Pallet Jack

Pallet Jack is a lightweight configuration management database, utilizing the power of a Posix file system to store yaml serialized key-value trees.

A database is created from a warehouse (directory) of different kinds (directory) of pallets (directory), each containing boxes (yaml files) with keys. Pallets can contain other pallets, recursively, to form hierarchical inheritance. Pallets can also contain references to other pallets (symlinks) out of hierarchy, to build a Directed Acyclic Graph of key-value search nodes.

The entire structure is indended to live beside configuration management code and data in a version control system repository, to enable tagged releases of both code, data and metadata.

The toplevel transforms.yaml file defines key-value transforms to perform when loading the database, e.g. synthesize key-values from pallet metadata.

warehouse
├── building
│   └── 1
│       └── location.yaml
├── chassis
│   └── Example:FastServer-128:1234ABCD
│       ├── identity.yaml
│       ├── location.yaml
│       └── rack -> ../../rack/1-A-2/
├── domain
│   └── example.com
│       ├── dns.yaml
│       ├── ipv4_network -> ../../ipv4_network/192.168.0.0_24/
│       └── services.yaml
├── ipv4_interface
│   ├── 192.168.0.1
│   │   ├── dns.yaml
│   │   ├── domain -> ../../domain/example.com/
│   │   ├── ipv4_network -> ../../ipv4_network/192.168.0.0_24/
│   │   ├── phy_nic -> ../../phy_nic/14:18:77:ab:cd:ef/
│   │   └── system -> ../../system/vmhost1/
│   └── 192.168.0.2
│       ├── domain -> ../../domain/example.com/
│       ├── ipv4_network -> ../../ipv4_network/192.168.0.0_24/
│       ├── phy_nic -> ../../phy_nic/52:54:00:12:34:56/
│       └── system -> ../../system/testvm/
├── ipv4_network
│   └── 192.168.0.0_24
│       ├── dhcp.yaml
│       └── identity.yaml
├── machine
│   ├── testvm
│   │   ├── host -> ../../system/vmhost1/
│   │   └── type.yaml
│   └── vmhost1
│       ├── chassis -> ../../chassis/Example:FastServer-128:1234ABCD/
│       └── type.yaml
├── netinstall
│   └── CentOS-7.4.1708-x86_64
│       ├── Kickstart_sda
│       │   └── kickstart.yaml
│       ├── Kickstart_vda
│       │   └── kickstart.yaml
│       ├── Manual
│       │   └── kickstart.yaml
│       └── os -> ../../os/CentOS-7.4.1708-x86_64
├── os
│   └── CentOS-7.4.1708-x86_64
│       └── kickstart.yaml
├── phy_nic
│   ├── 14:18:77:ab:cd:ef
│   │   ├── chassis -> ../../chassis/Example:FastServer-128:1234ABCD/
│   │   └── location.yaml
│   └── 52:54:00:12:34:56
│       ├── identity.yaml
│       └── phy_nic -> ../../phy_nic/14:18:77:ab:cd:ef/
├── rack
│   └── 1-A-2
│       ├── location.yaml
│       └── room -> ../../room/server-room-1/
├── room
│   └── server-room-1
│       ├── building -> ../../building/1
│       ├── identity.yaml
│       └── location.yaml
├── service
│   ├── dhcp-server
│   │   ├── kea.yaml
│   │   └── example-com
│   │       └── kea.yaml
│   └── dns-resolver
│       └── example-com
│           └── unbound.yaml
├── system
│   ├── testvm
│   │   ├── architecture.yaml
│   │   ├── domain -> ../../domain/example.com/
│   │   ├── machine -> ../../machine/testvm/
│   │   ├── netinstall -> ../../netinstall/CentOS-7.4.1708-x86_64/Kickstart_vda/
│   │   └── role.yaml
│   └── vmhost1
│       ├── architecture.yaml
│       ├── domain -> ../../domain/example.com/
│       ├── machine -> ../../machine/vmhost1/
│       ├── netinstall -> ../../netinstall/CentOS-7.4.1708-x86_64/Kickstart_sda/
│       └── role.yaml
└── transforms.yaml

% irb -r palletjack
2.3.1 :001 > jack = PalletJack.load('examples/warehouse')
2.3.1 :002 > testvm = jack.fetch(kind: 'system', name: 'testvm')
2.3.1 :003 > testvm['host.type']
 => "virtual"
2.3.1 :004 > jack.each(kind: 'system') {|pallet| puts "#{pallet['net.dns.name']}: #{pallet['chassis.serial']}" }
vmhost1: 1234ABCD
testvm: 1234ABCD
2.3.1 :005 > jack.each(kind: 'system', all?: {'host.type' => 'virtual'}) {|system| puts system['net.dns.name'] }
testvm

Installation

Add this line to your application's Gemfile:

gem 'palletjack'

And then execute:

$ bundle

Or install it yourself as:

$ gem install palletjack

Creating warehouse objects

Warehouse objects are simple directories, so you can create them using mkdir. To simplify the process, there are some tools that create objects with standard links and YAML structures for you. Example:

$ create_domain --warehouse /tmp/warehouse --domain example.com --network 192.168.42.0/24
$ create_system --warehouse /tmp/warehouse --system vmhost --domain example.com --os CentOS-7.4.1708-x86_64
$ create_ipv4_interface --warehouse /tmp/warehouse --system vmhost --domain example.com --mac 52:54:00:8d:be:fe --ipv4 192.168.42.1 --network 192.168.42.0/24
$ dump_pallet --warehouse /tmp/warehouse --type ipv4_interface 192.168.42.1

---
pallet:
  ipv4_network: 192.168.42.0_24
  boxes: []
  references:
    ipv4_network: 192.168.42.0_24
    domain: example.com
    phy_nic: 52:54:00:8d:be:fe
    os: CentOS-7.4.1708-x86_64
    system: vmhost
  domain: example.com
  phy_nic: 52:54:00:8d:be:fe
  os: CentOS-7.4.1708-x86_64
  system: vmhost
  ipv4_interface: 192.168.42.1
net:
  dhcp:
    tftp-server: ''
    boot-file: ''
  ipv4:
    gateway: ''
    prefixlen: '24'
    cidr: 192.168.42.0/24
    address: 192.168.42.1
  dns:
    resolver:
    - ''
    ns:
    - ''
    soa-ns: ''
    soa-contact: ''
    domain: example.com
    name: vmhost
    fqdn: vmhost.example.com
  service:
    syslog:
    - address: syslog-archive.example.com
      port: 514
      protocol: udp
    - address: logstash.example.com
      port: 5514
      protocol: tcp
  layer2:
    name: ''
    address: 52:54:00:8d:be:fe
host:
  kickstart:
    baseurl: http://mirror.centos.org/centos/7.4.1708/os/x86_64/
  pxelinux:
    kernel: "/boot/CentOS-7.4.1708-x86_64/vmlinuz"
    config: CentOS-7.4.1708-x86_64
system:
  os: CentOS-7.4.1708-x86_64
  role:
  - ''
  name: vmhost

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install.

Contributing

We are happy to accept contributions in the form of issues and pull requests on GitHub. Please follow these guidelines to make the experience as smooth as possible:

• All development takes place in feature branches, with master only accepting non-fast-forward merges.

• Others shall be able to use the Pallet Jack library to build their own tools. To facilitate this, the library and the included tools are packaged as two different Ruby gems, and are intended to be loosely coupled. If you introduce API changes, please increment version numbers according to semantic versioning.

• All code will be reviewed before it is merged. To help the reviewer, send your work as a series of logically separate changes, not as one gigantic squash commit. Make sure bisection will work by ensuring the code actually works after each change.

• GnuPG sign all your commits and tags, with a key that is validated by GitHub.

  • GitHub's web UI cannot generate signed merges when accepting pull requests. Instead, we use a custom tool to accept them. You can still send them through the web as usual.

  • Your code shall be signed by you. Therefore, the maintainer cannot fix any merge conflicts arising from your pull request. If there are any conflicts, please rebase onto current master before sending your pull request.

• Document your work.

  • At an absolute minimum, Ruby code shall have RDoc blocks documenting each function, with analogues for other languages (e.g. Python docstrings).

  • User-visible features shall have examples in the examples/ directory. In particular, the example warehouse shall include demonstrations of all keys used by any included tool.

    • If your code needs larger chunks of static data to work, please provide it in a separate directory under examples/. See e.g. the examples/pxelinux/ tree, which contains files required to make sense of the output from palletjack2pxelinux.

  • Write your commit messages in the usual Git style: a short summary in the first line, then paragraphs of explanatory text, line wrapped.

  • For externally visible changes (either to users or tool developers), add a note in the changelog.

• Test your code.

  • Code shall pass Rubocop tests. See .rubocop.yml for configured options. Rubocop is automaticallly run with the default Rake task.

  • Tests shall be written in RSpec.

  • Library code shall have unit tests.

  • Tools shall have integration and end-to-end tests.