added logging

docs/admin/configuration/logging.md

@@ -0,0 +1,49 @@
+---
+sidebar_position: 13
+id: logging
+title: Logging
+---
+
+# Logging in OpenCloud
+
+---
+
+## Introduction
+
+Logging helps monitor OpenCloud’s health and diagnose issues. Log output varies by level, from minimal to detailed. By default, logs are written to `stderr`. In Docker deployments, logs are accessible via `docker logs`.
+
+---
+
+## Log Levels
+
+Set the global log level using the `OPEN_CLOUD_LOG_LEVEL` environment variable. You can also override it per service using service-specific variables. Default is `error`.
+
+## The log levels are:
+
+### FATAL
+Critical issues that cause the application to shut down — such as config errors or missing dependencies.
+
+### ERROR
+Severe problems that block proper operation and require admin attention.
+
+### WARN
+Unexpected conditions that don’t stop the app but may need investigation.
+
+### INFO
+Routine events that confirm expected behavior and operation.
+
+### DEBUG
+Highly detailed messages for diagnosing problems. Use cautiously in production due to verbosity.
+
+---
+
+## Request Correlation
+
+### X-Request-ID
+
+OpenCloud supports tracing using the `X-Request-ID` header. Clients send a UUID v4 with each request, which is included in backend logs for correlation.
+
+To manually test with `curl`, add:
+
+```bash
+--header "X-Request-ID: <your-id>"