Alternative Harness Guide

This guide is for Beaker users who want to use a different harness than Beah in their recipes.

Selecting an alternative harness in your recipe

Use the harness kickstart metadata variable to select an alternative harness.

The default value is beah, which activates the traditional kickstart template logic for configuring /etc/beah_beaker.conf and installing Beah.

When set to any other value, Beah-specific parts of the template are skipped. Instead, the kickstart will contain a command to install the named harness. For example:

<recipe ks_meta="harness=my-alternative-harness">

will cause the following command to appear in the kickstart %post section:

yum -y install my-alternative-harness

The value of the harness variable will be substituted directly into the yum install command line. You can give a package name, assuming your recipe also defines a custom yum repo where your harness will be installed from. Or you can give an absolute URL to your harness package. If necessary, you can pass multiple package names or URLs separate by spaces (remember to quote the value correctly).

Environment variables

Beaker configures the following system-wide environment variables. When installed, a harness implementation must arrange to start itself on reboot and then configure itself according to these values.

Base URL of the Beaker lab controller. The harness communicates with Beaker by accessing HTTP resources (described below) underneath this URL.
The fully-qualified domain name of the lab controller to which this system is attached. This will always match the hostname portion of BEAKER_LAB_CONTROLLER_URL but is provided for convenience.
The ID of the Beaker recipe which this system is currently running. Use this to fetch the recipe details from the lab controller as described below.
Base URL of the Beaker server. Note that the harness should not communicate with the server directly, but it may need to pass this value on to tasks.

HTTP resources

The lab controller exposes the following HTTP resources for use by the harness. All URL paths given below are relative to the value of the BEAKER_LAB_CONTROLLER_URL environment variable.

When using the POST method with the resources described below, the request body must be given as HTML form data (application/x-www-form-urlencoded).

GET /recipes/(recipe_id)/

Returns recipe details. Response is in Beaker job results XML format, with application/xml content type. The root node of the returned XML will be <job/>, which will contain the requested recipe element. Note that guest recipes will be nested within a partially populated <recipe/>.

GET /recipes/(recipe_id)/watchdog

Returns the number of seconds remaining on the watchdog timer for a recipe.

The response is a JSON object with a key seconds.

POST /recipes/(recipe_id)/watchdog

Extends the watchdog for a recipe.

Form Parameters:
  • seconds – The watchdog kill time is updated to be this many seconds from now.
Status Codes:
POST /recipes/(recipe_id)/status

Updates the status of all tasks which are not already finished.

Form Parameters:
  • status – The new status. Must be Aborted.
Status Codes:

Typically the harness will update the status of each task individually as it runs (see below). This is provided as a convenience only, to abort all tasks in a recipe.

PATCH /recipes/(recipe_id)/tasks/(task_id)/

Updates the attributes of a task. The request must be application/x-www-form-urlencoded or application/json containing one or more attributes to update.

Form Parameters:
  • status – Current status of the task. Must be Running, Completed, or Aborted (see the note below about valid transitions).
  • name – Name of the task. This is presented to the user in the recipe results. The harness may determine the name by reading it from metadata associated with the task (for example, RHTS-format tasks define their name in testinfo.desc).
  • version – Version of the task which is running. This is recorded in the recipe results to aid in debugging and reproduceability.
Status Codes:
  • 200 OK – The task was successfully updated. The response body contains the updated attributes.
  • 400 Bad Request – Bad parameters were given.
  • 409 Conflict – The requested status transition is invalid.

Tasks in Beaker always start out having the New status. Once a task is Running, its status may only change to Completed, meaning that the task has completed execution, or Aborted, meaning that the task’s execution did not complete (or never began) because of some unexpected condition. Once a task is Completed or Aborted its status may not be changed. Attempting to change the status in a way that violates these rules will result in a 409 Conflict response.

POST /recipes/(recipe_id)/tasks/(task_id)/status

Deprecated since version 0.16: Use PATCH /recipes/(recipe_id)/tasks/(task_id)/ instead.

Updates the status of a task. See the note above about valid transitions for the status attribute.

Form Parameters:
  • status – The new status. Must be Running, Completed, or Aborted.
Status Codes:
POST /recipes/(recipe_id)/tasks/(task_id)/results/

Records a task result. Returns a 201 Created response with a Location header in the form /recipes/(recipe_id)/tasks/(task_id)/results/(result_id).

Results may not be recorded against a task after it has finished.

Form Parameters:
  • result – The result. Must be Pass, Warn, Fail, Skip, or None.
  • path – Path of the result. Conventionally the top-level result will be recorded as $TEST, with sub-results as $TEST/suffix, but this is not required. If not specified, the default is /.
  • score – Integer score for this result. The meaning of the score is defined on a per-task basis, Beaker intentionally enforces no meaning.
  • message – Textual message to accompany the result. This is typically short, and is expected to be displayed in one line in Beaker’s web UI. Use the log uploading mechanism to record test output.
Status Codes:
PUT /recipes/(recipe_id)/logs/(path: path)
PUT /recipes/(recipe_id)/tasks/(task_id)/logs/(path: path)
PUT /recipes/(recipe_id)/tasks/(task_id)/results/(result_id)/logs/(path: path)

Stores a log file.

Log files may not be stored against a recipe or task after it has finished.

Status Codes:

Use the Content-Range header to upload part of a file.

GET /recipes/(recipe_id)/logs/(path: path)
GET /recipes/(recipe_id)/tasks/(task_id)/logs/(path: path)
GET /recipes/(recipe_id)/tasks/(task_id)/results/(result_id)/logs/(path: path)

Returns an uploaded log file.

Use the Range header to request part of a file.

GET /recipes/(recipe_id)/logs/
GET /recipes/(recipe_id)/tasks/(task_id)/logs/
GET /recipes/(recipe_id)/tasks/(task_id)/results/(result_id)/logs/

Returns a listing of all uploaded logs.

Possible response formats include an HTML index (text/html) or an Atom feed (application/atom+xml). Use the Accept header to request a particular representation. The default is HTML.

PUT /power/(fqdn)/

Commands Beaker to perform given power action on system defined by FQDN. The request must be application/x-www-form-urlencoded or application/json.

Form Parameters:
  • action – Must be on, off, or reboot.
Status Codes:
HEAD /healthz/

Check health status of Harness API.

Status Codes:
GET /healthz/

Check health status of Harness API.

The response is a message signaling a healthy state.

Status Codes: