Troubleshooting gcluster_rsynctool IP Mapping Errors in GBase 8a

The gcluster_rsynctool utility synchronises tables between two GBase 8a clusters. When the clusters use private internal IPs, an IP mapping file is used to translate them into routable external IPs during synchronisation. This article covers two common connection errors related to IP mapping and how to resolve them quickly in a gbase database environment.

Error 1: Can't connect to GBase on 'X.X.X.X:5050' (timed out)

Symptom

The sync tool fails to connect to a cluster node's internal IP address and times out.

Root Cause

The IP mapping has not taken effect. The tool is still trying to reach the node using its private, unreachable IP instead of the translated external IP.

How to Fix

1. Verify that the mapping file parameters are correctly specified when launching the tool:
   • --master_mpp_ip_mapping_file for the source cluster
   • --slave_mpp_ip_mapping_file for the target cluster
2. Open the mapping file and confirm that the IP addresses are entered correctly and that the FROM (private IP) and TO (external IP) columns are not swapped.

Error 2: Initialize master gcluster topology failed: Y.Y.Y.Y is not in mapping

Symptom

The tool fails during topology initialisation, reporting that a specific IP Y.Y.Y.Y is not found in the mapping file.

Root Cause

A cluster node's private IP is missing from the FROM column of the mapping file, so the tool cannot translate it.

How to Fix

1. Check for typos in the IP addresses — the reported IP must match exactly with the entry in the mapping file.
2. Check the mapping direction — the format is FROM (private IP) TO (external IP). If the external IP is mistakenly placed in the FROM column, all mappings will be incorrect.

A correct mapping entry looks like this:

192.168.1.10 10.0.0.10

Here 192.168.1.10 is the internal IP reachable within the cluster, and 10.0.0.10 is the external IP visible to the other cluster.

Summary

Proper IP mapping configuration is the key to successful cross‑network synchronisation with gcluster_rsynctool. When you encounter connection timeouts or topology initialisation failures, always inspect the mapping file parameters and the file content first — this resolves the majority of such issues in a gbase database setup.