Tasks describe a process or collection of actions that should be performed while Razor provisions machines. Tasks can be used to designate an operating system or other software that should be installed, where to get it, and the configuration details for the installation.
Tasks are structurally simple. They consist of a YAML metadata file and any number of ERB templates. You include the tasks you want to run in your policies (policies are described in the next section). The templates are used to generate things like the iPXE script that will boot a node into the installer, and automated installation files like kickstart, preseed or unattended files.
Razor provides a handful of existing tasks, or you can create your own. The existing tasks are primarily for installing supported operating systems.
Tasks are stored in the file system. The task_path
class parameter of the pe_razor
module determines where Razor looks for tasks. The parameter can include a colon-separated list of paths. Relative paths in that list are taken to be relative to the top-level Razor directory. For example, setting task_path
to /opt/puppet/share/razor-server/tasks:/home/me/task:tasks
makes Razor search these three directories in that order for tasks.
Storage directories
There are two directories that store tasks:
/opt/puppetlabs/server/apps/razor-server/share/razor-server/tasks
stores default tasks shipped with the product./etc/puppetlabs/razor-server/tasks
stores custom tasks.
Tip: We recommend not modifying the directory or tasks at /opt...
, but you can copy tasks from there to the custom task directory and modify them as needed.
Task metadata
Tasks can include the following metadata in the task’s YAML file. This file
is called metadata.yaml
and exists in tasks/<NAME>.task
where NAME
is
the task name. Therefore, the task name looks like this:
tasks/<NAME>.task/metadata.yaml
.
---
description: HUMAN READABLE DESCRIPTION
os: OS NAME
os_version: OS_VERSION_NUMBER
base: TASK_NAME
boot_sequence:
1: boot_templ1
2: boot_templ2
default: boot_local
Only os_version
and boot_sequence
are required. The base
key allows
you to derive one task from another by reusing some of the base
metadata
and templates. If the derived task has metadata that’s different from the
metadata in base
, the derived metadata overrides the base task’s
metadata.
The boot_sequence
hash indicates which templates to use when a node using
this task boots. In the example above, a node will first boot using
boot_templ1
, then using boot_templ2
. For every subsequent boot, the
node will use boot_local
.
Writing task templates
Task templates are ERB templates and are searched in all the directories
in the task_path
configuration setting. Templates are searched in
the subdirectories in this order:
name.task
base.task
# If the task has a base task.common
Template helpers
Templates can use the following helpers to generate URLs that point back to
the server; all of the URLs respond to a GET
request, even the ones that
make changes on the server:
task
: Includes attributes such asname
,os
,os_version
,boot_seq
,label
,description
,base
, andarchitecture
.node
: Includes attributes such asname
,metadata
, andfacts
.repo
: Includes attributes such asname
,iso_url
,url
.file_url(TEMPLATE)
: The URL that will retrieveTEMPLATE.erb
(after evaluation) from the current node’s task.repo_url(PATH)
: The URL to the file atPATH
in the current repo.log_url(MESSAGE, SEVERITY)
: The URL that will logMESSAGE
in the current node’s log.node_url
: The URL for the current node.store_url(VARS)
: The URL that will store the values in the hashVARS
in the node. Currently only changing the node’s IP address is supported. Usestore_url("ip" => "192.168.0.1")
for that.stage_done_url
: The URL that tells the server that this stage of the boot sequence is finished, and that the next boot sequence should begin upon reboot.broker_install_url
: A URL from which the install script for the node’s broker can be retrieved. You can see an example in the script, os_complete.erb, which is used by most tasks.
Each boot (except for the default boot) must culminate in something akin to
curl <%= stage_done_url %>
before the node reboots. Omitting this will
cause the node to reboot with the same boot template over and over again.
The task must indicate to the Razor server that it has successfully
completed by doing a GET
request against stage_done_url("finished")
,
for example using curl
or wget
. This will mark the node installed
in
the Razor database.
You use these helpers by causing your script to perform an HTTP GET
against the generated URL. This might mean that you pass an argument like
ks=<%= file_url("kickstart")%>
when booting a kernel, or that you put
curl <%= log_url("Things work great") %>
in a shell script.
Related links: