Introduction

This project has as a goal to provide a service to store at a central place key-value pairs, that can be used by loosely connected, but related servers.

These servers will have some kind of hierarchy, which can be administered in the tool. This means that elements that are the same for multiple servers only have to be defined once.

The remote servers will obtain acces by using a rest interface. Modifications can be made either via a web interface.

The rest interface will support multiple output formats e.g. Yaml, json

Framework

The whole service will be developed using the Django framework, version 1.4. This will give the most flexibility as it will handle a lot of webapp related setup. (And Python is a lot of fun ;) )

Example

The tool works best if an reverse dns tree is used as hierarchie. Using such an setup means that it becomes simple to support puppet, as nodes will be passed via the hiera plugin as a fqdn of the host. If we have an hierarchical store like the example below:

nl
  key0 - value0
  vanbommelonline
    key1 - value1
  sidn
    key2 - value2

• A get call to http://<hostname>/nl will retrieve key0 - value0
• A get call to http://<hostname>/nl/vanbommelonline will retrieve key0 - value0 and key1 - value1
• A get call to http://<hostname>/nl/sidn will retrieve key0 - value0 and key2 - value2
• A get call to http://<hostname>/nl/key2 will retrieve nothing

Remember that key0, key1 and key2 in the above example have to be unique!. But it is possible to connect an key-value pair to multiple locations in the hierarchy

Extending the above example with www gives the following options

nl
  key0 - value0
  vanbommelonline
    key1 - value1
    www
      key0 - value0
  sidn
    key2 - value2

Now requesting key0 (or all key's) from www will only return the value as specified by this child! So it is possible to set global settings while overriding them locally. The webinterface will make this clear.

Example curl usage

One easy way to test this, is by using curl. The following example(s) can be used to query the data. The below example can be copy and pasted to a console when an instance is running and curl is available.

Add the example manually using the webinterface, and then execute the commands below on the commandline.

# And retrieve this data
curl -v --header "Accept: application/json" \
 http://localhost:8000/store/nl/vanbommelonline
curl -v --header "Accept: application/yaml" \
 http://localhost:8000/store/nl/vanbommelonline

Puppet integration

This project is combined with a hiera compatible backend. This backend which will allow intergration between puppet and central_property can be found on github https://github.com/woutervb/hiera-central_property.

To use the puppet integration it is required that the full fqdn (reversed) hierachy is used (up to the point that is required for host specific definitions)

License

This project is licensed under GPLv2.