As far as the data model is concerned, we need two types of objects:

• An object for database instances

• An object for database sections

Database sections

For the database sections, we need to store the following information:

• The master database instance

• read-only state (true/false)

• read-only message

• depool threshold (an integer, minimum number of instances pooled)

so our data model will be:

# Key: db_sections/sN

master: <string>

read-only: <boolean>

ro-reason: <string>

min_slaves: <integer>

Database instances

For the database instances, we need the following:

• The hostname to connect to

• The ip corresponding to that hostname

• for each section defined for this instance:

• The pooled status, boolean

• A coefficient between 0 and 1 that will multiply the weights

• The weight in the main group, as an integer

• For each group configured, the relative weight as an integer

so our data model will be:

# key: db_eqiad/instance_label

hostname: <string>

host_ip: <ipaddress>

port: <integer>

sections: 

    - section: sX <should be defined as a section model

      pooled: <boolean>

      weight_multiplier: <integer, between 0 and 1>

      weight: <integer>

      groups:

         - group: <string, fixed values>

            weight: <integer>