add environment var to explicitly indicate containerized and allow running as root (#1327)

docker/Dockerfile

@@ -5,4 +5,5 @@ ADD minio.dockerimage /minio
 ADD export /export
 EXPOSE 9000
 COPY start.sh /start.sh
+ENV ALLOW_CONTAINER_ROOT=1
 ENTRYPOINT ["/start.sh"]

runtime-checks.go

@@ -41,6 +41,11 @@ func isContainerized() bool {
 		}
 	}
 
+	// Check if env var explicitly set
+	if allow := os.Getenv("ALLOW_CONTAINER_ROOT"); allow == "1" || strings.ToLower(allow) == "true" {
+		return true
+	}
+
 	/* Add checks for non-docker containers here. */
 	return false
 }