COREDNS-TRACE(7)

NAME
trace - enables OpenTracing-based tracing of DNS requests as they go through the plugin chain.

DESCRIPTION
With trace you enable OpenTracing of how a request flows through CoreDNS.

SYNTAX
The simplest form is just:

    trace [ENDPOINT-TYPE] [ENDPOINT]

•   ENDPOINT-TYPE is the type of tracing destination. Currently only zipkin is supported and that is what it defaults to.

•   ENDPOINT is the tracing destination, and defaults to localhost:9411. For Zipkin, if ENDPOINT does not begin with http, then it will be transformed to http://ENDPOINT/api/v1/spans.

With this form, all queries will be traced.

Additional features can be enabled with this syntax:

    trace [ENDPOINT-TYPE] [ENDPOINT] {
        every AMOUNT
        service NAME
        client_server
    }

•   every AMOUNT will only trace one query of each AMOUNT queries. For example, to trace 1 in every 100 queries, use AMOUNT of 100. The default is 1.

•   service NAME allows you to specify the service name reported to the tracing server. Default is coredns.

•   client_server will enable the ClientServerSameSpan OpenTracing feature.

ZIPKIN
You can run Zipkin on a Docker host like this:

    docker run -d -p 9411:9411 openzipkin/zipkin

EXAMPLES
Use an alternative Zipkin address:

    trace tracinghost:9253

or

    . {
        trace zipkin tracinghost:9253
    }

If for some reason you are using an API reverse proxy or something and need to remap the standard Zipkin URL you can do something like:

    trace http://tracinghost:9411/zipkin/api/v1/spans

Trace one query every 10000 queries, rename the service, and enable same span:

    trace tracinghost:9411 {
        every 10000
        service dnsproxy
        client_server
    }