Update content/en/blog/_posts/2021-09-03-api-server-tracing.md

Signed-off-by: Benedikt Bongartz <[email protected]>

Author: frzifus

content/en/blog/_posts/2021-09-03-api-server-tracing.md

@@ -42,7 +42,11 @@ samplingRatePerMillion: 10000
 
 ### Enabling Etcd Tracing
 
-Add `--experimental-enable-distributed-tracing`,  `--experimental-distributed-tracing-address=0.0.0.0:4317`, `--experimental-distributed-tracing-service-name=etcd` flags to etcd to enable tracing.  Note that this traces every request, so it will probably generate a lot of traces if you enable it. Required etcd version is [v3.5+](https://etcd.io/docs/v3.5/op-guide/monitoring/#distributed-tracing).
+Add `--experimental-enable-distributed-tracing`,  `--experimental-distributed-tracing-address=0.0.0.0:4317`, `--experimental-distributed-tracing-service-name=etcd` flags to etcd to enable tracing.  Note that this traces every request, so it will probably generate a lot of traces if you enable it. Required etcd version is [3.5 up to 3.5.4](https://etcd.io/docs/v3.5/op-guide/monitoring/#distributed-tracing).
+
+Starting from version 3.5.5 until version 3.5.10, the default sampling rate for traces is set to 0%, meaning no traces were collected by default. Unfortunately, there is no option provided to configure a higher sampling rate. ([See details](https://github.com/etcd-io/etcd/pull/16951)) 
+
+In version [3.5.11](https://github.com/etcd-io/etcd/blob/main/CHANGELOG/CHANGELOG-3.5.md#v3511-2023-12-07), the number of samples to collect per million spans can be configured using the newly introduced `--experimental-distributed-tracing-sampling-rate=1000000` flag.
 
 ### Example Trace: List Nodes