OpenTelemetry's Zipkin remote endpoint cache could grow without bounds and increase memory pressure

Summary

The Zipkin exporter remote endpoint cache accepted unbounded key growth derived from span attributes. In high-cardinality scenarios, this could increase process memory usage over time and degrade availability.

Details

• Introduce a bounded, thread-safe LRU cache for remote endpoints.
• Enforce fixed maximum size to prevent unbounded growth.

Impact

• A process using Zipkin export for client/producer spans could experience avoidable memory growth under sustained unique remote endpoint values.

Resources

#7081