DataCentred Staging Preseed Server

Description

Simple REST daemon which listens for preseed requests when installing a host from a network boot image. This is responsible for serving dynamic preseed content used to install the machine, and also finish scripts to install customisations expected to be in place.

The controlling process first creates an ephemeral host entry identifying the templates to use for various API calls and any metadata used to render those templates. A host is booted into a network installer which then contacts the preseed server which generates pressed and finish scripts on demand. Once complete the calling process can destroy the host entry and continue.

At present templates are served statically. They can be found in the /views directory.

Building

apt-get -y install gcc make libffi-dev
gem install fpm
gem build staging-preseed-server.gemspec 
fpm -s gem -t deb \
  --depends ruby-sinatra \
  --gem-package-name-prefix ruby \
  --deb-systemd etc/systemd/system/staging-preseed-server.service \
  --deb-default etc/default/staging-preseed-server \
  staging-preseed-server-x.y.z.gem

API

Requests other than pressed and finish resources are expected to send and receive JSON where data is transfered.

All requests may respond with a 500 error, typically an exception was thrown and more information can be gained from the server logs.

GET /hosts

Return a list of all known hosts

Response

Code	Meaning
200	Command success

GET /hosts/:host

Return a single host

Response

Code	Meaning
200	Command success
404	Host not found

Parameter	Type	Value
preseed	String	Name of a preseed template to use
finish	String	Name of a finish template to use
metadata	Hash	Hash of arbitrary data for preseed/finish template generation

Example

{
  "preseed": "preseed.xenial-default.erb",
  "finish": "finish.xenial-default.erb",
  "metadata": {
    "finish_url": "http://10.25.192.254:8421/hosts/ns.example.com/finish",
    "networks": {
      "ens3": {
        "address": "10.25.192.250",
        "netmask": "255.255.255.0",
        "gateway": "10.25.192.1",
        "nameserver": "10.25.192.250 10.25.192.251",
      }
    }
  }
}

POST /hosts/:host

Accepts an arbitrary JSON hash of parameters to be used in template generation

Request

Parameter	Type	Flags	Value
preseed	String	Required	Name of a preseed template to use
finish	String	Required	Name of a finish template to use
metadata	Hash	Optional	Hash of arbitrary data for preseed/finish template generation

Response

Code	Meaning
201	Resource created successfully
209	Resource already exists

DELETE /hosts/:host

Deletes a host from the preseed server

Response

Code	Meaning
204	Resource deleted successfully
404	Resource not found

GET /hosts/:host/preseed

Get a rendered preseed file

Response

Code	Meaning
200	Command success
404	Host not found

GET /hosts/:host/finish

Get a rendered finish script

Response

Code	Meaning
200	Command success
404	Host not found