prudentia 0.6

Mission

Prudentia’s mission is to help you to get production (or any other environment) ready in minutes instead of days, through streamlining all the actions needed to provision your architectural components.

Features

Prudentia uses Ansible as main automation system, so it easily understand playbooks. A playbook is one of the information needed to define a Prudentia Box.

Prudentia currently offers:

• A CLI (supporting auto-completion) used to interactively define Boxes and run operation on them

• Here-Document format to script Prudentia environments

• Provision existing server that can be accessed trough SSH

• Manage the lifecycle of a Box that has been created through Prudentia

• Create Boxes using one of the available providers

  • Vagrant

  • DigitalOcean

  • Local

  • Ssh

Currently, all features work with Python 2.6 and 2.7. Work is under way to support Python 3.3+ in the same codebase.

Installation

To install prudentia:

$ pip install prudentia

It may be necessary to have root privileges, in which case:

$ sudo pip install prudentia

To uninstall:

$ pip uninstall prudentia

Box operations

Simple providers (e.g. Local provider or SSH provider) supports the following operations:

• register: adds a new box definition to the registry

• unregister: removes a box from the registry

• reconfigure: changes the definition of an existing box

• list: lists all box in the registry

• set: defines or override a playbook variable

• unset: removes variable

• provision: runs tasks defined in the playbook associated with a box

Factory providers (e.g. Vagrant provider or DigitalOcean provider) extend simple providers and allow you to change the life cycle of a box:

• create: instantiate a new instance based of the box definition

• restart: reloads the instance

• stop: shuts down the instance

• destroy: kill the instance

• phoenix: shortcut for stop -> destroy -> create -> start -> provision (refers to the phoenix server)

Usage

We’ll show a usage example of the SSH provider bundled with Prudentia.

Make sure you have a server that you can ssh onto.

$ prudentia ssh

Check what the SSH provider can do using tab completion:

(Prudentia > Ssh)
EOF          help         list         provision    reconfigure  register     set          unregister   unset

Let’s start registering a new box:

(Prudentia > Ssh) register
Specify the playbook path:

Now Prudentia is asking for a playbook path, and this is actually an Ansible playbook.

You can use one of the samples that you can find in the examples/boxes directory. For instance the tasks.yml that will run some Ansible tasks that we’ve defined (those tasks are not that meaningful but they are used as sanity check in our tests).

So let’s continue using the tasks.yml:

(Prudentia > Ssh) register
Specify the playbook path: /path/to/prudentia/examples/boxes/tasks.yml
Specify the box name [default: tasks-host]:
Specify the address of the instance: ip.of.your.server
Specify the remote user [default: _your_user_]:
Specify the password for the remote user [default: ssh key]:

Box example -> (/path/to/prudentia/examples/boxes/tasks.yml, tasks-host, ip.of.your.server, _your_user_) added.

You will notice for some questions Prudentia gives us a suggested answer within [ ]. For instance the Box name is been suggested as tasks-host, if you like the suggestion just press enter to choose it.

So far we’ve registered a Prudentia Box that can be used to play around. If you want to check again the definition of it:

(Prudentia > Ssh) list
example -> (/path/to/prudentia/examples/boxes/tasks.yml, tasks-host, ip.of.your.server, _your_user_)

Now that we have double checked that our Box has been registered, we can provision it:

(Prudentia > Ssh) provision example

PLAY [tasks-host] ***************************************************************

GATHERING FACTS ***************************************************************
ok: [tasks-host]

TASK: [Uname] *****************************************************************
changed: [tasks-host] => {"changed": true, "cmd": ["uname", "-a"], "delta": "0:00:00.005527", "end": "2015-01-01 19:13:58.633534", "rc": 0, "start": "2015-01-01 19:13:58.628007", "stderr": "", "stdout": "Darwin tiziano-air 12.5.0 Darwin Kernel Version 12.5.0: Sun Sep 29 13:33:47 PDT 2013; root:xnu-2050.48.12~1/RELEASE_X86_64 x86_64", "warnings": []}

TASK: [Shuffle] ***************************************************************
ok: [tasks-host] => (item=2) => {
    "item": 2,
    "msg": "2"
}
ok: [tasks-host] => (item=4) => {
    "item": 4,
    "msg": "4"
}
ok: [tasks-host] => (item=1) => {
    "item": 1,
    "msg": "1"
}
ok: [tasks-host] => (item=5) => {
    "item": 5,
    "msg": "5"
}
ok: [tasks-host] => (item=3) => {
    "item": 3,
    "msg": "3"
}

TASK: [No operation] **********************************************************
ok: [tasks-host] => {
    "msg": "Task noop executed."
}

PLAY RECAP ********************************************************************
tasks-host                  : ok=4    changed=1    unreachable=0    failed=0

Play run took 0 minutes

Now Prudentia has done the reasonable uninteresting uname, shuffling a list of ints and noop tasks for me on the remote machine.

The same sequence of operations can be executed using the Here-Document input:

$ prudentia ssh <<EOF
register
/path/to/prudentia/examples/boxes/tasks.yml
tasks-host
ip.of.your.server
_your_user_

provision tasks-host
EOF

This is the easiest example I could come up with to show you the use of the SSH provider bundled in Prudentia.

I invite you to checkout the other providers.

More Info

Here you can find a guide on how to use Prudentia to provision a Digital Ocean droplet with the StarterSquad website on it.

Another important source of information is Iwein’s post that gives you an idea of what Continuous Delivery is and where Prudentia fits into the flow.

Questions & Contributions

Questions, Contributions and Feedback are more than welcome.

You can checkout planned new features on the Trello Board. Feel free to create feature requests on github issues.

You can e-mail me at:

tiziano@startersquad.com