builds, so an ifdef/endif statement is not necessary. For example, if you were viewing a build for the openshift-enterprise distro (for any of the distro-defined branches), this would render as:

You can deploy applications on OpenShift Container Platform.

And for the openshift-origin distro:

You can deploy applications on OKD.

Considering that we use distinct branches to keep content for product versions separated, global use of {product-version} across all branches is probably less useful, but it is available if you come across a requirement for it. Just consider how it will render across any branches that the content appears in.

If it makes more sense in context to refer to the major version of the product instead of a specific minor version (for example, if comparing how something in OpenShift Container Platform 4 differs from OpenShift Container Platform 3), just use the major version number. Do not prepend with a v, as in v3 or v4.

Note

Other common attribute values are defined in the _attributes/common-attributes.adoc file. Where possible, generalize references to those values by using the common attributes. For example, use {cluster-manager-first} to refer to Red Hat OpenShift Cluster Manager. If you need to add an attribute to the _attributes/common-attributes.adoc file, open a pull request to add it to the attribute list. Do not create a separate attributes file without first consulting the docs team.

Third-party vendor product names

Red Hat integrates with many third-party vendor products. For certain integrated products, third-party vendor staff might have access to certain Red Hat resources and be contactable within Red Hat. On other occasions, common open-source products might be widely used across IT infrastructure providers, so Red Hat might not have direct contacts to organizations that own these products.

Depending on the third-party vendor’s requirements, you might need to add a registered trademark symbol to all of the vendor’s product names or only on the first occurence of referencing the product name in an assembly, a module, or a document.

Choose any of the following sources for clarification on using the symbol for a specific third-party vendor product name:

Visit the third-party vendor’s website and contact them directly.
Contact internal Red Hat product teams or integrated third-party vendor teams.
Contact the Red Hat Legal team. Only consider this option when the other two options did not provide clear context for your query.

Important

Do not use Asciidoctor character replacement substitutions, which rely on a Unicode code point such as ®, to set the registered symbol in an Asciidoc file. Instead use ® beside the product name. For example, IBM® LinuxONE.

Do not apply any superscript, such as ®, or subscript formatting to module or assembly headings.

For more information about contacting the Red Hat’s Legal team, see Copyright Notices and Trademark Legends on the The Source.

Conditional content

You can use ifdef and ifeval statements to control the way content displays in different distributions and assemblies.

Note	You can nest conditional statements that involve distribution and assembly context, but you must ensure that you close the if statements correctly.

Because we maintain separate branches for each OpenShift Container Platform version, do not use if statements that are based on product version to vary content.

Conditionals for distributions

Use ifdef and ifndef statements to control content based on distribution, as described in the previous section. For example, the following example renders differently in (openshift-origin) and OpenShift Container Platform (openshift-enterprise):

ifdef::openshift-origin[]
You can link:https://www.keycloak.org/docs/latest/server_admin/index.html#openshift[configure a Keycloak] server as an OpenID
Connect identity provider for {product-title}.
endif::[]

ifdef::openshift-enterprise[]
You can
link:https://access.redhat.com/documentation/en-us/red_hat_single_sign-on/[configure Red Hat Single Sign-On]
as an OpenID Connect identity provider for {product-title}.
endif::[]

In OKD, this section renders as the following text:

You can configure a Keycloak server as an OpenID Connect identity provider for OKD.

In OpenShift Container Platform, this section renders as the following text:

You can configure Red Hat Single Sign-On as an OpenID Connect identity provider for OpenShift Container Platform.

Conditionals for different assemblies

Use a combination of ifdef and ifeval statements to control content that needs to vary between assemblies. These conditional statements rely on a combination of the context attribute for each assembly and specific temporary attributes within each module to control content.

The following sample shows a simple example. In the assembly that contains the context attribute updating-restricted-network-cluster, an extra paragraph is displayed.

ifeval::["{context}" == "updating-restricted-network-cluster"]
:restricted:
endif::[]

...

ifdef::restricted[]
If you are upgrading a cluster in a restricted network, install the `oc` version that you plan to upgrade to.
endif::restricted[]

...

ifeval::["{context}" == "updating-restricted-network-cluster"]
:!restricted:
endif::[]

Note that you must set and unset each temporary attribute that you introduce to an assembly. Use the temporary attributes in the applicable ifdef and ifndef statements to vary text between the assemblies. The preceeding example uses restricted as the temporary attribute to display an additional paragraph for the assembly with the updating-restricted-network-cluster context attribute.

Node names

Do not use internal company server names in commands or example output. Provide generic OpenShift Container Platform node name examples that are not provider-specific, unless required. Where possible, use the example.com domain name when providing fully qualified domain names (FQDNs).

The following table includes example OpenShift Container Platform 4 node names and their corresponding role types:

Node name	Role type
node-1.example.com	You can use this format for nodes that do not need role-specific node names.
node-2.example.com
node-3.example.com
control-plane-1.example.com	You can use this format if you need to describe the control plane role type within a node name.
control-plane-2.example.com
control-plane-3.example.com
compute-1.example.com	You can use this format if you need to describe the compute node role type within a node name.
compute-2.example.com
bootstrap.example.com	You can use this format if you need to describe the bootstrap node role type within a node name.

This example lists the status of cluster nodes that use the node name formatting guidelines:

[source,terminal]
----
$ oc get nodes
----
+
.Example output
[source,terminal]
----
NAME                          STATUS   ROLES    AGE   VERSION
compute-1.example.com         Ready    worker   33m   v1.19.0+9f84db3
control-plane-1.example.com   Ready    master   41m   v1.19.0+9f84db3
control-plane-2.example.com   Ready    master   45m   v1.19.0+9f84db3
compute-2.example.com         Ready    worker   38m   v1.19.0+9f84db3
compute-3.example.com         Ready    worker   33m   v1.19.0+9f84db3
control-plane-3.example.com   Ready    master   41m   v1.19.0+9f84db3
----

Note

Some provider-formatted hostnames include IPv4 addresses. An OpenShift Container Platform node name typically reflects the hostname of a node. If node names in your output need to be provider-specific and require this format, use private IPv4 addresses. For example, you could use ip-10-0-48-9.example.com as a node name that includes a private IPv4 address.

IP addresses

You may include IPv4 addresses from test clusters in examples in the documentation, as long as they are private. Private IPv4 addresses fall into one of the following ranges:

10.0.0.0 to 10.255.255.255 (class A address block 10.0.0.0/8)
172.16.0.0 to 172.31.255.255 (class B address block 172.16.0.0/12)
192.168.0.0 to 192.168.255.255 (class C address block 192.168.0.0/16)

Replace all public IP addresses with an address from the following blocks. These address blocks are reserved for documentation:

192.0.2.0 to 192.0.2.255 (TEST-NET-1 address block 192.0.2.0/24)
198.51.100.0 to 198.51.100.255 (TEST-NET-2 address block 198.51.100.0/24)
203.0.113.0 to 203.0.113.255 (TEST-NET-3 address block 203.0.113.0/24)

Note	There might be advanced networking examples that require specific IP addresses, or cloud provider-specific examples that require a public IP address. Contact a subject matter expert if you need assistance with replacing IP addresses.

Links, hyperlinks, and cross references

Links can be used to cross-reference internal assemblies or send readers to external information resources for further reading.

In OpenShift Container Platform docs:

All links to internal content is created by using an xref, and each xref must have an anchor ID.
Only use xref in assemblies, not in modules.
All links to external websites are created by using the link attribute.
Links between different distributions, or distros, such as from ROSA to OpenShift Container Platform, are external links and not cross-references. These external links use link instead of xref and must be in distro-specific files or a conditionalized state to apply to the relevant distros.

Important

Do not split link paths across lines when wrapping text. This will cause issues with the documentation builds.

Lead-in link sentences

Using a lead-in link sentence that adheres to guidelines maintains consistency across OpenShift Container Platform documentation.

Lead-in link sentence style for non-xref situations

For situations where you cannot use the xref attribute, such as referencing a module within a module, ensure that you adhere to the following guidance for lead-in link sentences.

Use the following format when pointing to a section in the same document:
```
For more information, see "<section_name>".
```
Wrap the <section_name> string in quotation marks. The section name can be the title of a module or an assembly.
Do not state "in the Additional Resources section" or other variants. Mentioning the <section_name> is enough to prompt a documentation user to find the section in the same document.

Lead-in link sentence style for the xref attribute

For situations where you can use the xref attribute, adhere to the following guidance:

When pointing to a section (module) that exists in the same document (assembly), create an Additional resources section in the assembly file and then place the xref as a bulleted item under the Additional resources section. For example:
```
[role="_additional-resources"]
.Additional resources
* xref:../../../installing/installing_vsphere/installation-config-parameters-vsphere.adoc#installation-config-parameters-vsphere[Installation configuration parameters]
```
When pointing to a link in a section (module) that exists in another OpenShift Container Platform document (assembly), use the following format:
```
For more information on <topic>, see xref:<path_to_file>["<section_name>"] in _<document_name>_.
```

Note the quotation marks around <section_name> and the italics around <document_name>.

For more information about using xref, see Links, hyperlinks, and cross references.

Lead-in link sentence style for the link attribute

For situations where you can use the link attribute, adhere to the following guidance:

When pointing to a link that exists external to Red Hat’s customer portal documentation, add the link attribute, and use the <document_heading_name> (<document_source>) format. For example:
```
See link:https://aws.amazon.com/about-aws/global-infrastructure/localzones/features/[AWS Local Zones features] (AWS documentation).
```

Note

Certain Red Hat resources, such as Knowledgebase articles, exist in a separate server location to Red Hat customer portal documentation. For these resources, use the link attribute format.

For more information, see Links to Red Hat Knowledgebase articles (Red Hat supplementary style guide for product documentation).

For more information about using link, see Links, hyperlinks, and cross references.

Example URLs

To provide an example URL path that you do not want to render as a hyperlink, use this format:

`\https://www.example.com`

Internal cross-references

Use the relative file path (from the file you are editing to the file you are linking to), even if you are linking to the same directory that you are writing in. This makes search and replace operations to fix broken links much easier.

For example, if you are writing in architecture/core_concepts/deployments.adoc and you want to link to architecture/core_concepts/routes.adoc, then you must include the path back to the first level of the assembly directory:

xref:../../architecture/networking/routes.adoc#architecture-core-concepts-routes

Note	In OpenShift docs, you can only use `xref` in assemblies, not in modules.

Markup example of cross-referencing

For more information, see xref:../dev_guide/application_lifecycle/new_app.adoc#dev-guide-new-app[Creating an application].

Rollbacks can be performed using the REST API or the xref:../cli_reference/openshift_cli/get_started_cli.adoc#installing-openshift-cli[OpenShift CLI].

Rendered output of cross-referencing

For more information, see Creating an application.

Rollbacks can be performed using the REST API or the OpenShift CLI.

Links to external websites

If you want to link to a different website, use:

link:http://othersite.com/otherpath[friendly reference text]

Important

You must use link: before the start of the URL.

Important

You cannot link to a repository that is hosted on www.github.com. An exception to this rule is when autogenerated API reference content contains a link to www.github.com.

Tip	If you want to build a link from a URL without changing the text from the actual URL, just print the URL without adding a `[friendly text]` block at the end; it will automatically be rendered as a link.

Links to internal content

There are two scenarios for linking to other assemblies:

Link to another file that exists in the same directory.
Link to another file that exists in a separate directory.

The following examples use the example directory structure shown here:

/
/foo
/foo/bar.adoc
/baz
/baz/zig.adoc
/baz/zag.adoc

Link to assembly in same directory

xref:<filename>#anchor-id[friendly title]

You must use the .adoc file extension. The document processor will correctly link this to the resulting HTML file.

For example, using the above syntax, if you are working on zig.adoc and want to link to zag.adoc, do it this way:

xref:../zag.adoc#baz-zag[comment]

where baz-zag is the anchor ID at the top of the file zag.adoc.

Link to assembly in different directory

xref:../dir/<filename>.adoc#anchor-id[friendly title]

For example, if you are working on bar.adoc and you want to link to zig.adoc, do it this way:

For more information, see the xref:../baz/zig.adoc#baz-zig[ZIG manual].

Note	You must use the `.adoc` extension in order for the link to work correctly and you must specify an anchor ID.

Embedding an external file

You can embed content hosted outside the openshift-docs GitHub repository by using the include directive to target the URI of a raw file. This is helpful for cases where content frequently changes; you embed the raw file and the content auto-updates based on the changes made to the content on its host site.

Important

You are restricted to only embed files from GitHub repositories managed by the openshift GitHub user. You must also prefix your external file URI with https. URIs beginning with http are forbidden for security reasons and will fail the documentation build.

For example, if you want to embed the 01_vnet.json template, include the URI of its raw file version like this:

.`01_vnet.json` ARM template
[source,json]
----
include::https://raw.githubusercontent.com/openshift/installer/release-4.8/upi/azure/01_vnet.json[]
----

Note	Embedding external files is restricted for files that change frequently, like templates. You must ensure that embedded files are QE verified before they are updated on their host site.

Note	You must get approval from the Engineering, QE, and Docs teams before embedding an external file.

Embedding a local YAML file

You can embed local YAML files in AsciiDoc modules. Consider embedding a local YAML file when you have a complete and valid YAML file that you want to use. This is useful when you want to include a complete YAML CR in the docs. The YAML file that you include must be a local file maintained in the openshift-docs GitHub repository. Use the include directive to target the local file.

To use a local YAML file, add it to the snippets/ folder, and include it in your module. For example:

include::snippets/install-config.yaml[]

Note	Do not include lines by content ranges. This approach can lead to content errors when the included file is subsequently updated.

Important

If the YAML file you want to include is from a GitHub repository that is managed by the openshift GitHub user, link to the file directly rather than copying the file to the /openshift-docs folder.

Using AsciiDoc callouts in the YAML

You can use AsciiDoc callouts in the YAML file. Comment out the callout in the YAML file to ensure that file can still be parsed as valid YAML. Asciidoctor recognises the commented callout and renders it correctly in the output. For example:

apiVersion: v1 # <1>

Version and upgrade implications

Carefully consider the version and upgrade implications of including the local YAML file in your content. Including a local YAML file can increase the maintenance overhead for the content. If you have a doubt, talk to your content strategist or docs team lead.

Validating the local YAML file

Before you include the YAML file, use a YAML linter or the oc CLI to verify that the YAML is valid. For example, to validate the snippets/SiteConfig.yaml file using oc, log in to a cluster and run the following command from a terminal opened in the openshift-docs/ folder:

$ oc apply -f snippets/SiteConfig.yaml --dry-run=client

Example output

siteconfig.ran.openshift.io/example-sno created (dry run)

Running oc with the --dry-run=client switch does not succeed with an invalid YAML file.

Indicating Technology Preview features

To indicate that a feature is in Technology Preview, include the snippets/technology-preview.adoc file in the feature’s assembly or module to keep the supportability wording consistent across Technology Preview features. Provide a value for the :FeatureName: variable before you include this module.

:FeatureName: The XYZ plug-in
include::snippets/technology-preview.adoc[]

Indicating deprecated features

To indicate that a feature is deprecated, include the modules/deprecated-feature.adoc file in the feature’s assembly, or to each relevant assembly such as for a deprecated Operator, to keep the supportability wording consistent across deprecated features. Provide a value for the :FeatureName: variable before you include this module.

For more information on how this is applied, see this example PR.

Verification of your content

All documentation changes that update or add technical content must be verified by a QE team associate before merging. This QE verification process includes executing all procedures, confirming expected results, and confirming the accuracy of conceptual and reference content. The only exceptions are for typo-level changes, formatting-only changes, and other negotiated documentation sets and distributions.

If a documentation change is due to a Bugzilla bug or Jira issue, the bug/issue should be put on ON_QA when you have a PR ready. After QE approval is given (either in the bug/issue or in the PR), the QE associate should move the bug/issue status to VERIFIED, at which point the associated PR can be merged. It is also ok for the assigned writer to change the status of the bug/issue to VERIFIED if approval for the changes has been provided in another forum (slack, PR, or email). The writer should indicate that the QE team approved the change as a comment in the bug/issue.

Images

Image format

Use *.png format images.

Block images

To include a block image (an image on its own line):

Put the image file in the images folder.

Ensure that the folder containing your assembly contains an images symbolic link to the top-level images/ directory, otherwise the image will not be found when building the docs.
In the .adoc content, use this format to link to the image:
```
image::<image_filename>[<alt_text>]
```
Note the double :: instead of a single :, as seen in inline image usage. You only have to specify <image_filename> itself and not the full file path; the build mechanism automatically expands this appropriately.

Inline images (icons)

Inline images can be used to indicate graphic items in the web console, such as buttons or menu icons.

Inserting reusable images inline

To simplify reuse, the following common SVGs (the OpenShift web console uses the Font Awesome icon set) have already been added to the images folder with a user-defined entity added to the common-attributes.adoc module:

Icon	Entity	Alt text	File name
Kebab	`:kebab:`	Options menu	`ellipsis-v.svg`

When using inline, include the image after the UI element name. For example:

Click the *Options* menu {kebab}.

Inserting images inline without reuse

If you are inserting an image that is not part of the common-attributes.adoc module, then include the image using this formatting:

image:<image_filename>[title="<alt_text>"]

Note the single : instead of a double ::, as seen in block image usage.

For example:

image:manage-columns.png[title="Manage Columns icon"]

Formatting

For all of the system blocks including table delimiters, use four characters. For example:

|=== for tables
---- for code blocks

Note	You can use backticks or other markup in the title for a block, such as a code block `.Example` or a table `.Description` title.

Code blocks, command syntax, and example output

Code blocks are generally used to show examples of command syntax, example screen output, and configuration files.

The main distinction between showing command syntax and a command example is that a command syntax shows readers how to use the command without real values. An example command, however, shows the command with actual values with an example output of that command, where applicable.

Source tags for terminal commands and output

Use [source,terminal] for oc commands or any terminal commands to enable syntax highlighting. If you are also showing a code block for the output of the command, use [source,terminal] for that code block as well. Separate a command and its related example output into individual code blocks. See Single command per code block.

For example:

In the following example, the `oc get` operation returns a complete list of services that are currently defined:

[source,terminal]
----
$ oc get se
----

.Example output
[source,terminal]
----
NAME                LABELS                                    SELECTOR            IP                  PORT
kubernetes          component=apiserver,provider=kubernetes   <none>              172.30.17.96        443
kubernetes-ro       component=apiserver,provider=kubernetes   <none>              172.30.17.77        80
docker-registry     <none>                                    name=registrypod    172.30.17.158       5001
----

This renders as:

In the following example, the oc get operation returns a complete list of services that are currently defined:

$ oc get se

Example output

NAME                LABELS                                    SELECTOR            IP                  PORT
kubernetes          component=apiserver,provider=kubernetes   <none>              172.30.17.96        443
kubernetes-ro       component=apiserver,provider=kubernetes   <none>              172.30.17.77        80
docker-registry     <none>                                    name=registrypod    172.30.17.158       5001

Any [source] metadata must go on the line directly before the code block. Also, do not insert a space in between the [source] tag and the metadata.

For example:

[source,terminal]
----
$ oc get se
----

[source,yaml]
----
apiVersion: config.openshift.io/v1
kind: Scheduler
metadata:
  name: cluster
# ...
spec:
  defaultNodeSelector: node-role.kubernetes.io/app=
# ...
----

For Bash "here" documents use [source,terminal], such as the following example:

[source,terminal]
----
$ cat <<EOF| oc create -f -
apiVersion: v1
kind: Pod
metadata:
  name: mlistener
  labels:
    app: multicast-verify
EOF
----

Note	For bash scripts, use `[source,bash]`. For example: #!/bin/bash # optional argument handling if [[ "$1" == "config" ]] then echo $KUBECONFIG exit 0 fi echo "I am a plugin named kubectl-test"

The following guidelines go into more detail about specific requirements and recommendations when using code blocks:

Procedure step that introduces a command

If a step in a procedure is to run a command, make sure that the step text includes an explicit instruction to "run" or "enter" the command. In most cases, use one of the following patterns to introduce the code block:

<Step description> by running the following command:
<Step description> by entering the following command:
<Step description>, run the following command:
<Step description>, enter the following command:

No markup in code blocks

Do NOT use any markup in code blocks; code blocks generally do not accept any markup.

Empty line before code blocks

For all code blocks, you must include an empty line above a code block (unless that line is introducing block metadata, such as [source,terminal] for syntax highlighting).

Acceptable:

Lorem ipsum

----
$ lorem.sh
----

Not acceptable:

Lorem ipsum
----
$ lorem.sh
----

Without the line spaces, the content is likely to be not parsed correctly.

Source tags for programming languages

Use source tags for the programming language used in the code block to enable syntax highlighting. For example:

[source,yaml]
[source,go]
[source,javascript]
[source,jsx]
[source,bash]

Single command per code block

Do not use more than one command per code block.

When commands are bunched together, the copy to clipboard functionality might not break the lines up correctly. Using single command per code block makes it copy-and-paste friendly.

For example, the following must be split up into three separate code blocks:

To create templates you can modify, run the following commands:

[source,terminal]
----
$ oc adm create-login-template > login.html
----

[source,terminal]
----
$ oc adm create-provider-selection-template > providers.html
----

[source,terminal]
----
$ oc adm create-error-template > errors.html
----

Command syntax for replaceable values

To mark up command syntax, use the code block and wrap any replaceable values in angle brackets (<>) with the required command parameter, using underscores (_) between words as necessary for legibility.

Important

Do not italicize user-replaced values. This guideline is an exception to the Red Hat supplementary style guide for product documentation.

For example:

To view a list of objects for the specified object type, enter the following command:

[source,terminal]
----
$ oc get <object_type> <object_id>
----

This renders as:

To view a list of objects for the specified object type, enter the following command:
$ oc get <object_type> <object_id>

Note	Avoid using full command syntax inline with sentences.

Resource names in oc commands

When you specify resource names in oc commands, use the full name of the resource type by default. You can use the abbreviation of the resource type name if it improves readability, such as with very long commands, or to be consistent with existing content in the same assembly.

For example, use namespaces instead of ns and poddisruptionbudgets instead of pdb.

When referring to a path to a location that the user has selected or created, treat the part of the path that the user chose as a replaceable value. For example:

Create a secret that contains the certificate and key in the `openshift-config` namespace:

[source,terminal]
----
$ oc create secret tls <certificate> --cert=<path_to_certificate>/cert.crt --key=<path_to_key>/cert.key -n openshift-config
----

This renders as:

Create a secret that contains the certificate and key in the openshift-config namespace:
$ oc create secret tls <certificate> --cert=<path_to_certificate>/cert.crt --key=<path_to_key>/cert.key -n openshift-config

The following example shows a more complex use of user-chosen elements and prescriptive placement:

<resource_group_name>/providers/Microsoft.Compute/diskEncryptionSets/<disk_encryption_set_name>

Backslash for long lines of code

For long lines of code that you want to break up among multiple lines, use a backslash to show the line break. For example:

$ oc get endpoints --all-namespaces --template \
    '{{ range .items }}{{ .metadata.namespace }}:{{ .metadata.name }} \
    {{ range .subsets }}{{ range .addresses }}{{ .ip }} \
    {{ end }}{{ end }}{{ "\n" }}{{ end }}' | awk '/ 172\.30\./ { print $1 }'

Callouts in code blocks

If you must provide additional information on what a line of a code block represents, use callouts (<1>, <2>, etc.) to provide that information.

Use this format when embedding callouts into the code block:
```
----
code example 1 <1>
code example 2 <2>
----
<1> A note about the first example value.
<2> A note about the second example value.
```

If your command contains multiple lines and uses callout annotations, you must comment out the callout(s) in the codeblock, as shown in the following example:

To scale based on the percent of CPU utilization, create a HorizontalPodAutoscaler object for an existing object:

[source,terminal]
----
$ oc autoscale <object_type>/<name> \// <1>
  --min <number> \// <2>
  --max <number> \// <3>
  --cpu-percent=<percent> <4>
----
<1> Specify the type and name of the object to autoscale.
<2> Optional: Specify the minimum number of replicas when scaling down.
<3> Specify the maximum number of replicas when scaling up.
<4> Specify the target average CPU utilization over all the pods, represented as a percent of requested CPU.

If you must provide additional information on what a line of a code block represents and the use of callouts is impractical, you can use a description list to provide information about the variables in the code block. Using callouts might be impractical if a code block contains too many conditional statements to easily use numbered callouts or if the same note applies to multiple lines of the codeblock.

Be sure to introduce the description list with "where:" and start each variable description with "Specifies."
```
----
code <variable_1>
code <variable_2>
----
+
where:

<variable_1>:: Specifies the explanation of the first variable.
<variable_2>:: Specifies the explanation of the first variable.
```
For example:
```
[source,terminal]
----
$ oc annotate route <route_name> router.openshift.io/cookie_name="<cookie_name>"
----
+
where:

`<route_name>`:: Specifies the name of the route.
`<cookie_name>`:: Specifies the name for the cookie.
```

Signs and symbols in code blocks

If the user must run a command as root, use a number sign (#) at the start of the command instead of a dollar sign ($). For example:
```
# subscription-manager list
```

For snippets or sections of a file, use an ellipsis (…) to show that the file continues before or after the quoted block. For YAML, use ('#…') instead.

apiVersion: v1
kind: Pod
metadata:
  labels:
    test: liveness
# ...

or

Name:               ci-ln-iyhx092-f76d1-nvdfm-worker-b-wln2l
Roles:              worker
...
Taints:             node-role.kubernetes.io/infra:NoSchedule
...

Do not use […], <snip>, or any other variant.

Commands with jq

Do not use jq in commands (unless it is truly required), because this requires users to install the jq tool. Oftentimes, the same or similar result can be accomplished using jsonpath for oc commands.

For example, this command that uses jq:

$ oc get clusterversion -o json|jq ".items[0].spec"

can be updated to use jsonpath instead:

$ oc get clusterversion -o jsonpath='{.items[0].spec}{"\n"}'

YAML formatting for Kubernetes and OpenShift API objects

The following formatting guidelines apply to YAML manifests, but do not apply to the installation configuration YAML specified by install-config.yaml.

When possible, ensure that YAML is valid in a running cluster. You can validate YAML with oc apply with the following invocation:

$ oc apply -f test.yaml --dry-run=client

Required fields

Include the apiVersion and kind so that a user always knows the context of the YAML.
Include the full hierarchy to a deeply nested key.
For objects that are in the global scope, such as for config.openshift.io API group, always include the metadata.name for the object, which is usually cluster.

Example API object in the global scope

apiVersion: config.openshift.io/v1
kind: Scheduler
metadata:
  name: cluster
# ...
spec:
  defaultNodeSelector: node-role.kubernetes.io/app=
# ...

Example deeply nested key with full context for .ports array

apiVersion: v1
kind: Pod
metadata:
  name: pod1
  namespace: default
spec:
  containers:
  - name: web
    image: nginx
    ports:
    - name: web
      containerPort: 80
      protocol: TCP

YAML formatting

The following conventions govern the layout of YAML for API objects:

Begin YAML at the beginning of the left margin.
Use two-space indentation.
Indent arrays at the same depth as the parent field.
Include a space immediately after the colon for keys.
Use block style for complex strings, such as embedded JSON or text blocks. You can enable block style by specifying | or |- after a field and indenting the field content by two spaces, such as in the following example:
```
fieldName: |-
  This is a string.
  And it can be on multiple lines.
```
When truncating YAML, comment out the ellipsis (# …) because three dots (…) in YAML is actually a document end marker.
Use three hyphens (---) to separate YAML definitions in a single YAML file.

Example with array indentation flush with parent field

apiVersion: v1
kind: Pod
metadata:
  name: pod1
  labels:
  - key1: val1
  - key2: val2
spec:
# ...

Example with block string for annotation

apiVersion: v1
kind: Pod
metadata:
  name: pod1
  annotations:
    k8s.v1.cni.cncf.io/networks: |-
      [
        {
          "name": "net"
        }
      ]
spec:
# ...

Inline code or commands

Do NOT show full commands or command syntax inline within a sentence. The next section covers how to show commands and command syntax.

Only use case for inline commands would be general commands and operations, without replaceables and command options. In this case an inline command is marked up using the back ticks:

Use the `GET` operation to do x.

This renders as:

Use the GET operation to do x.

System messages

System messages include error, warning, confirmation, and information messages that are presented to the user in places such as the GUI, CLI, or system logs.

If a message is short enough to include inline, enclose it in back ticks:

Previously, image builds and pushes would fail with the `error reading blob from source` error message because the builder logic would compute the contents of new layers twice.

This renders as:

Previously, image builds and pushes would fail with the error reading blob from source error message because the builder logic would compute the contents of new layers twice.

If a message is too long to include inline, put it inside a code block with [source,text] metadata:

Previously, the AWS Terraform provider that the installation program used occasionally caused a race condition with the S3 bucket, and the cluster installation failed with the following error message:

[source,text]
----
When applying changes to module.bootstrap.aws_s3_bucket.ignition, provider level=error msg="\"aws\" produced an unexpected new value for was present, but now absent.
----

Now, the installation program uses different AWS Terraform provider code, which now robustly handles S3 eventual consistency, and the installer-provisioned AWS cluster installation does not fail with that error message.

This renders as:

Previously, the AWS Terraform provider that the installation program used occasionally caused a race condition with the S3 bucket, and the cluster installation failed with the following error message:
When applying changes to module.bootstrap.aws_s3_bucket.ignition, provider level=error msg="\"aws\" produced an unexpected new value for was present, but now absent.
Now, the installation program uses different AWS Terraform provider code, which now robustly handles S3 eventual consistency, and the installer-provisioned AWS cluster installation does not fail with that error message.

Note	Always refer to a message with the type of message it is, followed by the word "message". For example, refer to an error message as an "error message", and not simply as an "error".

Lists

Lists are created as shown in this example:

. Item 1 (2 spaces between the period and the first character)

. Item 2

. Item 3

This renders as:

Item 1

Item 2

Item 3

If you must add any text, admonitions, or code blocks you have to add the continuous +, as shown in the example:

. Item 1
+
----
some code block
----

. Item 2

. Item 3

This renders as:

Item 1
some code block
Item 2

Item 3

Support matrix tables

In tables that indicate version support, feature inclusion, or similar with a simple single-character indicator, use a capital letter "X" (X) centered in the cell. Other options, such as Unicode and emoji checkmarks, might lack screen reader support or require alt text.

Footnotes

Avoid footnotes when possible.

If you reference a footnote from only a single location, use the following syntax:

Footnote

footnote:[This is the footnote text.]

If you reference a footnote from multiple locations, set an attribute with the footnote text. As a consequence, this will duplicate the footnote text at bottom of the page.

Footnote with text set by an attribute

:note-text: This is a footnote.

This text has a footnote qualifier attached footnote:[{note-text}].

But this other text uses the same qualifier elsewhere footnote:[{note-text}].

Avoid using footnoteref.

Important

The footnoteref directive is deprecated in asciidoctor and causes a build warning when ascii_binder is run.

Footnote with reference

footnoteref:[ref-string, This is the footnote text.]

Alternative footnote styling in tables

For footnotes in tables, use the following syntax:

[cols="3",options="header"]
|===
|Header 1
|Header 2
|Header 3

|Item A ^[1]^
|Item B
|Item C ^[2]^

|Item D
|Item E ^[3]^
|Item F ^[3]^
|===
. A description.
. Another description.
. Two items relate to this description.

The notes immediately follow the table, instead of appearing at the bottom of the rendered assembly. With this manual method, you can also reuse the same footnote number for more than one reference.

Note

Because this method uses a standard ordered list, you might find it helpful to use numbers (such as 1. instead of .) while writing.
Add a space before the superscripted numbers with square brackets.
Older versions of these guidelines recommended the use of the deprecated [.small] style. The Red Hat Customer Portal does not support this style.

Collapsible content

You can collapse sections of content by using the collapsible option, which converts the Asciidoctor markup to HTML details and summary sections. The collapsible option is used at the writer’s discretion and is appropriate for considerably long code blocks, lists, or other such content that significantly increases the length of a module or assembly.

Note	You must set a title for the `summary` section. If a title is not set, the default title is "Details."

Collapsible content is formatted as shown:

.Title of the `summary` dropdown
[%collapsible]
====
This is content within the `details` section.
====

This renders as a dropdown with collapsed content:

Title of the summary dropdown

This is content within the details section.

If your collapsible content includes an admonition such as a note or warning, the admonition must be nested:

.Collapsible content that includes an admonition
[%collapsible]
====
This content includes an admonition.

[source,terminal]
----
$ oc whoami
----

[NOTE]
=====
Nest admonitions when using the `collapsible` option.
=====
====

This renders as:

Collapsible content that includes an admonition

This content includes an admonition.

$ oc whoami

Note	Nest admonitions when using the `collapsible` option.

Quick reference

Table 1. User accounts and info

Markup in command syntax	Description	Substitute value in Example block
`<username>`	Name of user account	user@example.com
`<password>`	User password	password

Important

Do not use a password format that matches the format of a real password. Documenting such a password format can cause the following issues:

Indicates that Red Hat publicly exposes sensitive data in their documentation.
Leads to additional security incidents that the Information Security, InfoSec, team must investigate. Such security incidents, although minor, can impact the InfoSec team’s resources and potentially delay them from focusing on actual security incidents.

Table 2. Projects and applications

Markup in command syntax	Description	Substitute value in Example block
`<project>`	Name of project	myproject
`<app>`	Name of an application	myapp

Additional resources sections

The following guidelines apply to all "Additional resources" sections:

You must include the [role="_additional-resources"] attribute declaration before the section heading.
You must not include paragraphs in the section. Use an unordered list.
The links and xrefs in the unordered list must contain minimal-length, human-readable text between the square brackets. This text is often the title of the linked page.
You must not include text outside of the square brackets. Text outside the brackets does not effectively render in an additional resources section box for a document on the Customer Portal.

Additionally, in an assembly, use == formatting for the section heading (== Additional resources). Use of this heading syntax at the assembly level indicates that the sections relate to the whole assembly. For example:

[role="_additional-resources"]
[id="additional-resources_configuring-alert-notifications"]
== Additional resources
* link:example.com[IANA example domain for documentation]
* xref:../installation/installing-the-product.adoc#installing-the-product[Installing the product]
* xref:../configuration/product-settings.adoc#installation-parameters_product-settings[Product installation configuration parameters]

Only use . formatting (.Additional resources) in a module or to follow a module in an assembly. Because you cannot use the xrefs in modules, this functions as a trailing include at the assembly level, where the . formatting of the include statement indicates that the resource applies specifically to the module and not to the assembly. For example:

[role="_additional-resources"]
.Additional resources
* link:example.com[IANA example domain for documentation]
* xref:../installation/installing-the-product.adoc#installing-the-product[Installing the product]
* xref:../configuration/product-settings.adoc#installation-parameters_product-settings[Product installation configuration parameters]

You can add link, hyperlinks, and cross references in either the Additional resources section or the Next steps section, but know the following differences:

Additional resources - module level: Requires the .Additional resources section heading. The listed resources link to other material closely related to the contents of the module. Focus on including the most relevant resources for the user, not a full list of possibly related resources.
Additional resources - assembly level: Requires the == Additional resources section heading with a unique anchor ID. If a resource applies to all of the modules in a user story, consider listing the resource in the Additional resources section of the assembly file.
Next steps: Provide links to resources that contain instructions that might be useful to the user after they complete a module or assembly. Do not use the Next steps section to provide detailed instructions to documentation users.

For more information about section types, see "Assembly guidelines" in the Modular documentation reference guide.

Admonitions

Admonitions such as notes and warnings are formatted as shown:

[ADMONITION]
====
Text for admonition
====

See the Red Hat Supplementary style guide for the valid admonition types and their definitions.

API object formatting

For terms that are API objects, the way they are written depends on whether the term is a general reference or an actual reference to the object.

General references

A general reference is any time you are speaking conceptually, or generally, about these components in a cluster.

When referring to API object terms in general usage, use lowercase and separate multi-word API objects. Default to following this guidance unless you are specifically interacting with/referring to the API object (see Object references).

For example:

pod
node
daemon set
config map
deployment
image stream
persistent volume claim

Examples of general references

Kubernetes runs your workload by placing containers into pods to run on nodes.

You must have at least one secret, config map, or service account.

The total number of persistent volume claims in a project.

Note that if an object uses an acronym or other special capitalization, then its general reference should honor that. For example, general references to APIService should be written as "API service", not "api service". Any other exceptions or special guidance are noted in the glossary.

Object references

An object reference is when you are referring to the actual instance of an API object, where the object name is important.

When referring to actual instances of API objects, use PascalCase and mark it up as monospace in backticks (``).

Note	Do not use backticks or other markup in assembly or module headings. You can use backticks or other markup in the title for a block, such as a code block `.Example` or a table `.Description` title.

Be sure to match the proper object type (or kind in Kubernetes terms); for example, do not add an "s" to make it plural. Only follow this guidance if you are explicitly referring to the API object (for example, when editing an object in the CLI or viewing an object in the web console).

For example:

Pod
Node
DaemonSet
ConfigMap
Deployment
ImageStream
PersistentVolumeClaim

Examples of API object references

After you create a `Node` object, or the kubelet on a node self-registers, the control plane checks whether the new `Node` object is valid.

The default amount of CPU that a container can use if not specified in the `Pod` spec.

Create a file, `pvc.yaml`, with the `PersistentVolumeClaim` object definition.

Note

Use "object", "resource", "custom resource", "spec", etc. as appropriate after the object reference. This helps with clarity and readability.

Another situation where this is necessary is when referring to the plural version of objects. Do not add an "s" to the end of an object name reference to make it plural. Use only the official kind of object (for example, seen when you run oc api-resources).

For example, the object kind for a node is Node, not Nodes. So do not write "You can create Nodes using kubectl." Instead, rewrite to something like "You can create Node objects using kubectl."

Operator capitalization

The term "Operator" is always capitalized. For example:

= Support policy for unmanaged Operators

Individual Operators have a `managementState` parameter in their configuration.

An Operator’s full name must be a proper noun, with each word initially capitalized. If it includes a product name, defer the product’s capitalization style guidelines. For example:

Red Hat OpenShift Logging Operator
Prometheus Operator
etcd Operator
Node Tuning Operator
Cluster Version Operator

Note

Red Hat Brand and Legal guidance for Operator names will likely differ. For marketing materials, they prefer lowercase names for anything that is not a Red Hat product.

However, the Brand team recognizes that there are different standards for marketing materials versus technical content. For this reason, the title case capitalization for Operator names in technical product documentation and OperatorHub is acceptable.

The "Naming" page by Red Hat Brand on the Source provides an overview of naming slide deck that also confirms this difference.

Declarative config examples

Many of our procedures provide imperative oc commands (which cannot be stored in a Git repo). Due to efforts around improving the experience for GitOps users, we sometimes also want to provide a declarative YAML example that achieves the same configuration. This allows users to store these YAML configurations in a Git repo and follow GitOps practices to configure OpenShift.

Important

When adding declarative examples to procedures, do not completely replace the imperative command with the declarative YAML example. Some users might still prefer the imperative option.

To add a declarative YAML example to a procedure step with an existing imperative command, add it in a "TIP" admonition by following the template in the example below. This example uses an imperative command (oc create configmap) to create a config map, and then provides the declarative YAML example of the ConfigMap object afterward.

* Define a `ConfigMap` object containing the certificate authority by using the following command:
+
[source,terminal]
----
$ oc create configmap ca-config-map --from-file=ca.crt=/path/to/ca -n openshift-config
----
+
[TIP]
====
You can alternatively apply the following YAML to create the config map:

[source,yaml]
----
apiVersion: v1
kind: ConfigMap
metadata:
  name: ca-config-map
  namespace: openshift-config
type: Opaque
data:
  ca.crt: <base64_encoded_CA_certificate_PEM>
----
====

This renders as:

Define a ConfigMap object containing the certificate authority by using the following command:
$ oc create configmap ca-config-map --from-file=ca.crt=/path/to/ca -n openshift-config
Tip
You can alternatively apply the following YAML to create the config map:
apiVersion: v1
kind: ConfigMap
metadata:
  name: ca-config-map
  namespace: openshift-config
type: Opaque
data:
  ca.crt: <base64_encoded_CA_certificate_PEM>

Note	If you are adding a particularly long YAML block, you can optionally use the `%collapsible` feature to allow users to collapse the code block.

Quick markup reference

Convention	Markup	Example rendered output
Code blocks	Use the following syntax for the `oc` command: ---- $ oc <action> <object_type> <object_name_or_id> ----	Use the following syntax for the `oc` command: $ oc <action> <object_type> <object_name_or_id>
Use backticks for all non-GUI "system items", including: Inline commands, operations, literal values, variables, parameters, settings, flags, environment variables, user input System term/item, user names, unique or example names for individual API objects/resources (e.g., a pod named `mypod`), daemon, service, or software package RPM packages File names or directory paths	`oc get` Set the `upgrade` variable to `true`. Use the `--amend` flag. Answer by typing `Yes` or `No` when prompted. `user_name` `service_name` `package_name` `filename`	Use the `oc get services` command to get a list of services that are currently defined. Use the `--amend` flag. Set the `upgrade` variable to `true`. Answer by typing `Yes` or `No` when prompted. `cluster-admin` user `firewalld` service `rubygems` RPM package The `express.conf` configuration file is located in the `/usr/share` directory.
System or software variable to be replaced by the user	`<project>` `<deployment>` `<install_mode_value>`	Use the following command to roll back a Deployment, specifying the Deployment name: `oc rollback <deployment>` Apply the new configuration file: `oc apply -f <path_to_configuration_file>/<filename>.yaml`
Use single asterisks for web console / GUI items (menus, buttons, page titles, etc.). Use two characters to form the arrow in a series of menu items (`->`).	Choose Cluster Console from the list. Navigate to the Operators -> Catalog Sources page. Click Create Subscription.	Choose Cluster Console from the list. Navigate to the Operators → Catalog Sources page. Click Create Subscription.
Use underscores to emphasize the first appearance of a new term.	An _Operator_ is a method of packaging, deploying, and managing a Kubernetes application.	An Operator is a method of packaging, deploying, and managing a Kubernetes application.
Use of underscores for general emphasis is allowed but should only be used very sparingly. Let the writing, instead of font usage, create the emphasis wherever possible.	Do _not_ delete the file.	Do not delete the file.
Table style operators	A style operator styles the content of a table cell or a table column, depending on where you set the operator. Using the literal (`l`) operator in a column might impact the documentation platform’s copy and paste functionality. For example, when you paste copied code block content to a location, the first styled literal value in an assembly is pasted instead of the intended code block. When using any style operator in a table, check all copy and paste functions that follow the defined style operator work correctly for all code blocks in an assembly. See Cell styles and their operators (Asciidoctor Documentation)	.Required parameters [cols=".^2m,.^3,.^5a",options="header"]
Footnotes	A footnote is created with the footnote macro. If you plan to reference a footnote more than once, use the ID footnoteref macro. The Customer Portal does not support spaces in the footnoteref. For example, "dynamic PV" should be "dynamicPV".	For footnote and footnoteref syntax, see AsciiDoctor documentation.

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Directory names

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Discrete headings

Anchoring titles and section headings

Anchoring in assembly files

Anchoring in module files

Anchoring "Prerequisites", "Additional resources", and "Next steps" titles in assemblies

Writing assemblies

Writing concepts

Writing procedures

Writing text snippets

Auto-generated content

Using conscious language

Adding a subsection on making open source more inclusive

Product title and version

Third-party vendor product names

Conditional content

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Conditionals for different assemblies

Node names

IP addresses

Links, hyperlinks, and cross references

Lead-in link sentences

Lead-in link sentence style for non-xref situations

Lead-in link sentence style for the xref attribute

Lead-in link sentence style for the link attribute

Example URLs

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Links to external websites

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Embedding an external file

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Using AsciiDoc callouts in the YAML

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Validating the local YAML file

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Indicating deprecated features

Verification of your content

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Image format

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Inserting images inline without reuse

Formatting

Code blocks, command syntax, and example output

Source tags for terminal commands and output

Procedure step that introduces a command

No markup in code blocks

Empty line before code blocks

Source tags for programming languages

Single command per code block

Command syntax for replaceable values

Resource names in oc commands

Backslash for long lines of code

Callouts in code blocks

Signs and symbols in code blocks

Commands with jq

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Required fields

YAML formatting

Inline code or commands

System messages

Lists

Support matrix tables

Footnotes