Heron clusters can be configured at two levels:
- The system level — System-level configurations apply to the whole Heron cluster rather than to any specific component (e.g. logging configurations).
- The component level — Component-level configurations enable you to establish default configurations for different components. These configurations are fixed at any stage of the topology’s lifecycle, once the topology is deployed.
Neither system- nor component-level configurations can be overridden by topology developers.
All system-level configs and component-level defaults are declared in a
YAML config file in
in the Heron codebase. You can leave that file as is when compiling
Heron or modify the values to suit your use
The System Level
There are a small handful of system-level configs for Heron. These are detailed in System-level Configuration.
The Component Level
There is a wide variety of component-level configurations that you can establish as defaults in your Heron cluster. These configurations tend to apply to specific components in a topology and are detailed in the docs below:
Overriding Heron Cluster Configuration
The Heron configuration applies globally to a cluster. It is discouraged to modify the configuration to suit one topology. It is not possible to override the Heron configuration for a topology via Heron client or other Heron tools.
More on Heron’s CLI tool can be found in Managing Heron Topologies.