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Version: Develop

a9s Redis® SPI Configuration

This document describes a9s Redis®* SPI configuration.

Custom Parameter Configuration​

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

The a9s Redis® 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 Redis® SPI configuration. The platform operator has to configure the property redis-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:

redis-spi:
  service_instance:
    custom_param_config:
      maxclients:
        default_value: 6000
        modifiable: false

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 read in the application developer documentation for a9s Redis®.

NameDefault valueIs modifiableVersion Compatibility
lazyfree-lazy-eviction'no'trueall
lazyfree-lazy-expire'no'trueall
lua-time-limit5000trueall
maxclients10000trueall
maxmemory-policy'volatile-lru'trueall
maxmemory-samples5trueall
notify-keyspace-events''trueall
failover-timeout30000trueall
down-after-milliseconds10000trueall
stop-cluster-update-on-failuretruefalseall
cluster-update-node-timeout10falseall
tls-protocolsnulltrueall
tls-ciphersnulltrueall
tls-ciphersuitesnulltrueall
hostname-resolution'disabled'true>= 7

tls-protocols​

The parameter tls-protocols corresponds to the Redis® configuration parameter tls-protocols.

tls-ciphers​

The parameter tls-ciphers corresponds to the Redis® configuration parameter tls-ciphers. This parameter sets the list of ciphers used for TLS 1.2 and below.

a9s Redis® SPI does no validation for the tls-ciphers value except that it must be of type string or null (do not set tls-ciphers in redis.conf and sentinel.conf).

tls-ciphersuites​

The parameter tls-ciphersuites corresponds to the Redis® configuration parameter tls-ciphersuites. This parameter sets the list of ciphers used for TLS 1.3 and above.

a9s Redis® SPI does no validation for the tls-ciphersuites value except that it must be of type string or null (do not set tls-ciphers in redis.conf and sentinel.conf).

hostname-resolution​

For more information, refer to the hostname-resolution section of the Application Developer's documentation.

Example Configuration​

Let's build an imaginary example.

The default value for the maxclients custom parameter should be 600. The custom parameter lua-time-limit should also have a default value of 600 and the application developer should not be allowed to change it.

Then the configuration must look the following way:

redis-spi:
  service_instance:
    custom_param_config:
      maxclients:
        default_value: 600
        modifiable: true
      lua-time-limit:
        default_value: 600
        modifiable: false
      failover-timeout:
        default_value: 30000
        modifiable: true
      down-after-milliseconds:
        default_value: 10000
        modifiable: true

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.

redis-spi.protocols​

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

*Redis is a registered trademark of Redis Ltd. Any rights therein are reserved to Redis Ltd. Any use by anynines GmbH is for referential purposes only and does not indicate any sponsorship, endorsement or affiliation between Redis and anynines GmbH.