zipkin

Zipkin Plugin

This plugin implements the Zipkin http server to gather trace and timing data needed to troubleshoot latency problems in microservice architectures.

Please Note: This plugin is experimental; Its data schema may be subject to change based on its main usage cases and the evolution of the OpenTracing standard.

Configuration:

[[inputs.zipkin]]
    path = "/api/v1/spans" # URL path for span data
    port = 9411 # Port on which Telegraf listens

The plugin accepts spans in JSON or thrift if the Content-Type is application/json or application/x-thrift, respectively. If Content-Type is not set, then the plugin assumes it is JSON format.

Tracing:

This plugin uses Annotations tags and fields to track data from spans

• TRACE: is a set of spans that share a single root span. Traces are built by collecting all Spans that share a traceId.

• SPAN: is a set of Annotations and BinaryAnnotations that correspond to a particular RPC.

• Annotations: for each annotation & binary annotation of a span a metric is output. Records an occurrence in time at the beginning and end of a request.

  Annotations may have the following values:

  • CS (client start): beginning of span, request is made.
  • SR (server receive): server receives request and will start processing it network latency & clock jitters differ it from cs
  • SS (server send): server is done processing and sends request back to client amount of time it took to process request will differ it from sr
  • CR (client receive): end of span, client receives response from server RPC is considered complete with this annotation

Tags

• "id": The 64 bit ID of the span.
• "parent_id": An ID associated with a particular child span. If there is no child span, the parent ID is set to ID.
• "trace_id": The 64 or 128-bit ID of a particular trace. Every span in a trace shares this ID. Concatenation of high and low and converted to hexadecimal.
• "name": Defines a span

Annotations have these additional tags:

• "service_name": Defines a service
• "annotation": The value of an annotation
• "endpoint_host": Listening port concat with IPV4, if port is not present it will not be concatenated

Binary Annotations have these additional tag:

• "service_name": Defines a service
• "annotation": The value of an annotation
• "endpoint_host": Listening port concat with IPV4, if port is not present it will not be concatenated
• "annotation_key": label describing the annotation

Fields:

• "duration_ns": The time in nanoseconds between the end and beginning of a span.

Sample Queries:

Get All Span Names for Service my_web_server

SHOW TAG VALUES FROM "zipkin" with key="name" WHERE "service_name" = 'my_web_server'

• Description: returns a list containing the names of the spans which have annotations with the given service_name of my_web_server.

Get All Service Names

SHOW TAG VALUES FROM "zipkin" WITH KEY = "service_name"

• Description: returns a list of all distinct endpoint service names.

Find spans with longest duration

SELECT max("duration_ns") FROM "zipkin" WHERE "service_name" = 'my_service' AND "name" = 'my_span_name' AND time > now() - 20m GROUP BY "trace_id",time(30s) LIMIT 5

• Description: In the last 20 minutes find the top 5 longest span durations for service my_server and span name my_span_name

Recommended InfluxDB setup

This test will create high cardinality data so we reccomend using the tsi influxDB engine.

How To Set Up InfluxDB For Work With Zipkin

Steps

1. Update InfluxDB to >= 1.3, in order to use the new tsi engine.

2. Generate a config file with the following command:

influxd config > /path/for/config/file

3. Add the following to your config file, under the [data] tab:

[data]
  index-version = "tsi1"

4. Start influxd with your new config file:

influxd -config=/path/to/your/config/file

5. Update your retention policy:

ALTER RETENTION POLICY "autogen" ON "telegraf" DURATION 1d SHARD DURATION 30m

Example Input Trace:

• Cli microservice with two services Test
• Test data from distributed trace repo sample json

Trace Example from Zipkin model

{
  "traceId": "bd7a977555f6b982",
  "name": "query",
  "id": "be2d01e33cc78d97",
  "parentId": "ebf33e1a81dc6f71",
  "timestamp": 1458702548786000,
  "duration": 13000,
  "annotations": [
    {
      "endpoint": {
        "serviceName": "zipkin-query",
        "ipv4": "192.168.1.2",
        "port": 9411
      },
      "timestamp": 1458702548786000,
      "value": "cs"
    },
    {
      "endpoint": {
        "serviceName": "zipkin-query",
        "ipv4": "192.168.1.2",
        "port": 9411
      },
      "timestamp": 1458702548799000,
      "value": "cr"
    }
  ],
  "binaryAnnotations": [
    {
      "key": "jdbc.query",
      "value": "select distinct `zipkin_spans`.`trace_id` from `zipkin_spans` join `zipkin_annotations` on (`zipkin_spans`.`trace_id` = `zipkin_annotations`.`trace_id` and `zipkin_spans`.`id` = `zipkin_annotations`.`span_id`) where (`zipkin_annotations`.`endpoint_service_name` = ? and `zipkin_spans`.`start_ts` between ? and ?) order by `zipkin_spans`.`start_ts` desc limit ?",
      "endpoint": {
        "serviceName": "zipkin-query",
        "ipv4": "192.168.1.2",
        "port": 9411
      }
    },
    {
      "key": "sa",
      "value": true,
      "endpoint": {
        "serviceName": "spanstore-jdbc",
        "ipv4": "127.0.0.1",
        "port": 3306
      }
    }
  ]
}