a9s Elasticsearch SPI Configuration

This document describes a9s Elasticsearch SPI configuration.

Custom Parameter Configuration

The a9s Elasticsearch SPI handles custom parameters for all service instances. It does configuration and validation of custom parameters.

The a9s Elasticsearch SPI defines default values for certain custom parameters. Also, it defines whether a custom parameter can be set by the application developer.

The platform operator can overwrite those choices by changing the a9s Elasticsearch SPI configuration. The platform operator has to configure the property elasticsearch-spi.service_instance.custom_param_config. The property value must be a hash. Every key in that hash stands for a custom parameter and the value for every key contains the configuration for that particular parameter. The configuration for a particular param is a hash consisting of the following optional keys: default_value and modifiable. The key default_value specifies the default value for that parameter and modifiable specifies whether the application developer is allowed to set that custom parameter. For example:

elasticsearch-spi:
  service_instance:
    custom_param_config:
      ssl_session_timeout:
        default_value: 24h
        modifiable: true

Default Custom Parameter Configuration

The following table contains custom parameters that are configurable by the platform operator. The meaning of those custom parameters can be found below.

Name	Default value	Is modifiable
ssl_session_timeout	24h	true

Example Configuration

Let's build an imaginary example.

The default value for the custom parameter ssl_session_timeout should be 24h. Additionally, the application developer should not be allowed allowed to set ssl_session_timeout.

Then the configuration must look the following way:

elasticsearch-spi:
  service_instance:
    custom_param_config:
      ssl_session_timeout:
        default_value: 24h
        modifiable: false

Per Plan Configuration

Take a look at Service Plans documentation if you want to configure the custom parameters per plan.

Notes

Additional custom parameters will be made available over time. We do not make all available custom parameters the SPIs knows available to the platform operator from the beginning.

During the SPI startup, the configuration the platform operator made will be checked. When it's invalid, the SPI will not start up.