kumomta/docs/reference/kumo/define_egress_pool.md

kumo.define_egress_pool { PARAMS }

Defines an egress pool, which is a collection of weighted egress sources associated with the source of outbound traffic from the MTA.

This function should be called only from inside your init event handler.

PARAMS is a lua table which may have the following keys:

name

Required string.

The name of the pool. This name can be referenced via make_queue_config().egress_pool.

entries

Required list of entries.

Each entry has a name, which must refer to an source that has been defined via define_egress_source, and an optional weight:

kumo.on('init', function()
  kumo.define_egress_source {
    name = 'ip-1',
    source_address = '10.0.0.1',
  }
  kumo.define_egress_source {
    name = 'ip-2',
    source_address = '10.0.0.2',
  }
  kumo.define_egress_source {
    name = 'ip-3',
    source_address = '10.0.0.3',
  }

  kumo.define_egress_pool {
    name = 'BestReputation',
    entries = {
      { name = 'ip-1' },
    },
  }

  kumo.define_egress_pool {
    name = 'MediumReputation',
    entries = {
      { name = 'ip-2', weight = 2 },
      -- we're warming up ip-3, so use it less frequently than ip-2
      { name = 'ip-3', weight = 1 },
    },
  }
end)

The weight is used as part of Weighted Round-Robin selection for the source from the pool.

If the weights are all equal, or are all left unspecified, then simple round-robin selection of sources will occur.

Otherwise, the weight influences how often a given source will be used for traffic originating from this pool.

A weight of 0 is permitted: it is equivalent to not including the associated sources in the list of entries.

If weight is left unspecified, it defaults to 1.