loki Runtime Configuration file

Loki has a concept of “runtime config” file, which is simply a file that is reloaded while Loki is running. It is used by some Loki components to allow operator to change some aspects of Loki configuration without restarting it. File is specified by using -runtime-config.file= flag and reload period (which defaults to 10 seconds) can be changed by -runtime-config.reload-period= flag. Previously this mechanism was only used by limits overrides, and flags were called -limits.per-user-override-config= and -limits.per-user-override-period=10s respectively. These are still used, if -runtime-config.file= is not specified.

At the moment, two components use runtime configuration: limits and multi KV store.

Options for runtime configuration reload can also be configured via YAML:

# Configuration file to periodically check and reload.
[file: : default = empty]

# How often to check the file.
[period: : default 10s]

Example runtime configuration file:

overrides:
  tenant1:
    ingestion_rate_mb: 10
    max_streams_per_user: 100000
    max_chunks_per_query: 100000
  tenant2:
    max_streams_per_user: 1000000
    max_chunks_per_query: 1000000

multi_kv_config:
    mirror-enabled: false
    primary: consul