Unable to Manage Engines from Web UI

Symptom

After Adding FME Engines on a Separate Machine, the new engine host does not appear under the Engines > Hosts section of the FME Flow UI, although the engines themselves may be listed. This issue prevents adjusting the number of engines running on this host.

Cause

Several issues could be causing this problem:

1. The FME Flow installation was initially completed using the express option, and FME Engines were later added to a separate machine. However, the necessary database update step was missed, resulting in the Engine host being unable to locate the System Database.

2. The hostname reported by the FME Engine machine is not resolvable by the FME Flow Core.

3. The FME Engine is unable to establish a connection with the System Database.

4. There is a time zone mismatch between the Core and Engine hosts.

5. Essential network ports are blocked or closed.
6. The Engines are failing to connect to the Job Queue

 

Resolution

1. Adjust Database Access Settings
On the Core host, edit the pg_hba.conf file located at %ALLUSERSPROFILE%\Safe Software\FME Flow\pgsql\data. Modify the following lines:

host    all     all     127.0.0.1/32      scram-sha-256
host    all     all     ::1/128          scram-sha-256

to:

host    all      all       0.0.0.0/0         scram-sha-256
host   all      all     ::/0             scram-sha-256

This adjustment allows the Engine host to access the System Database from any IP address, resolving potential communication issues. Restart the FME Flow Database and FME Flow Engines services to apply these changes. See the documentation for more information.

2. Check Database Connection Information

Confirm that the database connection details in fmeDatabaseConfig.txt are accurate, especially the DB_JDBC_URL, DB_USERNAME, and DB_PASSWORD. This ensures the Engine can connect to the System Database. Note that in older FME Flow versions, this information might be located in fmeCommonConfig.txt and/or fmeServerWebApplicationConfig.txt.

3. Synchronize Time Zones

Ensure that both Core and Engine hosts are set to the same time zone. Time zone discrepancies can lead to synchronization issues, affecting host communication.

4. Open Necessary Network Ports

Verify that ports 7069, 7070, 7071, and 7500 are open on the Engine. These ports are required for proper communication between the Core and Engine hosts. For additional details, refer to the FME Flow ports diagram here. Additionally, check that your Windows Firewall settings are configured to allow traffic through these ports.

5. Verify Job Queue Connectivity

Ensure that the Core host can connect to the Job Queue. This connection is crucial for the Engines to receive and process jobs correctly. For more information on ensuring job queue connectivity, consult this known issue for troubleshooting.