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• Create a znode (or modify existing) under the required path with the configs that you want to update. Example, if you want to change quotas for producer "Adi", add a path under /config/producers/Adi as show shown below.
• Create a sequential znode under "config/changes/config_change_XX". This will send a notification to all the watchers. The data within the change node should indicate what has changed i.e. topic config + topic name, client config + clientId or broker config + brokerId.
• The brokers process the changed configs.

Modeling Default values

In addition to topic/client/broker level overrides, we also need a mechanism to model default configuration. For example: say we have default quotas for all clients and we need to selectively override them on a per-client basis. The above approach doesnSo far, we don't provide have a way to specify change the the default values. We cacan do this by having a special path to store defaults.

The properties in this znode are applicable to all clients, topics and brokers respectively. Changing something here should affect all entities unless overridden explicitly.
 
/config/producers/__default
/config/consumers/__default
/config/topics/__default
/config/brokers/__default
 
Let's extend the example of quotas. Assume that we have a default quota of 5Mbytes per second per producer and we want to change it to 10M for the producer Adi. The default znode will look like this:
/config/producers/__default
{"version": 0, "config" : {quota=5M}

Overridden config:
/config/producers/Adi
{"version": 0, "config" : {quota=10M}

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