OpenTracing

启用NGINX服务的请求，以通过OpenTracing项目进行分布式跟踪.

使用第三方模块 opentracing-contrib/nginx-opentracing nginx ingress controller可以将NGINX配置为启用 OpenTracing 检测。默认情况下，此功能处于禁用状态。

Usage

要启用检测，我们必须在配置ConfigMap中启用OpenTracing

data:
  enable-opentracing: "true"

我们还必须设置上传跟踪时要使用的主机:

zipkin-collector-host: zipkin.default.svc.cluster.local
jaeger-collector-host: jaeger-agent.default.svc.cluster.local
datadog-collector-host: datadog-agent.default.svc.cluster.local

注意:在调用该选项 jaeger-collector-host时, 您需要将其指向 jaeger-agent, 而不是 jaeger-collector 组件.

接下来，您将需要部署一个使用OpenTracing的分布式跟踪系统. Zipkin and Jaeger and Datadog have been tested.

其他可选配置选项:

# specifies the port to use when uploading traces, Default: 9411
zipkin-collector-port

# specifies the service name to use for any traces created, Default: nginx
zipkin-service-name

# specifies sample rate for any traces created, Default: 1.0
zipkin-sample-rate

# specifies the port to use when uploading traces, Default: 6831
jaeger-collector-port

# specifies the service name to use for any traces created, Default: nginx
jaeger-service-name

# specifies the sampler to be used when sampling traces.
# The available samplers are: const, probabilistic, ratelimiting, remote, Default: const
jaeger-sampler-type

# specifies the argument to be passed to the sampler constructor, Default: 1
jaeger-sampler-param

# Specifies the custom remote sampler host to be passed to the sampler constructor. Must be a valid URL.
# Default: http://127.0.0.1
jaeger-sampler-host

# Specifies the custom remote sampler port to be passed to the sampler constructor. Must be a number. Default: 5778
jaeger-sampler-port

# Specifies the header name used for passing trace context. Must be a string. Default: uber-trace-id
jaeger-trace-context-header-name

# Specifies the header name used for force sampling. Must be a string. Default: jaeger-debug-id
jaeger-debug-header

# Specifies the header name used to submit baggage if there is no root span. Must be a string. Default: jaeger-baggage
jaeger-baggage-header

# Specifies the header prefix used to propagate baggage. Must be a string. Default: uberctx-
jaeger-tracer-baggage-header-prefix

# specifies the port to use when uploading traces, Default 8126
datadog-collector-port

# specifies the service name to use for any traces created, Default: nginx
datadog-service-name

# specifies the operation name to use for any traces collected, Default: nginx.handle
datadog-operation-name-override

All these options (including host) allow environment variables, such as $HOSTNAME or $HOST_IP. In the case of Jaeger, if you have a Jaeger agent running on each machine in your cluster, you can use something like $HOST_IP (which can be 'mounted' with the status.hostIP fieldpath, as described here) to make sure traces will be sent to the local agent.

Examples

The following examples show how to deploy and test different distributed tracing systems. These example can be performed using Minikube.

Zipkin

In the rnburn/zipkin-date-server GitHub repository is an example of a dockerized date service. To install the example and Zipkin collector run:

kubectl create -f https://raw.githubusercontent.com/rnburn/zipkin-date-server/master/kubernetes/zipkin.yaml
kubectl create -f https://raw.githubusercontent.com/rnburn/zipkin-date-server/master/kubernetes/deployment.yaml

Also we need to configure the nginx controller ConfigMap with the required values:

$ echo '
apiVersion: v1
kind: ConfigMap
data:
  enable-opentracing: "true"
  zipkin-collector-host: zipkin.default.svc.cluster.local
metadata:
  name: nginx-configuration
  namespace: kube-system
' | kubectl replace -f -

In the Zipkin interface we can see the details:

Jaeger

1. Enable Ingress addon in Minikube:

    $ minikube addons enable ingress

2. Add Minikube IP to /etc/hosts:

    $ echo "$(minikube ip) example.com" | sudo tee -a /etc/hosts

3. Apply a basic Service and Ingress Resource:

    # Create Echoheaders Deployment
    $ kubectl run echoheaders --image=k8s.gcr.io/echoserver:1.4 --replicas=1 --port=8080
   
    # Expose as a Cluster-IP
    $ kubectl expose deployment echoheaders --port=80 --target-port=8080 --name=echoheaders-x
   
    # Apply the Ingress Resource
    $ echo '
      apiVersion: extensions/v1beta1
      kind: Ingress
      metadata:
        name: echo-ingress
      spec:
        rules:
        - host: example.com
          http:
            paths:
            - backend:
                serviceName: echoheaders-x
                servicePort: 80
              path: /echo
      ' | kubectl apply -f -

4. Enable OpenTracing and set the jaeger-collector-host:

    $ echo '
      apiVersion: v1
      kind: ConfigMap
      data:
        enable-opentracing: "true"
        jaeger-collector-host: jaeger-agent.default.svc.cluster.local
      metadata:
        name: nginx-configuration
        namespace: kube-system
      ' | kubectl replace -f -

5. Apply the Jaeger All-In-One Template:

    $ kubectl apply -f https://raw.githubusercontent.com/jaegertracing/jaeger-kubernetes/master/all-in-one/jaeger-all-in-one-template.yml

6. Make a few requests to the Service:

    $ curl example.com/echo -d "meow"
   
    CLIENT VALUES:
    client_address=172.17.0.5
    command=POST
    real path=/echo
    query=nil
    request_version=1.1
    request_uri=http://example.com:8080/echo
   
    SERVER VALUES:
    server_version=nginx: 1.10.0 - lua: 10001
   
    HEADERS RECEIVED:
    accept=*/*
    connection=close
    content-length=4
    content-type=application/x-www-form-urlencoded
    host=example.com
    user-agent=curl/7.54.0
    x-forwarded-for=192.168.99.1
    x-forwarded-host=example.com
    x-forwarded-port=80
    x-forwarded-proto=http
    x-original-uri=/echo
    x-real-ip=192.168.99.1
    x-scheme=http
    BODY:
    meow

7. View the Jaeger UI:

    $ minikube service jaeger-query --url
   
    http://192.168.99.100:30183

   In the Jaeger interface we can see the details: