druid/docs/content/Rule-Configuration.md

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layout: doc_page
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# Configuring Rules for Coordinator Nodes
Note: It is recommended that the coordinator console is used to configure rules. However, the coordinator node does have HTTP endpoints to programmatically configure rules.

Load Rules
----------

Load rules indicate how many replicants of a segment should exist in a server tier.

### Interval Load Rule

Interval load rules are of the form:

```json
{
  "type" : "loadByInterval",
  "interval" : "2012-01-01/2013-01-01",
  "tier" : "hot"
}
```

* `type` - this should always be "loadByInterval"
* `interval` - A JSON Object representing ISO-8601 Intervals
* `tier` - the configured historical node tier

### Period Load Rule

Period load rules are of the form:

```json
{
  "type" : "loadByPeriod",
  "period" : "P1M",
  "tier" : "hot"
}
```

* `type` - this should always be "loadByPeriod"
* `period` - A JSON Object representing ISO-8601 Periods
* `tier` - the configured historical node tier

The interval of a segment will be compared against the specified period. The rule matches if the period overlaps the interval.

Drop Rules
----------

Drop rules indicate when segments should be dropped from the cluster.

### Interval Drop Rule

Interval drop rules are of the form:

```json
{
  "type" : "dropByInterval",
  "interval" : "2012-01-01/2013-01-01"
}
```

* `type` - this should always be "dropByInterval"
* `interval` - A JSON Object representing ISO-8601 Periods

A segment is dropped if the interval contains the interval of the segment.

### Period Drop Rule

Period drop rules are of the form:

```json
{
  "type" : "dropByPeriod",
  "period" : "P1M"
}
```

* `type` - this should always be "dropByPeriod"
* `period` - A JSON Object representing ISO-8601 Periods

The interval of a segment will be compared against the specified period. The period is from some time in the past to the current time. The rule matches if the period contains the interval.