a9s Prometheus SPI Configuration

This document describes a9s Prometheus SPI configuration.

Custom Parameter Configuration

The a9s Prometheus SPI handles custom parameters for all its Service Instances. It configures and validates the 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.

Name	Default value	Is modifiable
mapping_strict_match	true	true
scrape_configs	[]	false

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. For more information see Graphite Documentation.

scrape_configs

This property is used to to configure custom scraping targets for your a9s Prometheus Service Instance. For more information see the Scrape Configs section of the Application Developer.

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.

info

Additional custom parameters will be made available over time. We do not provide all available custom parameters the SPIs allows 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.

prometheus-spi.protocols

For more details on this property, please refer to the a9s Framework TLS configuration documentation.