Tasks

Tasks control the actions that Razor performs on a node, most commonly the installation of an operating system. A task consists of a metadata file, and a number of ERB templates. Currently, the metadata file is a YAML file with the name metadata.yaml in a ${name}.task folder in the tasks folder. The task name supports a forward-slash /, which allows tasks to be physically organized in subfolders (eg. A task name of Windows/10 would be stored in tasks/Windows/10.task)

Here is a sample of that file's syntax, located at e.g. tasks/some_task.task/metadata.yaml:

os_version: 42
description: Some OS version 42
base: some_other_task
boot_sequence:
  1: boot_install
  2: boot_again
  default: boot_local

This task is called some_task since the folder name is some_task.task. The os_version and description fields should be self explanatory. The base field indicates this task is derived from a different task, which affects how templates are found (below). The boot_sequence governs how Razor should respond to repeated boot requests of a node. In the above example, on the first boot request after a policy using this task has been bound to the node, the server will respond with the boot_install.erb template, on the second boot request with the boot_again.erb template, and on all following requests with the boot_local.erb template.

Templates are looked for in the following directories, in this order:

1. $name.task
2. $base.task (if the task is derived from another)
3. common

These directories are taken relative to the task_path configuration setting, which is a colon separated list of directories.

Templates can use the following helper functions:

• file_url(template): the URL to the (interpolated) template; e.g., a kickstart script might download a post_install script with curl <%= file_url("post_install") %> > /tmp/post_insall.sh
• log_url(message, severity): generate a URL that, when a GET is issued against it, logs message with severity against the current node
• store_url(vars): a URL that will store vars with the node on the server; currently only ip is supported as a variable
• repo_url(path): a URL to path within the repo currently being installed, e.g. <%= repo_url("/isolinux/vmlinux") %>
• config[key]: the configuration value for key