Add warnings about changing appName

sites/upsun/src/increase-observability/application-metrics/go.md

@@ -65,6 +65,8 @@ defer profiler.Stop()
 
 The `Start` function accepts the following options:
 
+- `WithAppName`: specifies the Application Name.
+
 - `WithCPUDuration`: specifies the length at which to collect CPU profiles.
 The default is 45 seconds. Can also be set via the environment variable `BLACKFIRE_CONPROF_CPU_DURATION`.
 
@@ -85,6 +87,13 @@ If the same parameter is set by both an environment variable and a `Start` call,
 parameter in the `Start` call takes precedence.
 {{% /note %}}
 
+{{< note theme="warning" >}}
+
+On Upsun, `AppName` is set to application name by default. If you override this value via `WithAppName`, you might
+not be able to see it on the profiling tab.
+
+{{< /note >}}
+
 There is also some additional configuration that can be done using environment variables:
 
 - `BLACKFIRE_LOG_FILE`: Sets the log file. The default is logging to `stderr`.

sites/upsun/src/increase-observability/application-metrics/nodejs.md

@@ -72,6 +72,13 @@ The `start` function accepts an object as a parameter with the following keys:
 
 - `uploadTimeoutMillis`: Timeout in milliseconds for the upload request (default: 10000)
 
+{{< note theme="warning" >}}
+
+On Upsun, `appName` is set to application name by default. If you override this value, you might
+not be able to see it on the profiling tab.
+
+{{< /note >}}
+
 ### `function stop() {}`
 
 Stops the continuous profiling probe.
@@ -110,4 +117,4 @@ app.listen(port, () => {
 3. Run the Node.js server
 
 ```bash
-node index.js
+node index.js

sites/upsun/src/increase-observability/application-metrics/python.md

@@ -38,6 +38,13 @@ The Python profiler API (`profiler`) can be initiated with the following options
 - `upload_timeout`: observability data upload timeout. The default is 10 seconds.
 - `labels`: a dict containing the custom labels specific to the profile payload that is sent.
 
+{{< note theme="warning" >}}
+
+On Upsun, `application_name` is set to application name by default. If you override this value, you might
+not be able to see it on the profiling tab.
+
+{{< /note >}}
+
 The Python continuous profiler API has two functions:
 
 ```python