coredns/plugin/erratic/README.md
Miek Gieben 0353abd3f8
plugin/erratic: linkify RFC references (#1593)
Also add Also See Section.
2018-03-07 13:52:32 +00:00

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# erratic
## Name
*erratic* - a plugin useful for testing client behavior.
## Description
*erratic* returns a static response to all queries, but the responses can be delayed, dropped or truncated.
The *erratic* plugin will respond to every A or AAAA query. For any other type it will return
a SERVFAIL response. The reply for A will return 192.0.2.53 (see [RFC
5737](https://tools.ietf.org/html/rfc5737),
for AAAA it returns 2001:DB8::53 (see [RFC 3849](https://tools.ietf.org/html/rfc3849)).
*erratic* can also be used in conjunction with the *autopath* plugin. This is mostly to aid in
testing.
## Syntax
~~~ txt
erratic {
drop [AMOUNT]
truncate [AMOUNT]
delay [AMOUNT [DURATION]]
}
~~~
* `drop`: drop 1 per **AMOUNT** of queries, the default is 2.
* `truncate`: truncate 1 per **AMOUNT** of queries, the default is 2.
* `delay`: delay 1 per **AMOUNT** of queries for **DURATION**, the default for **AMOUNT** is 2 and
the default for **DURATION** is 100ms.
## Health
This plugin implements dynamic health checking. For every dropped query it turns unhealthy.
## Examples
~~~ corefile
. {
erratic {
drop 3
}
}
~~~
Or even shorter if the defaults suits you. Note this only drops queries, it does not delay them.
~~~ corefile
. {
erratic
}
~~~
Delay 1 in 3 queries for 50ms
~~~ corefile
. {
erratic {
delay 3 50ms
}
}
~~~
Delay 1 in 3 and truncate 1 in 5.
~~~ corefile
. {
erratic {
delay 3 5ms
truncate 5
}
}
~~~
Drop every second query.
~~~ corefile
. {
erratic {
drop 2
truncate 2
}
}
~~~
## Also See
[RFC 3849](https://tools.ietf.org/html/rfc3849) and
[RFC 5737](https://tools.ietf.org/html/rfc5737).