fix: use 127.0.0.1 for volume server IP registration

- Change volume -ip from seaweedfs-volume to 127.0.0.1
- Change -publicUrl from localhost:8080 to 127.0.0.1:8080
- Volume server now registers with master using 127.0.0.1
- Filer will return 127.0.0.1:8080 URL that's resolvable from host
- Fixes UnknownHostException for seaweedfs-volume hostname

test/java/spark/docker-compose.yml

@@ -27,7 +27,7 @@ services:
     ports:
       - "8080:8080"
       - "18080:18080"
-    command: "volume -mserver=seaweedfs-master:9333 -ip=seaweedfs-volume -ip.bind=0.0.0.0 -port=8080 -port.grpc=18080 -publicUrl=localhost:8080 -preStopSeconds=1"
+    command: "volume -mserver=seaweedfs-master:9333 -ip=127.0.0.1 -ip.bind=0.0.0.0 -port=8080 -port.grpc=18080 -publicUrl=127.0.0.1:8080 -preStopSeconds=1"
     depends_on:
       seaweedfs-master:
         condition: service_healthy