<p>My question about Istio in Kubernetes. I have Istio sample rate of 1% and I have error which is not included in 1%. Would I see in Jaeger trace for this error?</p>

<p>I kind of new to Kubernetes and Istio. That's why can't tested on my own. I have been playing with Istio's example of <code>Book Application</code> and I wonder would I see trace with error which not included in 1% of sample rate.</p>

<p>Configure Istio when installing with:</p>

<pre><code>pilot.traceSampling=1
</code></pre>

<p>As result want to know can I see error which not included in sample rate. If no, how I configure Istio to see it if possible?</p>

Serhii Zadorozhnyi
<p>If you have sampling rate set to 1% then error will be seen in Jaeger once it occurs 100 times.
This is mentioned at <a href="https://istio.io/docs/tasks/telemetry/distributed-tracing/jaeger/" rel="nofollow noreferrer">Distributed Tracing - Jaeger</a>:</p>

<blockquote>
  <p>To see trace data, you must send requests to your service. The number of requests depends on Istio’s sampling rate. You set this rate when you install Istio. The default sampling rate is 1%. You need to send at least 100 requests before the first trace is visible. To send a 100 requests to the  <code>productpage</code>  service, use the following command:</p>
  
  <p><code>$ for i in  `seq 1 100`;  do  curl -s -o /dev/null http://$GATEWAY_URL/productpage;  done</code></p>
</blockquote>

<p>If you are not seeing the error in the current sample, I would advice make the sample higher.</p>

<p>You can read about <a href="https://www.envoyproxy.io/docs/envoy/v1.10.0/intro/arch_overview/tracing#trace-context-propagation" rel="nofollow noreferrer">Tracing context propagation</a> which is being done by <a href="https://www.envoyproxy.io/docs/envoy/v1.10.0/" rel="nofollow noreferrer">Envoy</a>.
Envoy automatically sends spans to tracing collectors</p>

<blockquote>
  <p>Alternatively the trace context can be manually propagated by the service:</p>
  
  <ul>
  <li>When using the LightStep tracer, Envoy relies on the service to propagate the  <a href="https://www.envoyproxy.io/docs/envoy/v1.10.0/configuration/http_conn_man/headers#config-http-conn-man-headers-x-ot-span-context" rel="nofollow noreferrer">x-ot-span-context</a>  HTTP header while sending HTTP requests to other services.</li>
  <li>When using the Zipkin tracer, Envoy relies on the service to propagate the B3 HTTP headers (  <a href="https://www.envoyproxy.io/docs/envoy/v1.10.0/configuration/http_conn_man/headers#config-http-conn-man-headers-x-b3-traceid" rel="nofollow noreferrer">x-b3-traceid</a>,  <a href="https://www.envoyproxy.io/docs/envoy/v1.10.0/configuration/http_conn_man/headers#config-http-conn-man-headers-x-b3-spanid" rel="nofollow noreferrer">x-b3-spanid</a>,  <a href="https://www.envoyproxy.io/docs/envoy/v1.10.0/configuration/http_conn_man/headers#config-http-conn-man-headers-x-b3-parentspanid" rel="nofollow noreferrer">x-b3-parentspanid</a>,  <a href="https://www.envoyproxy.io/docs/envoy/v1.10.0/configuration/http_conn_man/headers#config-http-conn-man-headers-x-b3-sampled" rel="nofollow noreferrer">x-b3-sampled</a>, and  <a href="https://www.envoyproxy.io/docs/envoy/v1.10.0/configuration/http_conn_man/headers#config-http-conn-man-headers-x-b3-flags" rel="nofollow noreferrer">x-b3-flags</a>). The  <a href="https://www.envoyproxy.io/docs/envoy/v1.10.0/configuration/http_conn_man/headers#config-http-conn-man-headers-x-b3-sampled" rel="nofollow noreferrer">x-b3-sampled</a>  header can also be supplied by an external client to either enable or disable tracing for a particular request. In addition, the single  <a href="https://www.envoyproxy.io/docs/envoy/v1.10.0/configuration/http_conn_man/headers#config-http-conn-man-headers-b3" rel="nofollow noreferrer">b3</a>  header propagation format is supported, which is a more compressed format.</li>
  <li>When using the Datadog tracer, Envoy relies on the service to propagate the Datadog-specific HTTP headers (  <a href="https://www.envoyproxy.io/docs/envoy/v1.10.0/configuration/http_conn_man/headers#config-http-conn-man-headers-x-datadog-trace-id" rel="nofollow noreferrer">x-datadog-trace-id</a>,  <a href="https://www.envoyproxy.io/docs/envoy/v1.10.0/configuration/http_conn_man/headers#config-http-conn-man-headers-x-datadog-parent-id" rel="nofollow noreferrer">x-datadog-parent-id</a>,  <a href="https://www.envoyproxy.io/docs/envoy/v1.10.0/configuration/http_conn_man/headers#config-http-conn-man-headers-x-datadog-sampling-priority" rel="nofollow noreferrer">x-datadog-sampling-priority</a>).</li>
  </ul>
</blockquote>
