Do not set TraceProvider to global (#5138)

The reason is because soon we will have the config for the tracing/metrics providers in the main config (already started).
When this happens then we can have users "reconfigure" that via the watch API, and re-setting the global is not allowed in otel (also not restart friendly). Because of that we should break this behavior now, and not install the global.

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### 🛑 Breaking changes 🛑
 
 - Remove deprecated structs/funcs from previous versions (#5131)
+- Do not set TraceProvider to global otel (#5138)
 
 ### 🚩 Deprecations 🚩
 

service/collector.go

@@ -27,7 +27,6 @@ import (
 	"syscall"
 
 	"go.opentelemetry.io/contrib/zpages"
-	"go.opentelemetry.io/otel"
 	"go.opentelemetry.io/otel/metric"
 	"go.opentelemetry.io/otel/metric/nonrecording"
 	sdktrace "go.opentelemetry.io/otel/sdk/trace"
@@ -231,10 +230,6 @@ func (col *Collector) Run(ctx context.Context) error {
 		sdktrace.WithSampler(internal.AlwaysRecord()),
 		sdktrace.WithSpanProcessor(col.zPagesSpanProcessor))
 
-	// Set the constructed tracer provider as Global, in case any component uses the
-	// global TracerProvider.
-	otel.SetTracerProvider(col.tracerProvider)
-
 	col.meterProvider = nonrecording.NewNoopMeterProvider()
 
 	col.asyncErrorChannel = make(chan error)