Writing guide

This page contains detailed information on how to become a successful Juju documentation writer. Welcome to the club.

An individual doc contribution ends up as a PR (pull request) on GitHub. The process involved in producing one is described on the project README page.

Style and language

Please follow these guidelines for style and language:

  • Use a spell checker.
  • Resist being overly formal.
  • Verify hyperlinks and examples.
  • Target audience: intermediate system administrator, not a developer.
  • Use British English (en-GB). See language details, including a comparison with American English (en-US).
  • Use a maximum of 79 columns for files. Here are instructions for the vim editor.
  • An exception to the above is a hyperlink. Never break one with a carriage return. This includes the [text][label] and [label]: destination combinations. See hyperlinks.

GitHub Flavored Markdown

This documentation is written in GitHub Flavored Markdown. GFM conventions have been added to support features such as foldouts and admonishments.

GFM is very easy to write with. Get started by looking over the below resources:


Metadata can be included in any file. Currently, this is used for:

  • title element
  • TODO list (file improvements)
  • table of contents

This information is written as key:value pairs at the very top of the page. For example:

Title: Install from ISO
TODO: images need updating when Ubuntu 17.04 is released
      check for changes to bug https://pad.lv/1625211 and modify text accordingly
table_of_contents: True

# Title of document

Text goes here blah blah blah
  • The TODO items must be left-aligned as shown above.
  • The table of contents will contain only level 2 headers.
  • The metadata section is terminated by a blank line.


Headers are simple to create:

# Top level header (typically the same as the Title element)
## Second level header
### Third level header

Code blocks

A code block is enclosed by three backticks and includes the type of code:

juju command do something
juju command do something else

The most common types used are: bash, yaml, json, and no-highlight. The last is like a miscellaneous type. It is often used to display command output.

Inline code

Use a backtick to inline commands and other literals. For instance, to get this:

A controller is created with the bootstrap command.

you would write this:

A controller is created with the `bootstrap` command.


An admonishment distinguishes information from the rest of the text. The syntax begins with 3 exclamation points:

!!! [admonishment-type] "[title]": 
    [aligned text]


  • admonishment-type can be 'Note', 'Warning', 'Positive', or 'Negative'.
  • title is an optional title (visible in HTML)
  • aligned text is the text

When a value for 'title' is omitted, the default will be the type itself. If the 'title' has a null value (i.e. "") then no title will be displayed.

Admonishment examples

A standard 'Note' type admonishment:

!!! Note: 
    If KVM-backed nodes are used, ensure that the 'maas' user on the rack
    controller can connect to the KVM host using a passphraseless private SSH

A standard 'Warning' type admonishment:

!!! Warning: 
    Data will be lost unless you do the right thing.

A 'Positive' type admonishment with title:

!!! Positive "High score":
    A positive note that should include a title.

A 'Negative' type admonishment with title:

!!! Negative "Game over": 
    A negative note that should include a title.

A 'Positive' type admonishment with no title:

!!! Positive "": 
    I'm done, and I feel fine.

The above examples will appear as:

Note: If KVM-backed nodes are used, ensure that the 'maas' user on the rack controller can connect to the KVM host using a passphraseless private SSH key.

Warning: Data will be lost unless you do the right thing.

High score: A positive note that should include a title.

Game over: A negative note that should include a title.

I'm done, and I feel fine.


Occasionally it may be appropriate to include a comment to explain or organize some text. This ends up as an HTML comment which can be read online so take it seriously:

The below text may be removed soon.


When a page contains a lot of extraneous information such as walkthroughs containing many images or reference tables, a foldout can be used. This will create a collapsed header which, when clicked, will expand to display all the content below it.

^# Header
  Content can be multi-paragraphed and will be sent through the Markdown parser

  as long as content is continually indented under the header.

Links to internal files or external URLs use the following format:

[visible text][label]

The visible text is what will appear on the web page. The label is used to refer to the destination, which is placed at the bottom of the file:

<!-- LINKS -->

[label]: destination

For example:

- For more on this topic see [DHCP][dhcp].
- To understand haproxy, see the [upstream configuration manual][upstream-haproxy-manual].


[dhcp]: installconfig-networking-dhcp.md
[upstream-haproxy-manual]: http://cbonte.github.io/haproxy-dconv/1.6/configuration.html

The visible text should use an active style as opposed to a passive style. For instance, try to avoid:

A [proxy][maas-proxy] can optionally be configured.


  • An internal page is referred to by its source filename (i.e. .md not .html).
  • Try to use the same label:destination pair throughout the documentation.


An image should not be overly cropped - allow for context.

When ready, upload the image to an image host - e.g. https://manager.assets.ubuntu.com.

In terms of linking, they are managed very similarly to hyperlinks. However, they are placed on their own line; are preceded by an exclamation point; and both the label and destination have a specific naming convention:

![alt attribute][img__webui_descriptor]

The bottom of the file will look like:

[img__webui_descriptor]: https://assets.ubuntu.com/v1/hash-filename__webui_descriptor.png


  • filename: name of file containing the image (omit the extension '.md')
  • webui: version of the Juju GUI corresponding to the image of the web UI
  • alt attribute: text that is shown in place of the image if the latter cannot be displayed for some reason
  • descriptor: a short description of the image (e.g. 'enable-dhcp')

For example:

![enable dhcp][img__2.1_enable-dhcp]
![enable fire alarm][img__enable-fire-alarm]


[img__2.1_enable-dhcp]: https://assets.ubuntu.com/v1/a2e5f7-installconfig-networking-dhcp__2.1_enable-dhcp.png
[img__enable-fire-alarm]: https://assets.ubuntu.com/v1/b4e32a-installconfig-networking-dhcp__enable-fire-alarm.png

If the image is not of the Juju web UI then simply omit the version part, like in the second image above.


Do not use a "Caps Everywhere" style. It is only used in level one headers and the title metadata. References (visible text) to these page titles (including the navigation) should just capitalize the first letter. Obviously, this does not pertain to words that should always be capitalized according to basic grammar rules (e.g. acronyms, proper nouns).

Adding a page (file) to the documentation may require the altering of src/en/metadata.yaml. Doing so will insert an entry into the left navigation pane (the menu) on the website. This is considered a major change so ensure your PR includes a comment highlighting this change and why it is needed.

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