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Version: 31.0.0

a9s Prometheus SPI Configuration

This document describes a9s Prometheus SPI configuration.

Custom Parameter Configuration

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

The a9s Prometheus 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 Prometheus SPI configuration. The platform operator has to configure the property prometheus-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:

prometheus-spi:
service_instance:
custom_param_config:
mapping_strict_match:
default_value: true
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.

NameDefault valueIs modifiable
mapping_strict_matchtruetrue

mapping_strict_match

This property is used to allow only the metrics specified in the Graphite mapping configuration. Therefore, If you have a very large set of metrics you may want to skip the ones that don't match the mapping configuration. Graphite Documentation

Example Configuration

The following is an example for the default custom parameter configuration.

The default value for the custom parameter mapping_strict_match should be true. Additionally, the application developer should not be allowed to set mapping_strict_match.

Then the configuration must look the following way:

prometheus-spi:
service_instance:
custom_param_config:
mapping_strict_match:
default_value: true
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 know 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.