pepa 0.7.8

Configuration templating for SaltStack using Hierarchical substitution and Jinja

Pepa

Configuration templating for SaltStack using Hierarchical substitution and Jinja.

Pepa is part of the SaltStack as of release 2014.7.

Quick testing

You can easily test Pepa from the Command Line.

Create a virtual env. and install the required modules.

virtualenv venv
cd venv
source bin/activate
pip install pepa

Clone and run Pepa.

git clone https://github.com/mickep76/pepa.git
cd pepa
pepa -c examples/master test.example.com -d

Test and validate templates.

pepa-test --config examples/master -d

Look at output.

pepa-test --config examples/master -d -s

Install Pepa

git clone https://github.com/mickep76/pepa.git
mkdir -p /srv/salt/ext/pillar
cp pillar/pepa.py /srv/salt/ext/pillar/pepa.py

Configuring Pepa

extension_modules: /srv/salt/ext

ext_pillar:
  - pepa:
      resource: host                # Name of resource directory and sub-key in pillars
      sequence:                     # Sequence used for hierarchical substitution
        - hostname:                 # Name of key
            name: input             # Alias used for template directory
            base_only: True         # Only use templates from Base environment, i.e. no staging
        - default:
        - environment:
        - location..region:
            name: region
        - location..country:
            name: country
        - location..datacenter:
            name: datacenter
        - roles:
        - osfinger:
            name: os
        - hostname:
            name: override
            base_only: True
      subkey: True                  # Create a sub-key in pillars, named after the resource in this case [host]
      subkey_only: True             # Only create a sub-key, and leave the top level untouched

pepa_roots:                         # Base directory for each environment
  base: /srv/pepa/base              # Path for base environment
  dev: /srv/pepa/base               # Associate dev with base
  qa: /srv/pepa/qa
  prod: /srv/pepa/prod

# Use a different delimiter for nested dictionaries, defaults to '..' since some keys may use '.' in the name
#pepa_delimiter: ..

# Supply Grains for Pepa, this should **ONLY** be used for testing or validation
#pepa_grains:
#  environment: dev

# Supply Pillar for Pepa, this should **ONLY** be used for testing or validation
#pepa_pillars:
#  saltversion: 0.17.4

# Enable debug for Pepa, and keep Salt on warning
#log_level: debug

#log_granular_levels:
#  salt: warning
#  salt.loaded.ext.pillar.pepa: debug

Pepa can also be used in Master-less SaltStack setup.

Command line

usage: pepa [-h] [-c CONFIG] [-d] [-g GRAINS] [-p PILLAR] [-n] [-v]
            hostname

positional arguments:
  hostname              Hostname

optional arguments:
  -h, --help            show this help message and exit
  -c CONFIG, --config CONFIG
                        Configuration file
  -r RESOURCE, --resource RESOURCE
                        Resource, defaults to first resource
  -d, --debug           Print debug info
  -g GRAINS, --grains GRAINS
                        Input Grains as YAML
  -p PILLAR, --pillar PILLAR
                        Input Pillar as YAML
  -n, --no-color        No color output
  -v, --validate        Validate output

Templates

Templates is configuration for a host or software, that can use information from Grains or Pillars. These can then be used for hierarchically substitution.

Example File: host/input/test_example_com.yaml

location..region: emea
location..country: nl
location..datacenter: foobar
environment: dev
roles:
  - salt.master
network..gateway: 10.0.0.254
network..interfaces..eth0..hwaddr: 00:20:26:a1:12:12
network..interfaces..eth0..dhcp: False
network..interfaces..eth0..ipv4: 10.0.0.3
network..interfaces..eth0..netmask: 255.255.255.0
network..interfaces..eth0..fqdn: {{ hostname }}
cobbler..profile: fedora-19-x86_64

As you see in this example you can use Jinja directly inside the template.

Example File: host/region/amer.yaml

network..dns..servers:
  - 10.0.0.1
  - 10.0.0.2
time..ntp..servers:
  - ntp1.amer.example.com
  - ntp2.amer.example.com
  - ntp3.amer.example.com
time..timezone: America/Chihuahua
yum..mirror: yum.amer.example.com

Each template is named after the value of the key using lowercase and all extended characters are replaced with underscore.

Example:

osfinger: Fedora-19

Would become:

fedora_19.yaml

Nested dictionaries

In order to create nested dictionaries as output you can use double dot “..” as a delimiter. You can change this using “pepa_delimiter” we choose double dot since single dot is already used by key names in some modules, and using “:” requires quoting in the YAML.

Example:

network..dns..servers:
  - 10.0.0.1
  - 10.0.0.2
network..dns..options:
  - timeout:2
  - attempts:1
  - ndots:1
network..dns..search:
  - example.com

Would become:

network:
  dns:
    servers:
      - 10.0.0.1
      - 10.0.0.2
    options:
      - timeout:2
      - attempts:1
      - ndots:1
    search:
      - example.com

Operators

Operators can be used to merge/unset a list/hash or set the key as immutable, so it can’t be changed.

Operator	Description
merge()	Merge list or hash
unset()	Unset key
immutable()	Set the key as immutable, so it can’t be changed
imerge()	Set immutable and merge
iunset()	Set immutable and unset

Example:

network..dns..search..merge():
  - foobar.com
  - dummy.nl
owner..immutable(): Operations
host..printers..unset():

Testing

Pepa also come’s with a test/validation tool for templates. This allows you to test for valid Jinja/YAML and validate key values.

Command Line

usage: pepa-test [-h] [-c CONFIG] [-r RESOURCE] [-d] [-s] [-t] [-n]

optional arguments:
  -h, --help            show this help message and exit
  -c CONFIG, --config CONFIG
                        Configuration file
  -r RESOURCE, --resource RESOURCE
                        Configuration file, defaults to first resource
  -d, --debug           Print debug info
  -s, --show            Show result of template
  -t, --teamcity        Output validation in TeamCity format
  -n, --no-color        No color output

Test

A test is a set of input values for a template, it’s generally a good idea to create a separate test for each outcome if you have Jinja if statements.

Example: host/default/tests/default-1.yaml

grains..osfinger: Fedora-20
location..region: emea

You can also use Jinja inside a test, for example if you wan’t to iterate through test values.

Schema

A schema is a set of validation rules for each key/value. Schemas use Cerberus module for validation.

Example: host/schemas/pkgrepo.yaml

{% set hostname = '^([a-z0-9]([a-z0-9-]{0,61}[a-z0-9])?\.)+[a-zA-Z]{2,6}$' %}
{% set url = '(http|https?://([-\w\.]+)+(:\d+)?(/([\w/_\.]*(\?\S+)?)?)?)' %}

pkgrepo..mirror:
  type: string
  regex: {{ hostname }}

pkgrepo..type:
  type: string
  allowed: yum

pkgrepo..osabbr:
  type: string
  regex: ^(fc|rhel)[0-9]+$

{% for repo in [ 'base', 'everything', 'updates' ] %}
pkgrepo..repos..{{ repo }}..name:
  type: string
  regex: ^[A-Za-z\ 0-9\-\_]+$

pkgrepo..repos..{{ repo }}..baseurl:
  type: string
  regex: {{ url }}
{% endfor %}

You can also use Jinja inside a schema, for example if you wan’t to iterate through a list of different keys.

You can create complicated datastructures underneth a key, but it’s advisable to split it in several keys using the delimiter for a nested data structures.

Bad

network:
  interfaces:
    eth0:
      ipv4: 192.168.1.2
      netmask: 255.255.255.0

Good

network..interfaces..eth0..ipv4: 192.168.1.2
network..interfaces..eth0..netmask: 255.255.255.0

The first example you can’t properly use substitution and defining the schema becomes more complicated.