Hydrolix Tunables

Tunables overview

Hydrolix uses tunables, a set of YAML key-value pairs, to configure Hydrolix cluster and secrets behavior, referred to as Hydrolix tunables.

In version 5.0, Hydrolix added the Hydrolix Tunable Names (HTN) naming convention to give a more granular level of control over cluster behavior. These HTN tunables work in conjunction with the existing Hydrolix tunables.

Hydrolix defines all tunables in the hydrolixcluster.yaml file, under spec:.

Hydrolix tunables

Hydrolix tunables are used to provide global Hydrolix cluster control, and affect all levels of the cluster. See the Hydrolix Tunables List for more information.

Examples of Hydrolix tunables

• decay_reap_batch_size
• http_response_timeout_ms
• prometheus_scrape_interval

HTN tunables

HTN tunables can be set at different levels: service, pool, and container. The HTN convention provides a clear naming structure and fine control over cluster behavior.

Format structure for HTN tunables

HTN tunables follow a specific naming convention:

htn:tunable_name:service_name:pool_name:container_name: value

The key components for each HTN tunable are:

• htn: Prefix indicates the tunable uses the HTN naming structure
• tunable_name: The tunable parameter name
• value: The tunable value
• service_name: (Optional) The service where the tunable is applied, can be omitted by using an empty string
• pool_name: (Optional) The pool in the service, can be left empty
• container_name: (Optional) The specific container in the pool and service, can be left empty

Tunable precedence order

HTN tunables take precedence over Hydrolix tunables. If no HTN tunable exists in the hydrolixcluster.yaml file, Hydrolix uses the non-HTN tunable. If neither an HTN or Hydrolix tunable exists, Hydrolix uses the system default.